EPA910/R-94-004
oEPA
            United States
            Environmental Protection
            Agency	
              Region 10
              1200 Sixth Avenue
              Seattle WA 98101
Alaska
Idaho
Oregon
Washington
            Water Division
              Wetlands Section
                                        April 1994
Seagrass Science and Policy
in the Pacific Northwest:
             Proceedings of a Seminar Series


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Front Cover Photo
Gathering Abalone (C. 1914) by Edward S. Curtis.
A black and white photograph of Jessie Sye, a Hesquiat woman, harvesting abalone. She belongs to
the Nootka (Nuu-Cha-Nulth) group (Figure 1, Chapter II). On Close examination, Phyllospadix spp.,
surfgrass, rises from the tide pool in the foreground. Plants are also growing just above the water line
on the surrounding rocks. The photograph is part of a special collection detailing the activities of
Pacific Northwest Natives (NAI folio V. 10, p1 342) and housed at the Special Collections and
Preservation Division of Allen Library, University of Washington, Seattle, Washington 98195
Curtis, E.S. 1915. The North American Indian. Vol. 10 Johnson Reprint Collections.
Back Cover Photo
Basketry Whalers’ Hat; late 18th to early 19th century
(Spruce root, cedar bark and surfgrass)
This Basketry Whaler’s Hat was believed to have been collected by Lewis and Clark during their
winter stay at the mouth of the Columbia River. Although it was bought from a resident of the
Columbia River region, it was, most likely, made by the whaling people of the coast of Washington or
Vancouver Island, Canada. The warp is split spruce root, the weft is black-dyed cedar bark with an
overlay of sun-bleached surfgrass. (Information taken from “A Time of Gathering” edited by Robin K.
Wright, University of Washington Press, 280 pp.).
Photograph obtained from Peabody Museum, Harvard University, photographed by HeIleI Burger.
Photo No. N31728. Cat No.99-12-10/53080.

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Seagrass Science and Policy in the Pacific  Northwest:
                  Proceedings of a Seminar Series
                                  EDITORS:

                             Sandy Wyllie-Echeverria
                                Annette M. Olson
                                     and
                                Marc J. Hershman

                       Interdisciplinary Seagrass Working Group
                              School of Marine Affairs
                             University of Washington
                             Seattle, Washington 98195
                                PREPARED FOR:

                         U.S. Environmental Protection Agency
                                   Region 10
                                Seattle, Washington
                           Fred Weinmann, Project Officer
                              This report should be cited:
       Wyllie-Echeverria, S, A.M. Olson and M.J. Hershman (eds). 1994. Seagrass science and policy in the
                 Pacific Northwest: Proceedings of a seminar series. (SMA 94-1).
                               EPA910/R-94-004. 63pp.

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II- Seagrass Science and Poilcy
Table of Contents
List of Figures iii
List of Tables iii
Preface iv
Acknowledgments v
Introduction 1
1. Seagrasses of the Northeast Pacific 4
by Sandy Wyllie-Echeverria and R. C. Phillips
Scientific Issues 11
2. Faunal Associations and Ecological Interactions in
Seagrass Communities of the Pacific Northwest Coast
byCharlesA. Simenstad 11
3. Incorporating the Population Biology of Eelgrass
into Management
by Mary H. Ruckelshaus 19
4. Light Environments/Implications for Management
by Douglas A. Bulthuis 23
Management Issues 29
5. Inventory of Seagrasses: Critical Needs for
Biologists and Managers
by Thomas F Mum ford, J 29
6. Seagrass Management in Washington State
by Kurt L. Fresh 38
7. Restoration of Damaged Eelgrass Habitats
by Ronald M. Thom 42
Frameworks for Analysis of the Issues 47
8. Evaluating and Developing Seagrass Policy in the
Pacific Northwest
by Marc J. l-Iershman and Kent A. Lind 48
9. Ecological Models in Research on Eelgrass:
An Approach to Setting Research Priorities
byAnnette M. Olson andAlton Straub 54
Concluding Remarks 61

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iii - Seagrass Science and Policy
List of Figures
Page Figure
5 Distribution of Northeast Pacific seagrasses
7 Tirrieline depicting seagrass science along the west Coast of North America
14 Composite food web characteristics
19 Ecological and genetic differentiation in eelgrass populations of the Northeast Pacific
24 Dynamics of light attenuation in nearshore seagrass communities
39 Unofficial Washington Department of Fisheries seagrass management model
44 Frameworks for analysis of management and scientific issues
47 Evaluating current seagrass policies in the Pacific Northwest
49 Designing, implementing and evaluating new seagrass policies
List of Tables
Page Table
4 Adaptations of vascular plants for life in the sea
6 Classification of Northeast Pacific seagrasses
6 Major functions of seagrasses
37 Projects in Washington State where seagrass is an issue
42 Questions to pose in restoring an eelgrass meadow
41 Aspects of landscape ecology that can be used in siting and designing eelgrass
restoration projects
52 What is an ecological model?
54 Alternative models for eelgrass decline

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iv - Seagrass Science and Policy
Preface
This report from the seminar, Seagrass Science and Policy, represents a convergence of
science and policy. It is a timely step in a continuum of events necessary for knowledgable long-term
management which ensures maintenance of seagrass functions in the Pacific Northwest. Taking the
next steps will be critical in determining the extent to which such functions will be sustained.
Pioneering eelgrass research was completed by Dr. Ronald Phillips in the 1960s and ‘70s.
This work provided an excellent basis for expansion of investigations into broader ecosystem func-
tional studies. Such studies, while developed and proposed by individuals and consortiums of scien-
tists, have never been completed. As a result, follow-on research has been sporadic and often
specific to single projects. In fact, we are still struggling to complete a scientifically sound eelgrass
inventory for Washington State.
In the meantime, permit applications for marinas, dredging, and other port development
activities continue. Regulatory agencies are required to continue making decisions regarding the long
term fate of seagrasses with limited information. These permit applications inevitably spawn ques-
tions: To what extent can seagrass beds be restored? How will seagrass beds be affected? How can
we get beyond piecemeal, project-by-project management?
This seminar represents the kind of initiative which can help to focus attention on the impor-
tant issue of seagrass management in the Pacific Northwest. Seminar results reveal needed actions
and at the same time tender technical and managerial challenges. Meeting these challenges will
benefit citizens, resource agencies, land managers, and regulators.
Fred Weinmann
U.S. Environmental Protection Agency
Region 10

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v - Seagrass Science and Policy
Acknowledgments
This document was prepared by the Interdisciplinary Seagrass Working Group (ISWG),
School of Marine Affairs, University of Washington. Members of the ISWG include Marc J. Hershman,
Annette M. Olson, and Sandy Wyllie-Echeverria. Financial support was received from the U.S.
Environmental Protection Agency, Region 10. Fred Weinmann provided suggestions that helped us
frame our ideas. We gratefully acknowledge review comments by Andrea Copping. The ethnobotani-
cal information, presented in Sea grasses of the Northeast Pacific, this volume, was gathered under a
grant from the Hardman Foundation, and Mr. Malcolm Rea. We also acknowledge Peggy Stafford and
Marcus Duke for their editorial and production assistance, as well as the staff of the School of Marine
Affairs whose editorial assistance is much appreciated. Sandra Kroupa, Book Arts Librarian, was very
helpful in obtaining the cover photograph. The students of SMA 550Z, Seagrass Science and Policy
Seminar, supplied helpful comments during the course of the seminar. Lastly, the editors especially
thank the other contributors to this volume, Charles Simenstad, Mary Ruckelshaus, Doug Bulthuis,
Tom Mumford, Kurt Fresh and Ron Thom for their work and effort to provide not only informative and
provocative lectures during the seminar, but also to craft their remarks into cohesive summaries for
this volume.

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INTRODUCTION
Seagrasses are a vital, living marine resource whose presence is critical in nearshore food
web dynamics. As such, they have been a focus of scientific inquiry and natural resource manage-
ment in many coastal states for several decades. In the Pacific Northwest (PNW), natural scientists
have investigated seagrass ecosystems since the mid 1960’s. Their results, coupled with research
from other regions, led to the formulation of seagrass management policies. These policies are
formulated to address human activity that might impact seagrasses. If impacts on seagrasses are
expected, projects or activities (e.g. dock construction or expansion, dredging and filling) may be
modified or abandoned, or some kind of habitat replacement required.
There has also been an effort to quantify the amount of seagrass habitat. Although much of
this work has centered on Zostera marina L., eelgrass, and to a lesser degree on Zostera japonica,
some information exists on the other species. However, it is important to note that a comprehensive
baseline map for all seagrass species in the Pacific Northwest is lacking.
Although an informal seagrass management program (including plans to provide accurate
distribution maps) exists at both the state and federal level, to date there has not been a comprehen-
sive policy analysis to determine the effectiveness of this program. Natural resource managers are
left wondering whether current policy is working effectively to protect, conserve and map seagrasses
in the Pacific Northwest.
Recognizing that the School of Marine Affairs (SMA), University of Washington could provide a
forum to address this question, the Interdisciplinary Seagrass Working Group (ISWG) was formed in
the fall of 1992. Our goal was to examine current seagrass management programs in the PNW, using
an interdisciplinary approach. As a first step in this process, we offered a Special Seminar Series,
“Seagrass Science and Policy” (SMA 550Z), during Spring Quarter, 1993. The seminar met weekly for
discussions with some of the key figures in seagrass science and policy in the PNW.
The academic program at SMA is designed, in part, to prepare students to face the challenges
of careers in coastal zone management. A goal of the Special Seminar Series was to acquaint
students with current science and policy issues relative to coastal zone management. Accordingly, the
seminar was structured to explore seagrass management questions as a microcosm of more broadly
based management concerns. Thus, the objectives of the weekly sessions were to: 1) describe, in
some detail, the biology and ecology of seagrass resources in the PNW; 2) delineate the types of
human activity that were threatening to these resources; 3) define current management strategies to
offset these threats; and 4) suggest ways in which seagrass management might be more efficient and
effective. Consequently, invitations were extended to speakers who had helped shape the current

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2 - Sea grass Science and Policy
seagrass management policies and programs in the PNW. We asked speakers to concentrate on two
questions:
• Are seagrass resources unique or different in this region?
• Is management history or authority that affect seagrasses unique or different in the PNW?
A second goal was to involve a broader audience in ongoing seagrass science and policy
discussions with the ISWG. This volume, summarizing the seminar speakers’ remarks will be used to
reach a wider audience. The first chapter, Seagrasses of the Northeast Pacific, by Sandy Wyllie
Echeverria and Ronald C. Phillips, places PNW seagrass science and policy in a broader historical
and geographical framework. The remaining chapters are ordered under the headings of Scientific
Issues, Management Issues, and Frameworks for Analysis of the Issues.
Under Scientific Issues are contributions by Charles A. Simenstad, Mary H. Ruckelshaus and
Douglas A. Buithuis (chs. 2-4). Simenstad describes faunal assemblages associated with seagrass
communities. He highlights the role of seagrasses in providing “vertical structure” in the water column
for shelter, substrate and food. A more comprehensive understanding of basic seagrass biology is
offered as the major hurdle confronting effective management. Ruckeishaus reports the current
understanding of genetic variation in seagrasses and its relevance to restoration. The challenge for
management, she argues, is to resolve which biological/ecological criteria are important to ensure
seagrass persistence. Buithuis sets the issue of light management, regarding Pacific Northwest
seagrasses, in a global context. He presents a summary of the factors inhibiting available light and
advocates the development of “... meaningful criteria for water clarity
The section on Management Issues presents the contributions of Thomas F. Mumford, Kurt L.
Fresh and Ronald M. Thom (chs. 5-7). Mumford provides a summary of seagrass inventory tech-
niques and their possible application in the Pacific Northwest. He urges resource managers to adopt a
“business analysis plan” to chart a direction commensurate with goals and funds. Fresh places
Washington Department of Fisheries in the context of regional seagrass management programs. He
provides a summary of seagrass mitigation projects in Washington state and details a conceptual
model used to process a seagrass mitigation project. He advocates augmenting communication with
“user/client groups” to “increase the public’s confidence in seagrass management.” Thom urges the
use of concepts from the field of landscape ecology in thinking about and planning for seagrass
management. He also challenges managers to design transplants capable of withstanding background
natural disturbances (e.g. winter storms). Developing and testing transplant technologies are included
in his list of challenges to proper seagrass management.
Frameworks for Analysis of the Issues (chs. 8 and 9) includes two papers. Marc J. Hershman
and Kent Lind present a framework for analyzing the legal and institutional context for seagrass
science and policy development. They provide an overview of seagrass protection and management
policies in the PNW and suggest a procedure for designing, implementing and evaluating new

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3 - Seagrass Science and Policy
seagrass policies. Annette M. Olson and Alton Straub focus on the development of a research agenda
for eelgrass science in the PNW, with the goal of identifying research programs that both answer
important ecological questions and address the information needs of environmental decision-makers.
They present a method for evaluating the scientific knowledge base and suggest ways to link their
analyses with those of Hershman and Lind.
The Seagrass Science and Policy Seminar identified several key issues for seagrass manag-
ers in the Pacific Northwest, including
• the potential for non-point source impacts on the quantity and quality of habitat suitable for
persistence of seagrasses;
• the need for resource inventories documenting seagrass distributions and characterizing
populations;
• the need for restoration of seagrass systems destroyed by coastal zone development;
• enhanced coordination of regulatory and management activities;
• ethnobotanical information and its relevance to policy decisions;
• comparative studies with seagrass systems and policy agendas and activities in other
regions of the U.S.; and
• the need for linking management research with basic ecological research.
We have designed this publication to inform regional seagrass management. Each chapter
addresses areas of concern and suggests new directions necessary to implement policies and pro-
grams that protect and conserve seagrasses. We hope to stimulate and contribute to a regional
dialogue on these issues. Additionally, we confirm that the issues identified in the Special Seminar
Series will be the focus of further study and recommendations by the Interdisciplinary Seagrass
Working Group.

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4 - Seagrass Science and Policy
1. Seagrasses of the Northeast Pacific
Sandy Wyllie-Echeverria
School of Marine Affairs, HF-05
University of Washington
Seattle, Washington 98195
and
R. C. Phillips
Battelle - Pacific Northwest Laboratory
P0. Box 999; MS/N: P7-68
Rich/and, Washington 99352
Seagrasses are a unique suite of plants that inhabit the margins between land and sea
(Phillips and Menez 1988). There are 12 genera with approximately 50 species (den Hartog 1970;
Phillips and Menez 1988). As distinct from marine algae, seagrasses are rooted in the sediment or
rocky crevices and produce seeds (Arber 1920) (Table 1). They occur in tropical, temperate and
subarctic coastal waters throughout the world (den Hartog 1970; Phillips and Menez 1988).
In the Northeast Pacific, the seagrass flora includes six species in two genera in the family
Potamogetonaceae (Table 2). The distribution of all species is graphically displayed in Figure 1. The
most cosmopolitan species, Zostera marina (eelgrass), and its role in coastal food webs, is the
primary focus of both science and policy in this region (Phillips 1984). The recently introduced plant
(1930’s and early 1940’s), Z. japonica (Harrison and Bigley 1982) is beginning to warrant attention
from both seagrass scientists and natural resource managers (see Simenstad and Fresh, this vol-
ume). However, the three species of Phyllospadix (surtgrass), have received little attention, and Z.
asiatica was only recently described (Phillips and Wyllie- Echeverria 1990). Five of the six species
found in the Northeast Pacific occur along the rocky shores and soft-bottom habitats of the Pacific
Northwest (Fig.1).
Historically, Pacific Northwest coastal natives 1 had
Table!
many uses for eelgrass (Boas 1921, Kuhnlein and Turner 1991; Adaptations of vascular plants for
Turner in prep). Most notable were uses by the life in the sea
Kwakwaka’wakw (formerly Kwakiutl) and 1-laida people 1. Adapted to life in a saline medium.
(Kuhnlein and Turner 1991). The Kwakwaka’wakw had an 2. Able to grow completely submerged.
elaborate technique for gathering and eating eelgrass. They 3. An anchoring system able to withstand
fashioned “eelgrass twisting sticks”, and, from a boat, harvested wave action and tidal currents.
the plants by twisting the leaves around the “sticks” and pulling 4. The capacity for hydrophilous (by the
agency of water) pollination.
the plants from the mud (Boas 1921; Kuhnlein and Turner
Arber (1920)
1991). The uncooked, washed rhizomes, from a bundle of four
plants, were eaten after being dipped in fish oil. It was believed that this dish was the “food of their
first mythical people” (Boas 1921; Kuhnlein and Turner 1991). The Haida concocted a tonic for uterine
1 The location of the Pacific Northwest native groups mentioned in this section can be found in Fig.1.

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5 - Sea grass Science and Policy
Figure 1. DistributIon of Northeast Pacific seagrasses (after Phillips and Menez 1988). The symbols depict the overall range for each
species. Although the symbols may coincide with actual seagrass locations, this is an artifact of placing them on the coastline. Notice
that 5 of the 6 species inhabit the tidal flats and rocky shores of the Pacific Northwest. The coastal native peoples, mentioned in the text
are also referenced (after Northwest Coast volume of the Handbook of North American Indians, Suttles, ed.)
Alas
/4’
*
ANADA
waki uti
Zostera as!at!ca
Zostera marina
Zostera japonica
- adix scouleri
Phyllospadix serrulatus
I
Phyllospadix torrey!

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6 - Sea grass Science and Policy
or stomach problems with “four eelgrass roots (probably rhizomes), each from a different tidepool on
the side towards the sunrise” (Turner in prep).
The Makati used surtgrass (P torreyi) for decorative relief in basketry (Gill 1982). They were
also known to eat the rhizomes of several plants
Classification of Northeast Pacific seagrasses (P torreyi, P scouleri, and, quite possibly,
Zmarina) (Swan 1870, Gunther 1945; Gill 1982).
DIVISION: Arithophyta
CLASS: Monocotyledoneae Most interestingly, the Coastal Chumash (Santa
ORDER: Helobiae Barbara, California region) fashioned seagrass
FAMILY: Potamogen\tonaceae
GENUS: Zostera skirts (P torrey!) (Timbrook and Hoover n.d.).
SUBGENUS: Zoslera
Zostera asiatica Samples of seagrass thatch from this region
Zost era marina have been dated to 1860 ±340 bp (Timbrook and
SUBGENUS: Zosterella
Zosterajaponica Hoover n.d.; Orr 1968).
GENUS: Phyllospadix
Phyllospadixscouleri In the early part of this century, W.A. Setchell
Phyllospadix serrulatus pioneered an eelgrass research project from the
Phyllospadix torreyi
Department of Botany, University of California,
Phillips and Menez (1988) Berkeley. Setchell assembled a network of
_________________________________________ scientists, on both coasts, from whom he re-
ceived both plant data and water and air tem-
peratures (Setchell 1922; 1927; 1929). These collections took place over several years and with
these data he was able to provide a comprehensive and detailed description of the morphological and
phenological status of Zostera marina (Setchell 1929).
Later, and as a response to the effects of the “wasting disease” (loss of eelgrass) and impacts
to several species of waterfowl, most especially the sea goose or black brant (Branta bernicla), careful
and explicit observations by several U.S. Fish and Wildlife biologists were undertaken ( Moffitt and
Cottam 1941, Einarsen 1965). Most notable was the work of
Clarence Cottam and James Moffitt. Cottam and Moffitt, in the
mold of Setchell, assembled reports from natural scientists, game
wardens, oystermen, interested citizens and U.S. Fish and
Wildlife personnel to describe eelgrass abundance at several
sites along the Pacific Coast (Moffitt and Cottam 1941). This
qualitative “eelgrass census” was updated in 1954 (Cottam and
Munro 1954). These observations represent the only biological/
ecological inquiries, relative to Northeast Pacific eelgrass, be-
tween the investigations of Setchell, which ended in 1929, and the
more “modern” inquiries beginning in the early 1960’s (Fig. 2).
U.S. Fish and Wildlife continues to monitor eelgrass at several
West Coast sites (e.g. Ward and Stehn 1989). The “modern”
Table 3
Major functions of seagrasses
1. Stabilize bottom sediments
2. Slow and retard current, promot
ing sedimentation and inhibiting
resuspension of organic and inor
ganic matter
3. Shelter and substrate
4. Direct (grazing) and indirect
(detritus) feeding pathways
5. High production and growth
6. Internalized nutrient cycles
Wood, Odum and Zieman (1969)

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WEST COAST
SEAGRASS SCIENCE
Setchell
1900 1925
rnuups
McRoy
Harrison
Bayer, Felger, Simenstad
Thom, Williams
Ibarra-Obando
Kitting
Alberte, Bulthuis
Koffman
Ruckeishaus
Dennison (‘79) Wylhe-Echeverna
Zimmerman
+
Backman (‘83)
Kentula (‘83)
Short (‘81)
Dethier (‘81)
________ _____________
Scagel, Brayshaw, Dethier
Dawson
-
Merkel
Wyllie-Echeverria (1993)
Figure 2. Timeline depicting seagrass science along the West Coast of North America. The bars above the arrow, in most cases, refer to research conducted at various west coast universfties.
Below the arrow, in descending order, the bars refer to: 1) USFW research scientists; 2) marine ecologists noting seagrasses in their published works and 3) E.Yale Dawson, a noted phycologist who had
an untimely death as a resuft of a diving accident and Ke h Merkel, an environmental consultant who has developed west coast seagrass transplanting techniques. The names referenced by dates refer to
graduate degrees that contributed to an understanding of west coast seagrasses. These scientists, in some cases, pursued seagrass investigations in other regions.
Young
Porter (‘67)
Keller (‘63)
Turner
Waddell (‘64)
Moody (‘78)

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8 - Sea grass Science and Policy
inquiries have been directed by a number of individuals at different sites but investigations remain
continuous since the 1960’s (Fig. 2).
Eelgrass has been at the center of both science and management concerns in the Northeast
Pacific. This is based on the premise, supported by scientific inquiry, that eelgrass prairies provide
valuable shelter, food and substrate in coastal environments. Important species, most often associated
with eelgrass, include juvenile salmon (Oncorhynchus spp.), Pacific herring (Clupea harengus pa/las!
sp.) and black brant (Phillips 1984; Einarsen 1965).
When the word seagrass is used, the reader should know that, in most cases, the reference
is to eelgrass. This is both positive and negative. On the positive side, there is some recognition on the
part of both scientists and resource managers that, even though particular seagrasses occupy differ-
ent habitats (e.g. eelgrass, Z japonica and Z. asiatica - soft bottom dwelling, primarily, and
Phyllospadix spp. - rocky shores, primarily), all might provide similar functions. These functions were
first identified by Wood, Odum and Zieman (1969) (Table 3) and are taken to be critical contributors in
the dynamics of coastal food webs (Phillips 1984). On the other hand, the liberal use of the word
seagrass might imply that there is not only a detailed scientific understanding of all species in the
Northeast Pacific, but also a management strategy based on this knowledge. Both assumptions would
be false.
As mentioned, networks formed to facilitate information exchange have been crucial in the
history of seagrass science in the Northeast Pacific. A recent regional synthesis of seagrass research
gaps and needs revealed that this “cooperative spirit” still exists (Wyllie-Echeverria and Thom in
press). This “cooperative spirit” linked to the research priorities and management frameworks,
described in this document, provide the basis for regional management of the seagrass component of
submerged lands.
Literature Cited
Arber, A. 1920. Water plants, a study of aquatic angiosperms. Cambridge University Press. 436 pp.
Boas, F. 1921. Ethnology of the Kwakiutl. Bur. Amer. Ethnology, 35th Ann. Rep. Part 1, 1913-14. Smithsonian
Institution, Wash. D.C.
Cottam, C. 1939. The eelgrass situation on the American Pacific Coast. Rhodora 41:257-260.
Cottam, C., and D.A. Munro 1954. Eelgrass status and environmental relations. J. Wild!. Man. 18(4):449-460.
den Hartog, C. 1970. The seagrasses of the world. Amsterdam: North-Holland Publication Co. Amsterdam. 275
pp.
Einarsen, A.S. 1965. Black Brant, sea goose of the Pacific. University of Washington Press, Seattle. 142 pp.
Felger, R.S., and M.B. Moser. 1985. The people of the desert and sea: Ethnobotany of the Sen Indians.
University of Arizona Press, Tucson. 438 pp.
Gill, S.J. 1982. Ethnology of the Makah and Ozette people, Olympic Peninsula, Washington, USA. PhD. Diss.
Washington State University, Pullman. 445pp.

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9 - Sea grass Science and Policy
Gunther, E. 1945. Ethnobotany of Western Washington: The knowledge and use of indigenous plants by Native
Americans. University of Washington Press. 7lpp.
Harrison, P. G., and R.E. Bigley 1982. The recent introduction of the seagrass Zostera japonicaAschers. and
Graebn. to the Pacific coast of North America. Can J. Fish. Aquat. Sci. 39:1648-1648.
Kuhnlein, H.V., and N.J. Turner. 1991. Traditional plant foods of Canadian indigenous peoples: nutrition,
botany and use. Gordon and Breach Science Publishers. Philadelphia, Reading, Paris, Montreux, Tokyo,
and Melbourne. 633pp.
Moffitt, J., and C. Cottam. 1941. Eelgrass depletion on the Pacific coast and its effect upon the black brant.
U.S.Fish WildI. Serv. WildI. Leafl. 204. 26pp.
Orr, P.C. 1968. Prehistory of Santa Rosa Island. Santa Barbara Museum of Natural History. Santa Barbara, CA.
253pp.
Phillips, R.C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: A community profile. U.S. Fish
Wildl. Serv. FWS/OBS-84/24. B5pp.
Phillips, R.C., and E.G. Menez. 1988. Seagrasses. Smithsonian Contributions to the Marine Sciences, no. 34.
lO4pp.
Phillips, R.C., and S. Wyllie-Echeverria. 1990. Zostera asiatica Miki. on the Pacific Coast of North America.
Pacific Science. 44(2): 130-134.
Setchell, W.A. 1922. Zostera marina in its relation to temperature. Science 54: 575-577.
Setchell, W.A. 1927. Zostera marina latifolia: ecad or ecotype? Journal of the Torrey Botanical Club 54:1-6.
Setchell, W.A. 1929. Morphological and phenological notes on Zostera marina L. Univ. Calif. PubI. Bot.
14:389-452.
Swan, J.G. 1870 The Indians of Cape Flattery. Smithsonian Contributions to Knowledge. No. 220.
Timbrook, J., and R. Hoover. n.d. Chumash ethnobotany. Unpublished manuscript. Santa Barbara Museum of
Natural History, Santa Barbara, California.
Turner, N.J. (in prep). Haida ethnobotany.
Ward, D.H., and R.A. Stehn. 1989. Response of brant and other geese to aircraft disturbances at Izembek
Lagoon, Alaska. U.S. Fish and Wildl. Serv. Rep., Anchorage, AK 248pp.
Wood, B. L. F., W. E. Odum and J. C. Zieman. 1969. Influence of seagrass on the productivity of coastal
lagoons. Pp. 495-502 in Mem. Symp. Internat. Costeras (UNAM-UNESCO), 28-30 Nov., 1967.
Wyllie-Echeverria, S., and R.M. Thom. Managing west coast seagrasses: research gaps and needs (in press
with Alaska Sea Grant; available Spring 1994).

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11 - Sea grass Science and Policy
SCIENTIFIC ISSUES
2. Faunal Associations and Ecological Interactions
in Seagrass Communities of the Pacific Northwest Coast’
Charles A. Simenstad, Coordinator
Wetland Ecosystem Team
Fisheries Research Institute
School of Fisheries, WH- 10
University of Washington
Seattle, Washington 98195
Seagrass communities likely rank with marine kelp (macroalgae) systems as the marine
analog to tropical rain forests in structural complexity, biodiversity, and productivity. In many aspects,
they easily exceed the touted terrestrial ecosystems. By their position at the land-ocean margin,
seagrass communities are also an integral element in the continuum of material and organismal
transport along the estuarine environmental gradient. That gradient is a conduit for sediments, organic
matter, nutrients and biota that cross the land margin, often in both directions. At the polyhaline
transition in estuaries, seagrass habitats are situated at the “node” of material transformation and
biotic transition. Undoubtedly, the best known biota passing through estuarine seagrass habitats are
juvenile anadrornous fishes such as Pacific salmon (Oncorhynchus spp.), but many other important
ecological, physical, and geochemical processes are concentrated within seagrass habitats.
This paper is a synopsis of one aspect of these seagrass community processes, e.g., that of
ecological linkages involving biota directly or indirectly dependent upon seagrasses. I will primarily
address two aspects of seagrass communities: (1) assemblages of organisms that are discretely
associated with seagrass habitats, and their interaction within the habitat; and (2) linkages between
the community and the (estuarine) ecosystem within which it is set. This perspective will emphasize
trophic-dynamics aspects (serisu Lindeman 1942) of the seagrass communities, not only because
that has been the research focus of myself and my colleagues, but also because I believe that many
of the more important ecological functions (e.g., “services” 2 ) provided our society and economy are
1 With apologies to the seminar series organizers, I choose to call the seagrass habitat and its associated flora and fauna
“communities” based on definitions such as Menge and Sutherland’s (1976) “an association of interacting population of all
trophic levels occurring in a given habitat;” my view of “ecosystem” Is more holistic, encompassing both the blotic components
(communities) and ablotic environment with which they interact. Thus, at a minimum, seagrass communities exist within
coastal or estuarine ecosystems and may actually be incorporated into the whole land-ocean ecosystem, from watershed to
open ocean.
2 I distinguish “ecological functions” from “ecological processes” in this case. Of the multitude of ecological processes that
are occurring In any ecosystem, ecological functions are restricted to those to which we as a society and culture have
attached particular Importance; “ecological values” would be a subset of the functions, i.e., those that have a particular
economic value attached. Ecological processes are universal and relatively consistent, but ecological functions and values
waft variably as a function of social and cultural (and political!) trends. Thus, parasitism will always be with us as an ecologi-
cal process, but seldom recognized as an ecological function, as would mountain lions feeding on deer or elk, which in turn is
considered a worthwhile function by many segments of our society irrespective of Its marginal economic value.

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12 - Sea grass Science and Policy
accounted for by trophic linkages. Although my focus will be on consumer assemblages and their
ecology in Zostera marina, eelgrass, communities along the northeastern Pacific Northwest coast, I
will try to incorporate some evidence from Z marina communities in other regions and will also
mention the introduced species, Zostera japonica, that has become established in certain estuaries in
this region.
State of Our Understanding
Wood et al. (1969) and Zieman (1982) describe six major functions of seagrasses (Table 3,
ch. 1). Of these, shelter and substrate, direct and indirect feeding pathways, and current mediation are
the most directly responsible for the composition, diversity, production, and trophic interactions of
seagrass consumer organisms. Kikuchi and Pérès (1977) and Kikuchi (1980) also cite maintenance
of high dissolved oxygen and the mitigating effect of shading on water temperatures and salinities as
additional factors under the function of shelter and substrate.
Consumer organisms are both resident and transient members of seagrass communities.
Although some organisms appear in seagrass habitats in no greater incidence than any other habitat,
most occupy the habitat “preferentially’ 3 over other, predominantly unvegetated habitats. The ecologi-
cal, and inherently evolutionary, processes that account for both resident and transient consumer use
of seagrasses relate to increased fitness, e.g., promoting some increased chance for survival to
reproduction. In seagrasses, processes that direct/yincrease fitness could include, but are not
necessarily restricted to (1) unique or enhanced reproduction; (2) optimum foraging that results in
significantly higher growth rates; (3) refuge from predation resulting in increased survival; and (4)
optimization of physiological conditions affecting both growth and survival.
Consumer reproduction in seagrasses is usually associated with plant substrates, either the
seagrass itself or macroalgae that are associated with the community. The best, and most valuable,
example in this region is the importance of many eelgrass sites as Pacific herring (Clupea harengus
pallasi) spawning sites (Phillips 1984: Simenstad 1987). Not all seagrass habitats are herring spawn-
ing sites. We still have no definitive information that explains why certain sites are important and
others are not; we must assume at this stage that either unknown characteristics of these habitats are
unique or that the setting of these sites in the larger scale of estuarine and coastal circulation or other
factors has dictated their importance over evolutionary time.
Optimal foraging implies prey resources that are uniquely or abundantly associated with
seagrass habitats or increased prey capture rates, such that consumers can gain maximal assimila-
tion of prey biomass when feeding within the habitat. Although direct herbivory in other, especially
tropical, seagrass communities is more common, there are relatively few herbivores on Zostera
3 I use this term somewhat loosely, suggesting that there is a volitional behavior toward occupying the habitat preferentially
over other, adjacent habitats but acknowledging that there have been no specific studies, to my knowledge, that have actually
documented “preference” per Se; rather, most studies have just shown higher abundances (or rarely, exclusive occurrences)
in seagrasses than in adjacent habitats

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13 - Sea grass Science and Policy
marina and Z japonica in the Pacific Northwest. Notable exceptions include several species of
waterfowl such as brant (Branfa bern/cia), Canada geese (B. canadens/s), wigeon (Anas americana),
gadwall (A. strepera), and pintail (A. acuta) ducks (Phillips 1984). Isopods (/doteaspp.) may also
constitute another important herbivore, but we are still uncertain how much of their production derives
from epiphytes versus the eelgrass. Therefore, most trophic linkages in seagrass communities are at
the secondary or higher consumer levels, i.e. predators feeding on herbivores or detritivores. A good
example of this is the abundance and availability of certain prey that are attached to eelgrass, for
instance the caprellid amphipods that shiner perch (Cymatogasteraggregata) feed upon extensively
(Caine 1980). As an example closer to this region, we have found in our studies of eelgrass communi-
ties in Padilla Bay (Simenstad el at. 1988) that specific taxa of harpacticoid copepods (e.g.,
Harpact/cus un/remis 4 , Zaus spp.), which are essentially unique to the eelgrass epiphyte assemblage,
are the principal prey items of juvenile chum salmon (Oncorhynchus keta), Pacific herring, Pacific
sand lance (Ammodytes hexapterus) and surf smelt (Hypomesus pretiosus). All these fishes are of
either commercial or ecological (i.e. as prey of economically important species) value in the Pacific
Northwest.
Refuge from predation is a function of the structural complexity of seagrass habitats, which is
superior to all but kelp forests among estuarine and nearshore marine communities, and in terms of
microhabitats, may also exceed kelp forests. The structural complexity of the seagrass and associ-
ated macro- and microalgae, bryzoans, hydroids, and other epifauna and epiflora inhibits the success
rate of predators that are unwilling or ineffective feeders within the habitat as compared in unvegetated
or less vegetated communities. Although rarely tested, this is likely the primary explanation for the
predominance of juvenile fishes (numerically, if not gravimetrically) in the fish assemblages of
seagrass communities in the Pacific Northwest (e.g. Miller et al. 1980) and other comparable regions
(Heck and Orth 1980; Orth and Heck 1980). Heck and Thoman (1981) provide one of the few explicit
indications that predation rates (on grass shrimp, Palaemonetes pugio, by killifish, Fundulus
hereroclitus) are mediated by seagrass (turtlegrass, Thalassia festud/num).
Physiological mechanisms for seagrass habitat use by consumers are more speculative.
Habitat use is assumed to be tied to the maintenance of lower and narrow ranges of temperature and,
at least during daytime, higher concentrations of dissolved oxygen (Phillips 1984). Many organisms
also may not be able to tolerate direct light intensities that would otherwise be present in these shallow
water habitats without the shading influence of seagrasses.
These four mechanisms for consumer-specific reliance on the seagrass habitat are highly
interrelated, however, and no one mechanism is uniquely responsible. For example, at least during
their juvenile stages, if not throughout their life history, certain fishes may be highly adapted (morpho-
logically as well as behaviorally) to feed on specific seagrass prey fauna, as they minimize mortality by
4 Since these studies, we have found H. un/rem/s abundantly associated with other epiphyte or epiphyte-like (e.g., diatom
mat) microhabitats in other habitats; but, in many estuaries eelgrass epiphytes are the predominant location for these
assemblages.

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14 - Sea grass Science and Policy
seeking refuge within the seagrass habitat from predators outside (e.g., Pollard 1984). And, the
“optimal” consequences (e.g., energy available for growth and reproduction) of foraging are linked
directly to the amount of time and energy these fishes must expend avoiding the predator, as well as
the energetic expenditures involved in preying upon organisms with different spatial distributions within
and outside the habitat and their avoidance capabilities (Townsend and Winfield 1985). To some
degree, water temperatures and dissolved oxygen levels will also influence the amount of energy
which can actually be assimilated into somatic or gonadal tissue. Thus, given the aggregate and
interrelated evolutionary influences on morphological, behavioral and life history traits of consumers
we find characterizing the eelgrass community today, it is impossible to relate their dependence upon
the habitat to any one particular attribute of the eelgrass habitat or community. Instead, we must
examine particular seagrass functions (e.g., “fish nurseries”) as the integrated consequence of the
evolution of both seagrasses and estuarine and nearshore marine fauna, i.e., the coevolution of the
community constituents. It is also important to remember that seldom, if ever, have scientists empiri-
cally established the fitness benefit of consumer organisms’ use of seagrass habitats, e.g., in terms of
survival to reproduction. At present, we must simply use the descriptive nature of the diverse, com-
plex assemblages of organisms and predator-prey interactions that characterize seagrass communi-
ties (Fig.1) as evidence for a highly co-evolved and “interdependent” community.
Challenges to Seagrass Science and Policy
As with any complex ecosystem with which our culture interacts, effective management of
seagrass communities demands both a comprehensive understanding of the basic biology of
seagrasses (the elemental building block of the habitat) and other biota in the community, and an
applied science knowledge of the community’s responses to natural and anthropogenic stresses.
Compared to analogous communities, terrestrial as well as marine, policy and management decisions
involving seagrasses and natural resources that depend upon this community are severely limited by
the immature state of basic and applied science. The challenge to increase our understanding of
seagrass communities, and their role in estuarine ecosystems, may seem mundane. However,
understanding the role of seagrass communities in fundamental ecosystem processes is not a trivial
objective, and has generally not been achieved beyond the descriptive or conceptual stage.
Integration of seagrass science and policy in the coming years will require:
(1) assessing the significance of utilization and extended residence in seagrass
habitats to the growth and survival of fishes and macroinvertebrates that occupy
seagrass as nursery habitats;
(2) determining the relationship between various structural and spatial aspects of
seagrass habitats and basic functions such as fish and macroinvertebrate utilization,
e.g., variation of fish and macroinvertebrate foraging as a function of plant density and
standing stock, blade width, patch size, epiphyte composition and standing stock, etc.;

-------
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Figure 1. Composite food web characteristics. Protected sandleelgrass, shallow sublittoral habitats in northern Puget Sound and the Strait of Juan de Fuca (from Simenstad et al.
1979).
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16 - Seagrass Science and Policy
(3) tracing the contribution of seagrass-generated organic matter to food web path ways
beyond the seagrass community, and in particular in the deep subtidal portion of
estuaries and inland seas that are the likely depositories of eelgrass detritus (Appendix,
page 17);
(4) assessing the influence of seagrass patch structure (e.g., size, configuration, edge, areal
aspect ratio, etc.) on both endogenous and exogenous processes and functions; and,
(5) determining the rate of herbivory specifically on the seagrass, both from macroherbivores
(e.g., water fowl) and microherbivores (e.g., isopods).
Conclusions
Much, if not the majority, of direct faunal associations can be tied to the physical structure of
seagrasses rather than direct biotic (i.e., as a result of the plants’ autotrophic processes) interactions.
Perhaps one of the most important attributes of seagrasses, at least with Zostera marina in the Pacific
Northwest region, is the structural complexity and food resources provided by epiphytes attached to
seagrasses. A unique aspect of seagrasses is that they are annually providing new substrate which
develops a complex and changing microhabitat of diatoms, macroalgae, bryozoans, hydroids and
other flora and fauna. The incredible productivity of the combined eelgrass/epiphyte autotrophic
assemblage is not only responsible for a richly complex habitat and secondary production of consum-
ers within the habitat but also for the entrapment of organic matter that can decompose and enter food
webs within the habitat. However, perhaps the most important biotic function of eelgrass on the scale
of entire estuaries or coastal ecosystems is in exporting organic matter that supports secondary
productivity in other habitats through detritus-based food webs (Appendix, page 17). While we have at
least qualitatively documented many of the intrahabitat (i.e. “community”) relationships, and especially
food web structure, we have yet to evaluate the broader (i.e. “ecosystem”) importance of seagrass
habitats to other communities in the coastal region.
Literature Cited
Caine, E. A. 1980. Ecology of two littoral species of caprellid amphipods (Crustacea) from Washington, U.S.A.
Mar. BioL 56: 327-335.
Heck, K.L., Jr., and R.J. Orth. 1980. Seagrass habitats: The roles of habitat complexity, competition and preda-
tion in structuring associated fish and motile macroinvertebrate assemblages. Pp. 449-464 in V.S. Kennedy
(ed.), Estuarine perspectives. Academic Press, Inc., New York. 533 pp.
Heck, K. L., Jr., and T. A. Thoman. 1981. Experiments on predator-prey interactions on vegetated aquatic
habitats. J. Exp. Mar. BIoL Ecol. 53:125-134.
Kikuchi, T. 1974. Japanese contributions on consumer ecology in eelgrass (Zostera marina L.) beds, with
special reference to trophic relationships and resources in inshore fisheries. Aquacult. 4:145-160.
Kikuchi, T., and J. M. Pérés. 1977. Consumer ecology of seagrass beds. Pp. 147-193 in C.P. McRoy and C.
Helfferich (eds.), Seagrass ecosystems: A scientific perspective. Marcel Dekker, Inc., New York. 314 pp.

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17 - Seagrass Science and Policy
Lindeman, A, L. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399-418.
Menge, B.A., and J.R Sutherland. 1976. Species diversity gradients: synthesis of the roles of predation,
competition and temporal heterogeneity. Am. Nat. 110:351 -369.
Miller, B. S., C. A. Simenstad, J. N. Cross, K. L. Fresh, and S. N. Steinfort. 1980. Nearshore fish and
macroinvertebrate assemblages along the Strait of Juan de Fuca including food habits of the common
nearshore fish. EPA-600/7-80-027, Interagency Energy/Environ. R& D Prog. Rep., Oft. Res. Dev., U.S.
Environ. Protect. Agency, Wash., D.C. 211 pp.
Orth, R. J., and K. L. Heck, Jr. 1980. Structural components of eelgrass (Zostera marina) meadows in the lower
Chesapeake Bay - Fishes. Estuaries 3:278-288.
Orth, A. J., K. L. Heck, Jr., and J. van Monfrans. 1984. Faunal communities in seagrass beds: A review of the
influence of plant structure and prey characteristics on predator-prey relationships. Estuaries 7: 339-350.
Phillips, R.C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: A community profile. FWS/OBS-
84/24, U.S. Fish Wildl. Serv., Biol. Sew. Prog., Wash., D.C. 85 pp.
Pollard, D.A. 1984. A review of ecological studies on seagrass - fish communities, with particular reference to
recent studies in Australia. Aquat. Bat. 18:3-42.
Simenstad, C. A. 1987. The role of Pacific Northwest estuarine wetlands in supporting fish and motile
macroinvertebrates: The unseen users. Pp. 29-35 in P. Dyer (ed.), Northwest Wetlands: What are they for?
For whom? For what? Proc. Northwest WetI. Conf., 1-2 Nov. 1985, Seattle, WA., Inst. Environ. Stud., Univ.
Wash., Seattle, WA. 253 pp.
Simenstad, C.A., and R.C. Wissmar. 1985. 3 C evidence of the origins and fates of organic carbon in estua-
rine and nearshore food webs. Mar. Ecol. Prog. Ser. 22:141 -1 52.
Simenstad, C. A., J. A. Cordell, R. C. Wissmar, K. L. Fresh, S. L. Schroder, M. Carr, G. Sanborn, and M. E. Burg.
1988. Assemblage structure, microhabitat distribution and food web linkages of epibenthic crustaceans in
Padilla Bay National Estuarine Research Reserve, Washington. FRi-U W-8813, Fish. Res. Inst., Univ.
Wash., Seattle, WA. 60 pp.
Townsend, C. R., and I. J. Winfield. 1985. The application of optimal foraging theory to feeding behavior in fish.
Pp. 67-98 in P. Tytler and P. Calow (eds.), Fish energetics: new perspectives. Croom Helm, London. 349 pp.
Wood, B. L. F., W. E. Odum, and J. C. Zieman. 1969. Influence of seagrass on the productivity of coastal
lagoons. Pp. 495-502 in Mem. Symp. Internat. Costeras (UNAM-UNESCO), 28-30 Nov., 1967.
Zieman, J. C. 1982. The ecology of seagrasses of south Florida: A community profile. FWS/OBS-82/85, U.S.
Fish Wildl. Sew., Biol. Sew. Prog., Wash., D.C. 158 pp.

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18 - Sea grass Science and Policy
Appendix: isotopes and Seagrasses
Indirect contributions to consumers may be difficult to detect, but are potentially more relevant to management
than direct feeding because they identify the connections between the seagrass and other communities,
perhaps even those that are not immediately adjacent to seagrasses; i.e., they establish the “waterscape”
ecology perspective. Some of the more obvious indirect contributions are tied into the role of seagrasses to
transient consumers, e.g., spawning sites for Pacific herring in Puget Sound that ultimately, after they have left
the seagrass habitats as larger juveniles, provide valuable prey resources for predators in coastal and open
ocean ecosystems across the entire North Pacific. Undoubtedly, the largest contribution of seagrasses external
to the habitat proper is the production and export of a tremendous amount of organic matter, both particulate
and dissolved, and may account for an extensive amount of the nearshor? fisheries production (e.g., Barsdate
et al. 1974). In that detritivores form most of the intermediary linkages in estuarine and coastal food webs, such
as in Puget Sound (Simenstad et al. 1979; Fig. 1), seagrass is likely the primary source to these detritus-based
food webs. For example, we are accumulating evidence using stable isotopes of carbon as “biomarkers” that
the organic matter generated by eelgrass and associated epiphytes are an important, and often dominant,
constituent in consumers in estuaries of Puget Sound (Simenstad and Wissmar 1985; Ruckleshaus 1988), In
Hood Canal, we found that the l 3 C signature of estuarine consumers were strongly influenced by the 13 C-
enriched autotrophs in the eelgrass habitat compared to the 13 C-depleted organic matter from terrestrial plants
or neritic phytoplankton. This “enrichment effect” may have even extended into marine littoral and neritic
consumers. In addition to the export of organic matter to food webs in other habitats, it must also be recog-
nized that the physical structure of seagrass habitats also accounts for trapping, and considerable consumption,
of organic matter that is transported into the habitat (Phillips 1984).
Literature Cited
Barsdate, A. J., M. Nebert, and C.P. McRoy. 1974. Lagoon contributions to sediments and water of the Bering
Sea. Pp. 553-576 in D. W. Hood and E. J. Kelly (eds.), Oceanography of the Bering Sea. PubI. 2, Inst. Mar.
Sci., Univ. Alaska, Fairbanks, AK.
Phillips, R. C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: A community profile. FWS/OBS-
84/24, U.S. Fish WildI. Serv., Biol. Serv. Prog., Wash., D.C. 85 pp.
Ruckelshaus, M. H. 1988. The effects of habitat characteristics on mussel growth in Padilla Bay, Washington.
M.S. thesis, Univ. Wash., Seattle, WA. 53 pp.
Simenstad, C. A., B. S. Miller, C. F. Nyblade, K. Thornburgh, and L. J. Bledsoe. 1979. Food web relationships of
northern Puget Sound and the Strait of Juan do Fuca: A synthesis of the available knowledge. EPA-600/7-
79-259, Interagency Energy/Environ. R&D Prog.. Rep., Off. Res. Dev., U.S. Environ. Protect. Agency,
Wash., D.C. 355 pp.
Simenstad, C. A., and A. C. Wissmar. 1985. 613C evidence of the origins and fates of organic carbon in estua-
rine and nearshore food webs. Mar. Ecol. Prog. Ser. 22:141-1 52.

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19 - Seagrass Science and Policy
3. Incorporating the Population Biology
of Eelgrass into Management
Maiy H. Ruckeishaus
Department of Botany, KB- 15
University of Washington
Seattle, Washington 98195
Eelgrass meadows are valuable estuarine and coastal habitats whose possible declines
(Thom and Hallum 1990) are prompting scientists and policy makers to reevaluate existing manage-
ment approaches. Seagrass management to date has focused on mitigation of habitat loss through
transplant projects. Transplantation of eelgrass as a restoration tool has had mixed success and, even
in cases where transplants survive, the functional equivalence of the restored and natural meadows
has not been established (Fonseca et al. 1988). Furthermore, consistent and reliable methods for
evaluating the success of restoration projects are not used. Therefore, our ability to evaluate the
effectiveness of different techniques is severely limited. By incorporating lessons from research in
population biology of natural plant populations, management approaches designed to protect and
restore seagrass systems can be greatly improved. In this paper, I discuss how insights from theoreti-
cal and empirical research in plant population biology can be used to address challenges facing
seagrass scientists and policy makers concerned with preservation of eelgrass systems.
Lessons from Population Biology
The sizes of eelgrass populations in nature are becoming smaller due to human-caused
fragmentation of natural beds and because logistical considerations limit the size of restored popula-
tions. As population size decreases, stochastic processes (e.g., loss of individuals or alleles, year to
year fluctuations in seed production) become more important. In addition, evolutionary theory sug-
gests that in smaller populations, the genetic composition of members has an increased influence on
population growth rate and persistence (Barrett and Kohn 1991). There is no empirical information
relating changes in eelgrass biology to changes in population size. It remains an important empirical
question whether changes in ecological (e.g., pollen and seed dispersal, seed production) or genetic
(e.g., mating system, number of alleles) attributes in small populations have a demonstrable effect on
eelgrass population growth rates or persistence. Results from such inquiries are critical for effective
design of restoration projects.
Independent of population size, the degree of patchiness will also affect a species’ persis-
tence. A major contribution from theoretical and empirical work in plant population biology is acknowl-
edgment of the difficulty in defining a “population”. In order to study the biotic and abiotic factors
regulating population size or growth rate, genetic and ecological criteria must be used in choosing a
“biologically relevant” group of interacting individuals. Eelgrass is often patchily distributed at a number

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20 - Sea grass Science and Policy
of spatial scales (i.e. within and among embayments), and the extent to which water-mediated dis-
persal creates connections among patches will ultimately determine the number of interacting individu-
als in a population and their response to
perturbation. Reproductive, morphologi-
cal, and genetic characteristics in LEAF WIDTH 1-3 mm
eelgrass are spatially patchy throughout % FLOWERING 1-4
ALLELE FREQUENCIES: unknow,,
its range in the Northeastern Pacific (Fig.
1). Ecological characteristics such as
leaf width and the incidence of flower Bering
and seed production vary dramatically,
even within Pacific Northwest estuaries
(Phillips et at. 1983, Backman 1991,
Ruckelshaus 1994). In studies of the Puget Sound-
distribution of genetic variation in Pacific Ocean
eelgrass among and within embayments
in Puget Sound, I have found significant
differences in the genetic composition
among patches within a bay and be-
tween bays (Ruckelshaus 1994; Fig.1).
For ecological attributes that
are genetically based, differentiation _________________________________________________
among patches may increase their Figure 1. Ecological and genetic differentiation In eelgrass
(Zostera marina) populations of the Northeast Pacific. Leaf width
isolation and affect the persistence of and percent flowering data are from Phillips et al. (1983), Backman
(1991), and Ruckelshaus (1994). Allele frequencies represent the
eelgrass populations. I found evidence for range in frequency of the most common allele (mean of five polymor-
genetically based ecological differences plucloci) among 20 patches in northern Puget Sound (Ruckeishaus,
between habitats in a study in which I
transplanted seeds between tide zones within a bay in the San Juan archipelago. Seeds did not
germinate well when planted into a “foreign” tide zone as compared to germination rates in their
“home” tide zone (Ruckelshaus 1994). This evidence for local adaptation points to the need for
attention to both donor and site characteristics when designing eelgrass restoration projects.
Intertidal eelgrass populations are often dynamic, and in many habitats, high rates of patch
turnover should be expected to occur under natural conditions. As long as recolonization of suitable
habitat keeps pace with disappearance of patches, populations in highly disturbed environments will
persist. In eelgrass populations with a high incidence of sexual reproduction, the availability of suitable
but unoccupied habitat may limit successful colonization of new populations in the face of local patch
extinction. In addition, high rates of patch turnover due to physical and biotic disturbance can over-
whelm any effect of ecological and genetic characteristics of patches or their persistence
2-20 mm
2-80 %
0.13-0.92
LEAF WIDTH
S FLOWERING

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21 - Seagrass Science and Policy
(Ruckelshaus 1994). Monitoring of eelgrass populations should take into account not only the disap-
pearance of existing patches, but also the rate of occurrence of newly colonized areas.
Challenges Facing Seagrass Scientists and Policy Makers
A major challenge facing scientists concerned with eelgrass habitat protection is to determine
which aspects of eelgrass biology are critical to population persistence. Clearly, existing approaches to
eelgrass management do not incorporate enough information about ecological and genetic factors
affecting population growth. Our research priority should be to find the most parsimonious combination
of biological details needed for predicting population growth and survival. For managers whose task
includes isolation and prevention of numerous potential causes of eelgrass declines, the simpler the
model of factors affecting the health of eelgrass populations, the better. We do not have the luxury in
time or resources to fine-tune an eelgrass policy by incorporating extraneous ecological or genetic
factors with no demonstrable effects on eelgrass persistence. An explicit demographic analysis of
population growth rates and factors limiting life history stage transitions is needed (Schemske et al. in
press). We can only address this need with rigorous experimentation and documentation of how
variation in life history characteristics, morphology and genetic composition of individuals affect the
demography of eelgrass populations.
An important gap in eelgrass policy is the lack of attention paid to the effects of natural
population and patch dynamics in monitoring designs. The high rates of patch turnover characteristic
of many (especially intertidal and disturbed subtidal) habitats necessitate that both existing and
available, but unoccupied, patches be censused regularly. In this way, eelgrass habitat can be more
appropriately defined as all suitable sites, occupied or not. For inventory purposes and in monitoring
the changes in demography of restored and natural populations, a focus on the whole landscape is
critical. Finally, because ee!grass populations in the eastern Pacific Ocean have a unique genetic and
demographic history as compared to those in the Gulf of Mexico or the Western Atlantic Ocean, policy
aimed at protecting Pacific populations of eelgrass should be guided by biological information obtained
from those same populations. In addition to the striking physical (e.g., slope of continental shelf, tidal
range and periodicity) and biological (e.g., competitors, herbivores, parasites) contrasts between the
ocean basins, the Pacific and Atlantic populations have had historically different population size
fluctuations. For example, the Atlantic eelgrass populations have experienced a number of docu-
mented catastrophic declines over the past century due to a “wasting disease” (Muehlstein 1989).
Such periodic bottlenecks in population size result in dramatic changes in genetic composition, none
of which have been documented in Pacific populations despite the presence of disease symptoms
(Short et al. 1987, Muehlstein et al. 1988).

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22 - Sea grass Science and Policy
Literature Cited
Backman, T.W.H. 1991. Genotypic and phenotypic variability of Zostera marina on the west coast of North
America. Can. J. Bot. 69:1361-1371.
Barrett, S.C.H., and JR. Kohn. 1991. Genetic and evolutionary consequences of small population size in plants:
Implications for conservation. Pp. 3-30 in D.A. Falk and K.E. Holsinger (eds.), Genetics and conservation
of rare plants. Oxford Univ. Press, NY.
Fonseca, M.S., W.J. Kenworthy and G.W. Thayer. 1988. Restoration and management of seagrass systems: a
review. Pp. 353-368 in D. D. Hook et al. (eds.), The ecology and management of wetlands. Vol. 2, Manage-
ment, use and value of wetlands. Timber Press, OR.
Muehlstein, L.K. 1989. Perspectives on the wasting disease of eelgrass, Zost era marina. Diseases of Aquatic
Organisms 7:211-221.
Muehlstein, L.K., D. Porter and F.T. Short. 1988. Labyrinthula sp., a marine slime mold producing the symptoms
of wasting disease in eelgrass, Zostera marina. Mar. Biol. 99:465-472.
Phillips, R.C., W.S. Grant and C.P. McRoy. 1983. Reproductive strategies of eelgrass (Zostera marina L.) Aquat.
Bot. 16:1-20
Ruckelshaus, M.H. 1994. Ecological and genetic factors affecting population structure in the marine
angiosperm, Zostera marina L. Ph.D. Dissertation, University of Washington, Seattle, WA.
Schemske, D.W., B.C. Husband, M.H. Ruckelshaus, C. Goodwillie, l.M. Parker and J.G. Bishop. 1994.
Evaluating approaches to the conservation of rare and endangered plants. Ecology (in press).
Short, F.T., L.K. Muehlstein and D. Porter. 1987. Eelgrass wasting disease; cause and recurrence of a marine
epidemic. Biol. Bull. Mar. Biol. Lab, Woods Hole 173:557-562.
Thom, R.M., and L. Hallum. 1990. Long-term changes in the aerial extent of tidal marshes, eelgrass meadows
and kelp forests of Puget Sound. Final report to U.S. Environmental Protection Agency. Fisheries
Research Institute, University of Washington, Seattle. EPA 910/9-91-005.

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23 - Sea grass Science and Policy
4. Light Environments/Implications for Management
Douglas A. Bulthuis
Washington State Department of Ecology
Pad/I/a Bay National Estuarine Research Reserve
1043 Bayview Edison Road
Mount Vernon, Washington 98273
The light requirements of seagrasses are often an overlooked factor in the management of
bays and estuaries. In this article I will outline some evidence that (1) seagrasses need light, (2) their
lower depth limit is controlled by light, (3) increased suspended sediments and phytoplankton in the
water reduce light to seagrasses, (4) increased growth of epiphytes reduces light to seagrasses, and
(5) many of the major losses of seagrasses throughout the world have been attributed directly or
indirectly to reduced light.
Seagrasses require sufficient light for growth and survival, but seagrasses near the lower
depth limit within any estuary or bay are often restricted in their growth and distribution by lack of light.
Loss of water clarity reduces the depth penetration of seagrasses, making large areas of subtidal
habitat unsuitable for growth. These changes are rarely seen or reported because they occur at the
deeper end of the distribution of seagrasses and not in the intertidal where changing distribution
patterns are more easily observed. The losses can occur slowly and incrementally. However, their
net effect in eliminating seagrass is just as effective as when habitat is dredged, filled or shaded by a
nearshore structure.
The lower limit of distribution of seagrasses is often controlled by the amount of light. The
importance of light has been demonstrated experimentally (Backman and Barilotti 1976, Bulthuis
1983, Dennison 1987) and in surveys of the lower depth limit of seagrasses. Duarte (1991) has
reviewed many surveys of seagrass distribution and measurements of light at the lower depth limits.
Based on these surveys, Duarte suggested that about 20% of the surface light is required for survival
of Zostera marina. Almost all of these surveys were conducted outside the Pacific Coast of North
America. However, they represented widespread geographic areas and there was close agreement in
the percent light measured at the lower depth limit. Management of Zostera marina on the Pacific
Coast of North America should focus on ensuring that 20% of incident light reaches the desired lower
limit of eelgrass distribution.
The requirement of seagrasses for clear water above them for light transmission makes
management more complex. Light transmission in estuaries and bays may be reduced by suspended
sediments, phytoplankton, and/or dissolved organic material. The concentration of these materials is
dependent on a variety of management activities, including clearing of forested watersheds, dredging
in the bays, discharge of municipal wastewater, runoff from agricultural fields, and storm water runoff.
Phytoplankton growth and biomass may increase when the supply of nutrients is increased. As

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24 - Sea grass Science and Policy
nutrient supply increases, phytoplankton biomass may increase, and the increased biomass (usually
measured as concentration of chlorophyll) absorbs more of the light before it reaches the seagrasses.
Thus, management becomes more complex because so many factors need to be considered and
controlled.
Nutrient increases affect epiphytes of eelgrass as well as phytoplankton. When epiphyte
growth is stimulated by water borne nutrients, the biomass of epiphytes can shade the eelgrass leaf to
which it is attached and reduce the time that a leaf of eelgrass can have positive net photosynthesis
(Bulthuis and Woelkerling 1983). The nutrient-epiphyte-eelgrass relationship is further complicated by
the interaction between grazers and epiphytes. If grazer density is high enough, epiphyte grazers can
keep the biomass of epiphytes low in spite of high nutrient supply (Orth and Van Montfrans 1984,
Williams and Ruckelshaus 1993). Understanding the effect of grazers on epiphyte biomass has been
important in explaining the survival of eelgrass in some areas where nutrient supply is high and growth
of phytoplankton and epiphytes would have been expected to kill the eelgrass through light reduction.
The importance of light to seagrasses is illustrated by major losses of around the world, where
reduced water clarity has been identified as a major cause. The loss of most submerged aquatic
vegetation from Chesapeake Bay was attributed to the increased suspended sediments and nutrients
that reduced water clarity and increased growth of epiphytes (Orth and Moore 1983, Kemp et al. 1983,
Dennison et al. 1993). In the Dutch Wadden Sea, huge areas that formerly supported growth of
eelgrass are now bare, apparently because suspended sediments made the light climate unsuitable
(Giesen et al. 1990). In Western Port, Victoria, Australia, more than two-thirds of the seagrasses
declined over a 10 year period, apparently because the suspended sediments settled on the leaves
blocking light (Shepherd et al. 1989). In that case, the loss of seagrass resulted in erosion of mud
banks leading to increased suspended sediments and further losses of seagrass. Here on the west
coast of North America the very limited distribution of seagrass in San Francisco Bay appears to be a
result of the low water clarity in the bay (Wyllie-Echeverria 1990, Zimmerman etal. 1991). These
examples all indicate the importance of light to seagrass, the vulnerability of seagrass to factors that
decrease light, and the need to place greater emphasis on water clarity to protect and enhance
seagrass on the west coast of North America.
The light requirements of seagrasses and the many factors included in determining the light
climate of the eelgrass leaf (such as suspended sediment, phytoplankton, nutrients, and epiphytes)
emphasize the importance of watershed management if eelgrass are to survive. The Chesapeake
Bay management committee recognized the integrating role of eelgrass and other submerged aquatic
vascular plants as an assessment of water quality in Chesapeake Bay (Fig.1). Efforts to improve
water quality in various parts of the estuary will be judged by whether aquatic plants, including eel-
grass, survive and become re-established in areas of suitable substrate. The specific water quality
criteria developed in Chesapeake Bay may not be helpful on the west coast, but the watershed and

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25 - Sea grass Science and Policy
Light
Water
DIN
I
DIP
Chlorophyll a
Total
suspended
solids
Particles
Water column
light
attenuation
(Kd)
Leaf surface
light
attenuation
Figure 1. Dynamics of light attenuation in nearshore seagrass communities (Dennison et al. 1993). Availability of light for submersed
aquatic vegetation (SAV) is determined by light attenuation processes. Water column attenuation, measured as the light attenuation coeffi
cient (Kd), results from absorption and scatter of light by particles in the water (phytoplankton, measured as chlorophyll a, and total organic
and inorganic particles, measured as total suspended solids) and by absorption of light be water itself. Leaf surface attentuation, largely due
to algal epiphytes growing on submersed leaf surfaces, also contribute to light attenuation. Dissolved inorganic nutrients (DIN, dissolved
inorganic nitrogen; DIP, dissolved inorganic phosphorus) contribute to phytoplankton and epiphyte components of overall light attenuation,
and epiphyte components of overall light attenuation, and epiphyte grazers control accumulation of epiphytes.
Epiphytes
Ir
Graze

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26 - Seagrass Science and Policy
ecosystem approach is important, and such an approach should be used on the west coast to main-
tain and improve water clarity in order to protect and enhance growth of eelgrass.
One of the major challenges to seagrass science and policy in the coming years is to develop
meaningful criteria for water clarity that will preserve and enhance growth of eelgrass. Water clarity is
highly variable in time and space and affected by many different factors. Ease of measurement and
biological relevance are not always compatible. Once having selected meaningful criteria, seagrass
science and policy will face the challenge of integrating the requirements for seagrasses with other
aspects of watershed and ecosystem management without losing the relevance for eelgrass.
Important publications that could inform and/or direct seagrass management in western North
America include Ron Phillips’ 1984 review of Pacific Northwest eelgrass communities based in part on
his 1972 thesis (one of the first major descriptions of eelgrass on the west coast). A second important
publication is Duarte’s (1991) review of seagrass depth limits and the light environment at those
depths. Dennison (1987) reviewed the light requirements of seagrasses and Cambridge et. al. (1986)
studied the links between increased nutrients, increased epiphytes, and a major loss of seagrasses.
The publication by Dennison et al. (1993) is important not so much because of the specific water
quality criteria they developed, but because of the ecosystem-wide approach that was taken and the
attempts to set specific measurable goals regarding growth of aquatic plants in specific areas.
Literature Cited
Backman, T. M., and D.C. Barilotti. 1976. Irradiance reduction: effects on standing crops of the eelgrass
Zostera marina in an coastal lagoon. Mar. Biol. 34:33-40.
Bulthuis, 0. A. 1983. Effects of in situ light reduction on density and growth of the seagrass Heterozostera
tasmanica (Martens ex Aschers.) den Hartog in Western Port, Victoria, Australia. J. Exp. Mar. Biol. Ecol.
67:91-103.
Bulthuis, D. A., and W. J. Woelkerling. 1983. Biomass accumulation and shading effects of epiphytes on
leaves of the seagrass, Heterozostera tasmanica, in Victoria, Australia. Aquat. Bot. 16:137-148.
Cambridge, M.L., A.W. Chiffings, C. Brittan, L. Moore, arid A. J. McComb. 1986. The loss of seagrass in
Cockburn Sound, Western Australia. II possible causes of seagrass decline. Aquat. Bot. 24:269-285.
Dennison, W. C. 1987. Effects of light on seagrass photosynthesis, growth and depth distribution. Aquat. Bot.
27:15-26.
Dennison, W.C., R.J. Orth, K. A. Moore, J. C. Stevenson, V. Carter, S. Kollar, P. W. Bergstrom, and A. A.
Batiuk. 1993. Assessing water quality with submersed aquatic vegetation. BioScience 43:86-94.
Duarte, C. M. 1991. Seagrass depth limits. Aquat. Bot. 40:363-377.
Giesen, W. B.J., M.M. van Katwijk, and C. Den Hartog. 1990. Eelgrass condition and turbidity in the Dutch
Wadden Sea. Aquat. Bat. 37:71-85.

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27 - Seagrass Science and Policy
Kemp, W.M., W.R. Boynton, R.R. Twilley, J.C. Stevenson, and J.C. Means. 1983. The decline of submerged
vascular plants in Upper Chesapeake Bay: summary of results concerning possible causes. Mar. Tech.
Soc. J. 17:78-89.
Orth, R.J., and K. A. Moore. 1983. Chesapeake Bay: an unprecedented decline in submerged aquatic vegeta-
tion. Science 222:51-53.
Orth, R. J., and J. van Montfrans. 1984. Epiphyte-seagrass relationships with an emphasis on the role of
micrograzing: a review. Aquat. Bot. 18:43-69.
Phillips, R.C. 1972. Ecological life history of Zostera marina L. (eelgrass) in Puget Sound, Washington. Ph.D.
dissertation, University of Washington. Seattle, WA. 154 p.
Phillips, R.C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: a community profile. U.S. Fish
WildI. Serv., FWS/OBS-84/24, 85 p.
Shepherd, S.A., A.J. McComb, D. A. Bulthuis, V. Neverauskas, D. A. Steffensen, and R. West. 1989. Decline
of seagrasses. Pp. 346-393 in A.W.D. Larkum, A.J. McComb, S.A. Shepherd (eds.), Biology of
seagrasses, a treatise on the biology of seagrasses with special reference to the Australian region.
Elsevier, Amsterdam.
Williams, S.L., and M.H. Ruckelshaus. 1993. Effects of nitrogen availability and herbivory on eelgrass (Zostera
marina) and epiphytes. Ecology 74:904-918.
Wyllie-Echeverria, S. 1990. Distribution and geographic range of Zostera marina, eelgrass in San Francisco
Bay, California. Pp. 65-69 in K.W. Merkel, and R.S. Hoffman (technical eds.), Proceedings of the California
Eelgrass Symposium. Sweetwater River Press, National City, California.
Zimmerman, R.C., J. L. Reguzzoni, S. Wyllie-Echeverria, M. Josselyn, and R.S. Alberte. 1991. Assessment
of environmental suitability for growth of Zostera marina L. (eelgrass) in San Francisco Bay. Aquat. Bot.
39:353-366.

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29 - Sea grass Science and Policy
MANAGEMENT ISSUES
5. Inventory of Seagrasses:
Critical Needs for Biologists and Managers
Thomas F Mum ford, r. 1
Botany Department, KB-15
University of Washington
Seattle, Washington 98195
‘Hard t’say without knowin”
D. Melvin
An inventory of a natural resource is the elucidation of the type, amount and location of that
resource, sometimes done on a one time basis (baseline) or several times to determine changes in
the type, location or amount of the resource (trend analysis). An inventory of all the resources in an
area is a synoptic inventory, the inventory of only one or a few resources is a thematic inventory.
Inventories are critical to good management of natural resources. Without knowledge of what is being
managed, policy development and planning are being carried out in the dark. This paper discusses
the inventory of Zostera marina, eelgrass, and Zostera japonica in the Pacific Northwest.
Inventories as Information System
Inventories should be viewed as information systems which create and maintain a spatial data
base and deliver useful information to the end users. This means that all activities should be coordi-
nated and planned. These activities are usually performed in this sequence:
A. Business Needs Analysis
B. System Design and Construction
C. Data Acquisition
D. Ground Truthing
E. Data Analysis
F. Data Storage
G. Product Delivery
H. Maintenance
I. Documentation on an ongoing basis
A detailed explanation of these nine points is provided in the Appendix, pages 31-35.
1 Current address: Division of Aquatic Lands, Department of Natural Resources, P0 Box 47027, Olympia WA 98504-7027.

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30 - Sea grass Science and Policy
Historical Inventories
Eelgrass has been inventoried in a variety of methods for the past 150 years. The earliest
records, incidental in nature, were navigational charts. “Grass” was indicated on the charts, especially
in harbors, until 1925 when the kelp and eelgrass symbols were combined (Thom and Hallum 1990).
Some of the earliest dedicated eelgrass surveys were done by Phillips, especially in Hood Canal.
These surveys, conducted in 1962-3, were accomplished by pulling Dr. Phillips, equipped with SCUBA
gear, underwater around Hood Canal. This effort remains one of the heroic inventory efforts of all
times. These data were only partially published (Phillips and Fleenor 1970).
Although there have been numerous regional or site-specific inventories (Phillips 1984), the
first state-wide inventory was performed by Washington Department of Natural Resources and pub-
lished as the “Washington Marine Atlas” in the early 1970’s. Information was collected from a variety
of sources dating from the 1960’s. The large scale and generalizations of the beds made it useful only
regionally. A second state-wide effort was begun in early 1970’s and published as the Washington
Coastal Zone Atlas (WCZA) (Washington Dept. of Ecology 1980). The information for eelgrass was
derived from 1:6,000 scale natural color aerial oblique photographs with the beds published at a scale
of 1:24,000 (Gardner 1984). The maps remain the most widely used in Washington. They are,
however, highly inaccurate, especially in the subtidal zone. Although information from the WCZA has
been digitized and re-published in the Puget Sound Environmental Atlas (Washington Dept. of Ecology
1980; PSWQA 1989; ESRI 1989), the eelgrass data have not been updated (PSWQA 1992). The
highest needs are for subtidal inventories. Losses near the lower limit of eelgrass are largely unknown,
yet this is the area most likely impacted by water quality degradation and reduced light penetration.
Another unpublished source of information regarding eelgrass in Washington comes inciden-
tally from the herring roe surveys performed for the last 50 years by the Washington Department of
Fisheries (WDF). WDF staff routinely raked subtidal spawning areas and noted the presence of
eelgrass, seaweeds and roe. These records have never been analyzed, but exist in numerous field
notebooks in Olympia.
Current Inventory Efforts
Under the guidance of the Puget Sound Water Quality Authority and its Puget Sound Ambient
Monitoring Program (Puget Sound Water QualityAuthority 1992), the Washington Department of
Natural Resources is inventorying the nearshore habitats of Puget Sound using remote sensing and
GIS to acquire, analyze and store the data (Mumford 1992). The primary purpose of this program is to
monitor habitats as indicators of the success or failure of water quality programs in Puget Sound. This
effort will inventory the entire shoreline of Puget Sound every three years. The project does not
include the Strait of Juan de Fuca nor the outer coast and its estuaries, Grays Harbor and Willapa Bay.
Eelgrass is one of the high priority resources to be mapped. This information will be useful to local
planners as they strive to meet the mandates of the Growth Management Act, and to the Department

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31 - Sea grass Science and Policy
of Natural Resources in its proprietary responsibilities for state-owned aquatic lands.
Two major federal inventory efforts are underway, Coastwatch (Thomas et al. 1991) and
EMAP (Hunsaker et al. 1990). Coastwatch is designed to specifically monitor changes in coastal
wetlands, including submerged aquatic vegetation (SAy). The method to be used for SAV monitoring
is aerial photography (Klemas et al. 1987). The use of underwater video to inventory subtidal eelgrass
beds is currently being investigated in a pilot project (Norris et al. 1994).
Changes in Distribution/Abundance
Spurred by the urgency of the situation in Chesapeake Bay (Orth and Moore 1983), Thom and
Hallum (1990) analyzed historical data to determine if there have been long term changes in the
distribution and abundance of kelp and eelgrass in Washington. They found reliable information only
for the major urbanized embayments and, not surprisingly, major losses primarily due to fill of tideflats
(70% loss in Bellingham Bay, 15% in the Snohomish River Delta, but interestingly, a five-fold increase
in coverage in Padilla Bay). This last increase may be even more dramatic because early records
show no eelgrass in this bay prior to the diking of the Skagit River (D. Bulthuis, pers. comm., 1993).
Summary
Eelgrass serves as an indicator of environmental health (den Hartog 1971) and the functions
associated with these plants (e.g. primary productivity, habitat, hydrodynamics) depend upon its
presence. Once a reliable baseline map is created, trends in eelgrass abundance can be assessed.
The greatest need is a subtidal inventory. Losses at the lower limit of eelgrass are largely
unknown, yet this is the area most likely impacted by water quality degradation and lower light pen-
etration (see Buithuis, ch. 4). It is ironic that perhaps the most threatened portion of the eelgrass beds
are those not being inventoried in any fashion at this time.
Having said this, it is important to note that the inventory of eelgrass is beginning to move
from its historical pattern of piecemeal, site-by-site efforts using a variety of methods, to one of creat-
ing an information system. A major challenge will be to create and use standard methods necessary
to allow comparisons between inventories.
An even more critical challenge will be to make sure the information is available to the users
(biologists, planners and site-managers). Interfaces between the information and the user will have to
be created. Updated information must be incorporated. All this will require a long-term commitment of
funds.

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32 - Sea grass Science and Policy
Literature Cited
den Hartog, C. 1971. The dynamic aspect in the ecology of seagrass communities. Conference Paper.
Thalassia Jugoslavica 7(1): 101-112.
ESRI. 1989. An analysis of the Puget Sound Environmental Atlas. Report prepared for the Puget Sound Water
Quality Authority. Environmental Systems Research Institute. Redlands, California.
Gardner, F 1984. Washington’s Coastal Zone Atlas. American Society of Photogrammetry, Falls Church, VA.
Hunsaker, C., D. Carpenter, et al. 1990. Ecological indicators for regional monitoring. Bull. Ecol. Soc. Amer.
71 (3):165-1 72.
Klemas, V. J., J. Thomas and J.B. Zaitzeff (eds.). 1987. Remote sensing of estuaries - Proceedings of a
workshop. U.S. Dept. of Commerce, NOAA and U.S. Government Printing Office, Washington, D.C.
Mumford, T. F. 1992. Protocol for the inventory and monitoring of Puget Sound nearshore habitats. Puget
Sound Water Quality Authority and U.S. Environmental Protection Agency.
Norris, J., S. Wyllie-Echeverria, 1. Mumford and A. Bailey. 1994. Nearshore subtidal seagrass mapping using
automated analysis of underwater video images, p. 598. Proceedings of the Second Thematic Conference,
Remote Sensing for Marine and Coastal Environments. Vol. I. Environmental Research Institute of
Michigan, Ann Arborn, Ml, 704 pp.
Orth, R.J., and K. A. Moore 1983. Chesapeake Bay: An unprecedented decline in submerged aquatic vegeta-
tion. Science 222:51-53.
Phillips, R.C., and B. Fleenor 1970. Investigation of the marine flora of Hood Canal, Washington. Pac.
Sd. 24:275-281.
Phillips, R.C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: A community profile. U.S. Fish
and Wildlife Service. FWS/OBS-84/24.
Puget Sound Water Quality Authority (PSWQA). 1989. Recommendations on developing a geographic informa-
tion system for Puget Sound and updating the Puget Sound Atlas. Puget Sound Water Quality Authority,
Olympia, WA 43 p.
Puget Sound Water Quality Authority. 1992. 1992 Puget Sound Water Quality Authority Plan. Puget Sound
Water Quality Authority, Olympia, WA.
Thom, R.M., and L. Hallum. 1990. Long-term changes in the areal extent of tidal marshes, eelgrass meadows
and kelp forests of Puget Sound. Wetland Ecosystem Team, Fisheries Research Institute, University of
Washington. FRI-UW-9008 to the U.S. Environmental Protection Agency, Region 10.
Thomas, J. P. et al. 1991. NOAA’s Coastwatch: Change Analysis Program. American Society of Civil
Engineers, New York.
Thomas, J.P., R.L. Ferguson, J.E. Dobson and FA. Cross. 1991. NOAAs coastwatch: change analysis
program, coastal wetlands. Coastal Zone ‘91 Conference ASCE, Long Beach, CA, pp. 259-267.
Washington State Department of Ecology. 1980. Coastal Zone Atlas of Washington. Automated database: An
introduction.
Webber, H.H., T.F. Mumford, and J. Eby. 1987. Remote sensing inventory of the seagrass meadow of the Padilla
Bay National Estuarine Research Reserve. Areal extent and estimation of biomass. Report to NOAA/
OCRM/MEMD by Western Wash. Univ., Huxley College of Environmental Studies. 70 pp. Bellingham, WA.
Padilla Bay National Estuarine Research Reserve Reprint Series No. 6, 1990.

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33 - Sea grass Science and Policy
Appendix: Inventories as Information Systems
A. Business Needs Analysis
1) Define the “job” to be done with the Information. Some examples are:
a. Data for biological modeling of primary production, habitat functions, hydrodynamics, sediment
stabilization, wave attenuation, or community analysis.
b. Assist in siting, regional planning and cumulative impact assessment.
c. Trend analyses. Trends may be both on a temporal and/or spatial basis.
2) Determine what information and quality of information is needed to do the “job”
a. Spatial accuracy
i. Minimum mapping unit- the smallest area for which data are collected, analyzed and stored.
This involves an interplay between the scale and resolution.
ii. Positional accuracy of the information
Absolute accuracy - position in relation to the earth coordinate (latitude/longitude or UTM projection
coordinates)
Relative accuracy - the ability to distinguish between different vegetation types (e.g., eelgrass vs.
ulvoids, or mixtures of the two) and positioning the line drawn between them. The need will
determine what measurement system may be used: traditional surveying, global positioning
satellites (GPS), radio location, etc. as well as classification and analysis methods.
b. Temporal accuracy
i. When data are collected
Seasonal variation in the abundance and types of vegetation, particularly in temperate
climates; maximum standing crop or maximum growth rate; and degree of fouling by epi-
phytes all must be considered.
ii. How often data are collected.
Changes in maximum standing crop may also require data collection several times a year
(multi-temporal) in order to distinguish between vegetation types, e.g., eelgrass beds tend to
maintain a high standing crop year-round while ulvoids and other algae may only present
during the summer.
c. Trend analysis
Change in eelgrass bed position, abundance, or species composition. Measurement of these
changes is difficult. Inter-annual variation caused by natural phenomena, (El Nina, winter
freezes, etc.), are important and make any base-line done on a one-time basis suspect.
“Directional” changes may be caused by intrinsic vegetation changes (succession), land-use
and other human caused changes, or changes in global climate patterns and sea level
changes. Distinguishing one from another is difficult.
d. Tidal height, wave height
e. Water clarity
f. Classification
US Fish and Wildlife Service (Cowardin et aL 1979) Is most often used.
g. Definition of an eelgrass “bed”
“Greater than 40 turions/m 2 ” -Washington definition
The definition of Z japonica beds has not been made. These two species may overlap in their
range in the mid-intertidal.

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34 - Seagrass Science and Policy
h. Accuracy (Congalton 1991, Lunetta, Congalton et al. 1991)
i. Overall accuracy of the Multispectral Scanner (MSS) classification is given by the sum of
the total correct (numbers in the major diagonal) divided by the total number of pixels
checked for accuracy.
ii. Producer’s accuracy is the probability of a reference pixel being correctly classified by
the MSS classification. Producer’s accuracy is calculated for each class. A person
looking at an eelgrass bed on the water knows that there is a certain chance that bed
is correctly identified on the map as eelgrass.
iii. User’s accuracy is the probability that a pixel on the map actually represents what is on
the ground. A person looking at an area mapped as eelgrass knows that there is a
certain chance that there is actually eelgrass on that site.
i. Extent
i. Horizontal (geographical area)
site specific, regional, or state-wide, or national?
ii. Vertical extent
intertidal
subtidal
both?
j. Who will be using the information and what products will they need?
B. System Design and Construction
Once the business needs assessment is completed and agreed upon, the rest of these tasks
become much easier and should be turned over to a team of specialists. There should now be
concrete criteria for performance and system design, rather than being a guessing game built on
unknown assumptions.
C. Data Acquisition
The method of acquisition of the field data used will depend upon the criteria already discussed. In
addition, factors such as cost, availability of aircraft, weather, etc. must be considered.
Ground-based acquisition can be accomplished using boats or on foot. In a sense, it is remote
sensing of the resource, but the scale between the eelgrass and eye is only a few meters and the
beds are observed and interpreted directly onto a base map or photo. Because of the spatial
placement of the beds, accurate mapping of extent is difficult, although there is seldom any rnisin-
terpretation of eelgrass vs. some other vegetation (high classification accuracy but low spatial
accuracy). The use of hand-held, continuously-recording global positioning satellite (GPS) units
can be used to delineate beds. The base map or photo must be rectified, i.e. have accurate
positional marks. The use of unrectified photographs is not advised if the information is to be
transferred into a digital database (GIS). Either Ortho-photos (scale of 1:12,000), available from
Department of Natural Resources, 2 or USGS quadrangle maps (scale of 1:24,000 7.5) should be
used.
Methods for the use of transects to determine turion density and community structure is discussed
in Orth and Moore (1983).
Remote sensing data are recorded on film, digital tape or videography, and then analyzed and
classified. The data recorder can be mounted on a ground-based platform (tall pole, crane, kite,
tethered balloon or dirigible) or free-flying (remote-controlled aircraft, ultralight, manned aircraft,
satellite).
The data can be recorded photographically, digitally, or by videography. Photography is the time-
tested method and techniques are well established (Orth and Moore 1983). Different film types are
used for different applications. Black and white film is seldom used. It is not significantly cheaper
2 AvallabIe from: Photo and Map Sales, Department of Natural Resources, Natural Resource Building, 1111 S. Washington St.
Olympia, WA 98504

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35 - Sea grass Science and Policy
and there is less information in shades of gray than in colors. Natural color film is widely used. It provides
good water penetration so shallow subtidal beds can be seen although eelgrass on dark substrate may be
difficult to distinguish. False-Color infrared film is widely used in vegetation mapping because chlorophyll-
containing plants appear red. This makes distinguishing vegetation easy. Its main limitation is water
appears black and there is no or very little (only if overexposed) water penetration.
Widely used film formats include 35mm (true false-color infrared film not available), 70mm and 9” aerial
photographic film. There is a tradeoft between cost and the ability to see small detail in these films.
Cameras are usually used in ground-based systems or aircraft. The issue of oblique vs. vertical photogra-
phy should be discussed. Flying along a beach and taking photos out the window may enable one to easily
distinguish eelgrass beds, but it is very difficult, in fact nearly impossible, to rectify the image to project it on
a vertically-based map without ground control points in the image.
The ability to quickly and cheaply digitally scan photographs has increased dramatically in the last few
years. Film remains a inexpensive way to acquire and store enormous amounts of information in compari-
son to direct digital methods discussed below. But the ability to manipulate digital images is so powerful
that many want to have that option.
The direct acquisition of digital data can be accomplished by imagers mounted in aircraft or satellites.
Aircraft have the advantage of being able to fly at a particular time, i.e. during clear weather and low tides.
The resolution of the imagery can be varied by the height of the aircraft. The cost, however, is higher than
satellite imagery.
Satellite imagery is obtained commercially from Landsat or SPOT. Resolution (pixel size) for Landsat TM
data is 30m and 20m for SPOT. The main drawbacks to satellite imagery are high cost, low resolution, and
availability (TM satellites only pass over the study area every 17 days and trying to get a clear day and low
tide during the summer growing season is difficult (Webber et al. 1987). In general, the minimum mapping
unit is a 3x3 pixel unit (90m on a side or nearly a hectare (2.5 acres)). Strip eelgrass beds only 3-lOm wide
may not be visible in this imagery. The data are usually well georeferenced, however.
The type of sensor is also important, not only for pixel size, but also for geometry and hence ability to
georeference the image, and derive spectral resolution. Scanners such as those made by Daedelus
acquire each pixel sequentially and thus each pixel has a separate geometry, making georeferencing nearly
impossible. Pushbroom scanners have similar line geometry, making georeferencing easier. Chips such as
the charge couples device (CCD) have a three dimensional geometry, similar to photographs and can be
georeferenced in a similar manner. Each device has a different number of spectral channels, some of
which can be changed.
Videography has the advantage of being very inexpensive in comparison to other scanners. Commercially
available equipment can be used. Commercial true-color cameras can be mounted in a variety of plat-
forms, and multi-camera arrays for multichannel acquisition are available. Frame-grabbers can be used to
transfer data into image processing software. Videography has been used with underwater sleds or
platforms (Jim Norris, pers. comm.). Side scan sonar has also been used to map underwater vegetation. A
major problem has been the ability to ground truth the information and to determine if the images are truly
eelgrass or kelp.
D. Ground Truthing
Ground truthing is an integral part of any remote sensing inventory. First, it is essentially the verification
process to check the accuracy of information. Second, ground truthing information is gathered for training
sets in computer analytical procedures or for training of photointerpreters. The same data must not be used
for training and accuracy assessment. Sample size is discussed in Congalton (1991).
E. Data Analysis
PhotointeipretatiOfl
Photographic images are visually inspected and the eelgrass beds marked either on the photo or in direct
digitization. The use of stereoscopic pairs of photographs, in spite of the very low relief of the features, add
important texture to the image, making identification easier.

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36 - Sea grass Science and Policy
Computer-aided classification
The classification of images is done by a number of software packages (ELAS, LAS, ERDAS, etc.) An
excellent discussion of the techniques used appear in Lillisand and Kiefer 1979; Moik 1980; Schowengerdt.
1983; Jensen 1986; Ryerson 1989.
F. Data Storage
Life span of the data
In biological systems the usefulness of the data may be fairly short, in the order of several years, depending
upon the rate of change in the area.
Longevity of the storage medium must be considered. Magnetic tape lasts only about 10 years before
degrading, optical storage may last up to 50 years. Paper maps, on the other hand lasts for hundreds of
years when properly stored.
Assure current and future data compatibility
The exchange of digital data require not only software and hardware compatibility, but the methods of
collection and data base structure must be well documented. Technology is rapidly changing and the use of
arcane, home-brew, or non-standard software/hardware should be discouraged. Given that there is often a
high cost associated with creating an inventory, all these become especially important.
G. Product Delivery
1) Output or products
a. Digital tabular spatial data make geographical information systems (GIS) coverage (raster or vector)
analyses and updating relatively easy.
b. Paper (hardcopy, maps)
2) One-time or ongoing
H. Maintenance
Determine if the inventory is to be a one-time or ongoing project. If digital data are involved, there will be a
need to update the information, distribute information (tapes, disks), and answer questions.
I. Documentation
Documentation of the entire process must be maintained and published with the data. An excellent example
of what can go wrong if poor documentation is shown in (ESRI 1989). Documentation should include the
QNQC plan and information about how the data were collected, scale, map projection, coordinate system,
etc.
Literature Cited
Congalton, R.G. 1991. A review of assessing the accuracy of classification of remotely sensed data. Remote
Sons. Environ. 37:35-46.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of
the United States. Office of Biological Services, U.S. Fish and Wildlife Service, Washington, D.C. FWS/
OBS-79/31, 103 pp.
ESRI. 1989. An analysis of the Puget Sound Environmental Atlas. Report prepared for the Puget Sound Water
Quality Authority. Environmental Systems Research Institute. Redlands, California.
Hunsaker, C., D. Carpenter, et al. 1990. Ecological indicators for regional monitoring. BulL EcoL Soc. Amer.
71(3):165-172.
Jensen, J.R. 1986. Introductory digital image processing. Englewood Cliffs, N.J., Prentice-Hall.

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37 - Seagrass Science and Policy
Lillisand, 1. M., and R.W. Kiefer 1979. Remote sensing and image interpretation. New York, John Wiley and
Sons.
Lunetta, R.S., R.G. Congalton, et al. 1991. Remote sensing and geographic information system data integra
tion: Error sources and research issues. Photogram. Eng. and Remote Sens. 57(6):677-687.
Moik, J.G. 1980. Digital processing of remotely sensed images. National Aeronautics and Space
Administration.
Orth, R.J. and K.A. Moore 1983. Submersed vascular plants: Techniques for analyzing their distribution and
abundance. Mar. Technol. Soc. J. 17(2):38-52.
Ryerson, A. 1989. Image interpretation concerns for the 1 990s and lessons from the past. PERS 55(1 O):1 427-
1430.
Schowengerdt, R.A. 1983. Techniques for image processing and classification in remote sensing. New York,
Academic Press.
Story, M., and R.G. Congalton 1986. Accuracy assessment: A user’s perspective. Photogram. Erig. Remote
Sons. 52(3):397-399.
Webber, H. H., T.E Mumford, and J. Eby. 1987. Remote sensing inventory of the seagrass meadow of the
Padilla Bay National Estuarine Research Reserve. Areal extent and estimation of biomass. Report to
NOAAIOCRM/MEMD by Western Wash. Univ., Huxley College of Environmental Studies. 70 pp.
Bellingham, WA. Padilla Bay National Estuarine Research Reserve Reprint Series No. 6, 1990.

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38 - Sea grass Science and Policy
6. Seagrass Management In Washington State
Kurt L. Fresh
Washington State Department of Fisheries
Research and Development
P0. Box 43149
Olympia, Washington 98504-3 149
In this paper I briefly describe seagrass (Zostera marina and Z japonica) management in
Washington State and suggest ways the current system could be improved. The Washington State
Department of Fisheries (WDF) began to manage seagrass habitats in the late 1970’s and early
1980’s. During this time WDF and other regulatory agencies began to specifically protect seagrass
habitats. The focus of early management efforts was protection of those Z marina populations that
are used by Pacific herring (Clupea harengus pallasi) as spawning substrate.
Since the early 1980’s, habitat managers have become increasingly protective of seagrasses,
primarily as a result of three factors. First, there has been a national trend toward greater environ-
mental protection. Second, research conducted in this region has demonstrated that seagrass is an
important habitat for fish and wildlife. Third, seagrasses have become increasingly threatened by
shoreline development. Although there have been changes in the abundance and distribution of
seagrass in some areas of the state, it is difficult to determine whether changes are the result of
shoreline development or other factors, such as long term environmental changes.
A number of shoreline activities can potentially affect seagrasses in Washington, including
water quality changes, dredging and filling, construction of bulkheads, and overwater structures such
as piers, docks and floats (Phillips 1984, Thom 1990). A list of projects and their actual and potential
impact to aerial extent of eelgrass appears in Table 1. Of these, marinas which typically involve
several different types of impacts (e.g., dredging and water quality changes), account for the greatest
losses of seagrass. The loss of seagrass resulting from some activities is unknown. For example,
numerous small piers and docks that shade seagrass, have been built in the state. The number of
these structures built is not presently known, but in some areas (e.g., the San Juan Islands) it is
clearly substantial.
Many, often conflicting, factors affect the management of marine resources. One factor of
particular importance is science. Science has provided information on seagrass biology and ecology,
restoration techniques, functions, and the effects of shoreline development. The increase in our
knowledge about seagrass habitats in the region has played a crucial role in the evolution of seagrass
management. Although much has been discovered about seagrasses in Washington, a great deal
more remains to be learned. Information gaps include 1) natural patch dynamics, 2) methods for
mitigating impacts to seagrass, 3) the dependence of seagrass functions upon other surrounding
habitats, and 4) additional functions of seagrasses.

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39 - Sea grass Science and Policy
Of these issues, probably the most
important to WDF is increasing our
understanding of how to mitigate impacts
of shoreline development on seagrass.
Resource agencies, at present, have
adopted an aggressive “no net loss”
policy for seagrass. Mitigation proposals
are evaluated based upon the risks to
resources and the likelihood of mitigation
success, and generally, permits are not
issued to a developer unless there is a
high probability that impacts can be
successfully mitigated. One reason for
this policy is that the history of seagrass
transplanting in the Pacific Northwest has
not been encouraging (Thom 1990).
Resource agencies have responded to
this situation by tightening mitigation
requirements. Currently, mitigation that
either appears to have a high chance of
failing or that might impact critical re-
sources, typically requires full, upf rant
NA No activity on the project as of June 1993. M = A mitigation P mitigation or a demonstration that the
has been accepted or is in progress. 0 = Ongoing. The project is still
active, mitigation will be successful. This can

extend the project timeline many years.
Before these resource agencies can be expected to relax their current approach, basic research to
improve transplant success in the Pacific Northwest is needed.
A second factor that influences seagrass management is the specific groups or entities that
are involved in particular seagrass issues. The groups involved depend on the specific issues associ-
ated with a project, such as location and whether public lands are involved. Each entity has specific
authorities that define the breadth of their role on a project. I believe that the most important organiza-
tions are WDF and the U.S. Army Corps of Engineers (COE), because these agencies have broad
authority allowing them a role in the greatest number of seagrass projects.
A third factor influencing seagrass management is policy or course of action. To my knowl-
edge, the only seagrass policies that exist in Washington are informal (i.e. not officially adopted or not
written). There are, however, a number of other policies that exist that are directly relevant to
Table 1.
Projects In WashIngton State where seagrass Is an Issue. Projects
selected were those that have been active since 1988. Active was
defined as a project where an Hydraulic Project Approval (HPA) or COE
permit was applied for or granted, an EIS was issued or is being
developed, a developer officially contacted WDF about a project, or
impacts to eelgrass are dealt with in a management plan. For some
projects, information was incomplete.
Project
Lummi Bay Marina
Figalgo Bay Marina
Ship Harbor Marina
Development Ventures
Elliott Bay Marina
Swinomish Marina
Pt. Townsend Marina
John Wayne Marina
Roche Harbor Marina
Port of Skagit Co.
Port of Bellingham
Cape Sante Marina
Islander (Lopez Is.)
Ivar Jones Marina
Grays Harbor Widen
Trident Seat oods
Youngsman
Union Wharf
West Point Expansion
Ocean Spray Pipeline
Clinton Ferry Dock
Esplande (Magnolia)
Manchester Fuel Dock
Single Family Piers 5+
Texaco Oil Spill
Spartina Mgmt.
Beach Graveling
Fishing (Comm, Rec)
Oyster Culture
Year Status
1982-90 NA
1979+ NA
1985+ 0
1990+ O,M
1985+ O,M
1988+ 0
1988+ NA
1979+ O,M
1991+ 0
1990+ O,M
1990+ NA
1990+ 0
1992+ 0
1993+ 0
1980+ 0
1988+ O,M
1978+ 0
1989-92 NA
1988+ O,M
1989 ?
1992 0
1993+ 0
1986+ 0
1990+ O,M
1990+ 0
1991+ 0
1989+ .0
? 0
1850 0
Amount
8.00
14.00
17.00
0.50
0,25
2.00
1.50
2.00
1.00
0.10
2.00
1.00
0.25
20.00
20.00
0.25
0.20
0.10
0.10
0.50
11.00
9
0.50
9
?
?
200.00?

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40 - Seagrass Science and Policy
seagrass management. For instance, WDF has regulations that prevent the destruction of eelgrass
used for herring spawning.
A procedure that most regulatory agencies follow in managing seagrass is called “sequenc-
ing.” Sequencing is a systematic way of working through a proposed project to ensure that impacts are
first avoided where possible, minimized if they cannot be avoided, and then compensated (i.e. miti-
gated). Only those impacts that are unavoidable should necessitate mitigation. A diagram depicting
how this process is generally applied in WDF is shown in Fig. 1.
There are a number of ways that I think seagrass management can be improved in the future.
First, science can help by filling some of the critical information needs mentioned earlier. The most
important, in my viewpoint, is a better understanding of how to restore and mitigate impacts to
seagrasses in this region.
Other needed improvements in seagrass management are non-scientific and may include
increased communication between agencies and user/client groups. This may help increase the
public’s confidence in seagrass management practices. Client/user groups often do not understand
why particular decisions are made on projects (e.g., why transplantation is permitted in one project,
but not in another). This case-by-case approach has made it difficult for the public to use the past to
predict how new projects will be managed. This, in turn, has generated some concern about whether
agencies are consistent in their management. I think that agencies are consistent in how they manage
seagrass projects, but differences in authority, the specifics of each project, and the desire to achieve
“no net loss” result in the appearance of inconsistency.
Another improvement is the development of policies that are specifically oriented towards
protection of seagrass. Included in this should be the development of a formal mitigation policy that
lays out mitigation ratios, timelines, monitoring procedures, and other important factors.
Finally, a system of monitoring the progress of specific seagrass projects is needed. This
would include a computerized system that would allow specific projects to be tracked and maps
depicting possible changes in seagrass distribution and abundance to be developed. We do not know
if management efforts are achieving the desired goal of “no net loss”. Until we know this, it will be
difficult to determine if other changes in management might be warranted.
Literature Cited
Phillips, A. C. 1984. The ecology of eelgrass meadows in the Pacific Northwest: a community profile. U.S. Fish
Wildi. Serv., FWS/OBS-84/24, 85 p.
Thom, R.M. 1990. A review of eelgrass (Zostera marina L.) transplanting projects in the Pacific Northwest. The
Northwest Env. J. 6:121-137.

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41 - Seagrass Science and Policy
No \ No
seagress an issue? Yes
Project APPiic }! 8 (P/A) is there a potential impact
on seagrass?
Can Impacts be avoided?
Reconfigure. Redesign, Yes
Alternatives
No
Can Impacts be Minimized?
Reconfigure, Redesign,
Alternatives
IN
Yes No
V
r — I Evaluate
Classify in one of four
Mitigation Plan — categories (See I) Risks to resources
[ __ notes below) Choice of success -
CATEGORY 1
- Project and mitigation can proceed simultaneously
- <0.25 acres of eelgrass impacted
- Critical resources are not involved
- Mitigation has high chance of succeeding
- Mitigate at a ratio of at least 1.5:1
CATEGORY 2
- Demonstration of success is needed or mitigation is needed upfront
- One of these conditions is met:
• >0.25 Acres of eelgrass impacted
• critical resources are potentially impacted
• chance of success of the mitigation is low
• contingencies are inadequate
- Mitigate at a ratio of at least 2:1
CATEGORY 3
- Project not allowed to proceed
- critical resources are involved
CATEGORY 4
- Significant scientific benefit possible
- Project and mitigation can proceed under certain circumstances.
Figure 1. UnoffIcial WOF seagrass management model. The system WDF generally uses to handle a
seagrass project.

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42 - Sea grass Science and Policy
7. Restoration Of Damaged Eelgrass Habitats
Ronald M. Thom
Battelle Marine Sciences Laboratory
1529 W. Sequim Bay Road
Sequim, Washington 98382
Eelgrass (Zostera marina L.) has undergone substantial declines in many areas of the world
(Bulthuis, ch. 4, and Short and Wyllie-Echeverria, in prep.). In the Pacific Northwest, changes over
time are difficult to assess because baseline data are lacking, but local declines in urbanized bays are
documented (Thom and Hallum 1990). Eelgrass habitats are also under continuous pressure from
shoreline development. I estimated in 1991 that 17 development projects, potentially impacting a total
of at least 3,061 ha in Washington State, were proposed. To mitigate the impacts to eelgrass, devel-
opment of new eelgrass meadows through transplantation is often proposed (Thom 1990). Although
transplantation can be successful on a small scale (i.e. 1 m 2 ), larger-scale efforts generally have poor
success (Thom 1990). Poor success has led to low confidence among resource agency personnel in
the ability to restore or mitigate eelgrass losses through transplantation. This low confidence has
resulted in the denial of development permits and general frustration among developers, agency
scientists and eelgrass researchers.
There are a number of lessons that have been learned from past efforts to transplant eel-
grass, and these can be used in conjunction with the growing field of ecosystem restoration for
enhancing the probability of successfully restoring damaged eelgrass meadows. I discuss below
some key considerations for restoring eelgrass meadows. The information was compiled through the
development of materials for a course on wetland restoration for the National Oceanic and Atmo-
spheric Administration.
Definition of Restoration
Restoration may be defined as returning a system to a former, normal or unimpaired state.
“Predisturbance” condition is a term commonly applied to this state. However, because disturbances
are an integral part of the natural processes in ecosystems, “predisturbance” is not a valid concept.
The natural state of an eelgrass meadow may range widely in terms of shoot density, biomass,
productivity, seasonality, reproductive condition, and a variety of other parameters. Perhaps the best
goal for restoration is to return a meadow to conditions occurring in a local meadow that receives or
has received very little human impact. The goal of any restoration efforts must be well thought-out in
the context of the ecosystem.

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43 - Sea grass Science and Policy
Criteria for Intervention
When should a system be restored? How can we determine what is required to restore the
meadow? Steps to answer these questions have come from a working group of scientists that devel-
oped a habitat restoration research plan for
Table I
the U.S. Environmental Protection Agency, Questions to pose in restoring an eelgrass meadow
Corvallis Environmental Laboratory, in 1991.
The steps are posed as questions in Table 1. 1. What needs to be done to restore Site X?
2. What is the time frame of restoration?
Siting and Design of Restoration Projects Biological/Ecological
Socio political (funding)
The site will make or break a
restoration project (Thom 1990) Eelgrass 3 What are the objectives of restoration?
Aesthetics
requires a relatively specific set of environ- Species Composition
mental conditions, and the meadow must be Ecological Integrity
Critical (urgent)
appropriately placed within the ecosystem Landscape
and must be of adequate size and shape to
4. Why is it the way it is now?
best provide habitat and food resources to 1 Disturbance History
animals, and to supply organic matter to the . ,
5. What will happen if no restoration action is taken?
detrital food web. Landscape ecology
presents a viable method for siting and 6. What actions must be taken before restoration can be initiated?
(cleanup, remediation)
designing eelgrass meadows (Table 2). The
major problem with the use of landscape 7 What criteria do we use for success
ecology principles for this purpose is that 8. Can we rely on initial restoration actions and early results to
many of the empirical relationships that could predict final outcome?
be used in planning are not well-quantified.
Examples include the relationship between patch size and number of animals species, and shoot
density vs. number of animal species.
I have found several aspects of landscape ecology useful in planning habitat restoration
projects. Most of these are taken from a close reading of Forman and Godron (1986). The main
aspects are shown in Table 2. A primary goal of most restoration projects should be to establish a
self-maintaining system that functions optimally within the context of the landscape. To do this, habitat
size, connectivity and resilience are important siting and design considerations.
Criteria for Successful Restoration
What are the criteria for success? How should success be measured? What level of success
is acceptable? Is functional equivalency a viable concept and how does it relate to success? Is it
appropriate to require monitoring for the entire period of time it may take a system to fully develop (i.e.
80 years)? The fact is that scientists and regulators are still struggling with these questions. We

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44 - Sea grass Science and Policy
Table 2
Aspects of landscape ecology that can be used in siting and designing eelgrass restora-
tion projects.
Patches
A patch is a nonlinear surface area differing in appearance from its surroundings.
A matrix is the surrounding area within which the patch occurs. A matrix is the most extensive and most con-
nected landscape element, and therefore plays a dominant role in the functioning of the landscape.
Aspects of Patches:
1. Size - from Island Biogeography
S=CAZ
S= Number of species
C= Constant varying amoung taxa and unit of measurement
A= Area
Z= Constant which falls between 0.20 and 0.35
S=f(+l-Iabitat diversity within the patch OR ÷ Disturbance of the patch + Area of the patch - Isolation of
the patch from sources of species ±_ matrix heterogeneity - boundary discreteness)
2. Shape
Primarily related to edge effect
A. Different species composition
B. Different productivity
C. Export-import Process
D. Access by Animals and Plants
Measured by interior-to-edge ratio
A. Edge and interior species - fish and crab behavior
B. Show figure of effects of patch shape
C. Small patches may act as edges
D. Edges function differently from interiors
3. Patch Number and Configuration
Single large patches often contain more species than several smaller patches, although more species
are found in several patches if the patches are widely scattered.
Corridors
A corridor is a narrow strip of land that differs from the matrix on either side.
1. Connectivity is a measure of how connected or spatially continuous a corridor is, which may be quantified
by the number of breaks per unit length of corridor. Connectivity is the primary measure of corridor
structure.
2. Corridors function as
A. Habitat for some species
B. Conduit for movement along corridors
C. Barrier or filter
0. Source of environmental and biotic effects on the surrounding matrix
Disturbance and Stability
1. Stability - Long term variability is respresented by a straight tine
2. Persistence - Time period during which a certain characteristic of a landscape continues to be present
3. Resistance - Abiltiy to withstand variation due to disturbance
4. Recovery or resilience - Ability to bounce back after disturbance
5. Landscape Dynamics - Patterns of change in matrix and organization of the landscape over time
depends on level of force affecting the landscape and at what scale
Fonnan and Godrnn 1986

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45 - Sea grass Science and Policy
cannot fully answer all of them at present due to lack of data, but that we can make a stab at some of
them.
It is useful to envision how an engineer might handle the question of success about a project.
If you were to ask an engineer if the bridge he or she designed was successful, the response would
be couched in terms of facts relating to how well the bridge performed the job it was designed to do. If
the bridge supported the traffic, was durable, low maintenance, and would predictably continue to
function well for the life of the project, the engineer would probably judge the project a success. If an
earthquake shook the region, and the bridge withstood the shock within limits of the design, then the
project would be successful.
Seagrass restoration or mitigation through transplantations can and probably should be
judged in similar terms. Did the project meet design criteria? Is the transplanted eelgrass bed
expected to continue to develop through the life expectancy of the project? Can it withstand distur-
bances for which it was designed? I believe that we have enough information on what constitutes a
functioning patch of eelgrass to judge whether the patch is functioning as hoped. The latter two
questions are, however, problematical from the standpoint of judging success. We do not have a
good track record for success of projects, and long-term studies are essentially non-existent. We
know that very large projects usually fail and that very small projects, if done carefully, usually persist.
We simply do not have an ability to predict the life expectancy of a project. Perhaps we could evalu-
ate life expectancy in light of natural meadows. For example, how often does a meadow receive a
disturbance that is so great that the meadow is totally destroyed? In Padilla Bay, winter freezes and
heavy wind events occur almost every year, and damage to the Padilla meadow can be significant.
The size of the meadow is an effective buffer from this disturbance and recovery occurs from recruit-
ment from intact portions of the meadow. Smaller meadows may not be so lucky. The lesson we can
learn here is that large meadows that are located under appropriate physical and chemical conditions
probably can survive frequent and severe disturbances. We need more information on transplanted
and natural small meadows in terms of their disturbance frequency and recovery rates and processes.
Perhaps we could design a transplantation project to be able to withstand the 10 year wind storm (or
some other periodic disturbance). At least we would have a target design criteria analogous to the
bridge engineer.
Challenges
The greatest challenges are to:
1. improve the success rate for eelgrass meadow restorations,
2. understand the requirements for eelgrass,
3. develop and test technologies for successful establishment of eelgrass,
4. increase the predictability of our actions in restoring eelgrass meadows, and
5. understand how meadows best fit physically and ecologically within the context of the landscape.

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46 - Sea grass Science and Policy
Literature Cited
Fonseca, M.S. 1992. Restoring seagrass systems in the United States, Pp. 79-110 in G.W.
Thayer (ed). Restoring the nation’s marine environment. A Maryland Sea Grant Book, College Park.
Forman, R.T.T., and M. Godron. 1986. Landscape ecology. John Wiley & Sons, Inc.
Shreffler, D.K. and R.M. Thom. 1993. Restoration of urban estuaries: New approaches for site location and de-
sign. Prepared for Washington State Department of Natural Resources. Battelle, Pacific Northwest Labora-
tories, Richland, WA, 107 pp.
Simenstad, C.A., and R.M. Thom. 1992. Restoring wetland habitats in urbanized Pacific Northwest estuaries,
Pp. 423-472 in G.W. Thayer (ed). Restoring the nation’s marine environment. A Maryland Sea
Grant Book, College Park.
Short, F., and S. Wyllie-Echeverria. Disturbance in seagrass: A review (in prep).
Thom, R.M. 1990. A review of eelgrass (Zostera marina L.) transplanting projects in the Pacific Northwest. The
Northwest Environ. J. 6:121-137.
Thom, R.M., and L. Hallum. 1990. Long-term changes in the aerial extent of tidal marshes, eelgrass meadows
and kelp forests of Puget Sound. Final report to U.S. Environmental Protection Agency. Fisheries Research
Institute, University of Washington, Seattle. EPA 910/9-91-005.

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FRAMEWORKS FOR ANALYSIS OF THE ISSUES
Environmental policy and scientific research should be mutually supportive (Lubchenco et al.
1991, Lee 1993). In this section we present two parallel and interdependent approaches (see Fig. 1)
to defining priorities for policy development and ecological research regarding seagrasses in the
Pacific Northwest region. Hershman and Lind develop a systematic analysis of legal and institutional
arrangements that govern resource uses and the impacts of human activities. They evaluate existing
seagrass policy to identify gaps and set priorities for new policy development. Similarly, Olson and
Straub present an approach to quantifying trends or biases in existing research on eelgrass, in order
to target previously under-represented or emerging research topics and approaches. Ultimately, we
plan to bring the two analyses together to jointly evaluate the need for policy changes and scientific
research. Specifically, the management needs identified by Hershman and Lind will become criteria
for priority-setting for ecological research, and emerging trends in ecological research identified by
Olson and Straub will suggest new areas for policy development.
Analysis of Analysis of
Legal and Scientific
Institutional Knowledge
Context Base
__ I
Pñorities for
Priorities for
Management
Ecological
and Policy
Research
Development
Figure 1. Frameworks for analysIs of management and scientific issues.

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48 - Sea grass Science and Policy
8. Evaluating and Developing Seagrass Policy
in the Pacific Northwest
Marc J. Hershman
and
Kent A. Lind
School of Marine Affairs, HF-05
University of Washington
Seattle, Washington 98195
The intent of this section is to present a framework for the analysis of the legal and institutional
context for seagrass science and policy development. Such an analysis helps establish priorities for
management and for ecological research (Fig. 1 on previous page). In turn, the scientific knowledge
base informs the legal and institutional context. Our discussion proceeds in two steps. First, we
provide a brief overview of seagrass protection and management policies in the Pacific Northwest,
(Fig. 2) illustrating the scope of current policies and suggesting criteria for evaluating their effective-
ness. Second, we suggest several steps decision-makers should take in designing, implementing and
evaluating new seagrass policies. These steps are outlined in the form of five questions (Fig. 3). Our
basiô premise is that government capacity to manage natural resources and the environment is
stretched to its limit and choices must be made. Even worthwhile new seagrass policy initiatives must
be evaluated in comparison with other pressing policy needs, and in terms of the personal and budget-
ary resources available to implement the policies.
Evaluating Current Seagrass Policies in the Pacific Northwest
In Figure 2 we pose the question “Are seagrasses adequately managed under current poli-
cies?” and outline the scope of agencies and polices involved in the protection and management of
seagrasses in the Northwest. Most striking, perhaps, is the diffusion of seagrass management
activities among a wide variety of agencies at every level of government. This is due, in part, to the
fact that most of the policies listed in Figure 2 are aimed at managing various types of human activity
rather than managing a particular resource such as seagrass. Among the different types of policies
we have identified are:
Project Review. This type of policy is conducted by a variety of agencies at all levels of govern-
ment. Fresh (ch. 6) suggests that in Washington, the State Department of Fisheries (WDF) has
taken the lead in reviewing development projects for possible threats to seagrass resources. We
have found that some counties (e.g., San Juan and Whatcom Counties) are also adopting
seagrass protection in their shoreline master programs.

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Review of Policies
Project Review
Agencies : COE, EPA, WDOF
NMFS, USFWS, local gvts
Policies : (NEPA, Sec. 404,
Sec. 10, HPA, CZM, GMA,
etc.)
Water Quality
Agencies : EPA, Ecology,
PSWQA, local govt’s
Policies : Nonpoint source,
NPDES, CWA, Stomiwater
programs, monitohng
Public Land Mgt
Agencies : DNR, DOD, Tribes
Policies : Protection, cultivation,
inventory, leasing, etc.
RestorationlHabitat
—t
Agencies : EPA, NOAA,
USFWS, DNR, Ecology
Policies : NRDA, CERCLA,
Mitigation
Damage Reduclion
Oil spills, infestation,
disease, etc.
Inventory and Mapping
NWI, DNR, NOAA, GIS
Criteria for
Evaluating Policies
• Is the relative
importance of the resource
properly understood?
(Ecological, economic,
political, cultural)
• Is the status of the
resource property
understood? (adequate
information on abundance,
trends/shrinking or
growing, lost functions,
potential threats?)
• Does the agency/policy
have appropriate
geographic scope?
• Does the agency/policy
regulate appropriate
activities?
• Adequate funding?
• Conflict or cooperation
with other agencies or
policies
• Adequate powers?
• Do policies compare with
trends from other
jurisdictions?
Basic Premise
Many policies are needed
but govt capacity is
stretched to its limit.
Choices must be made.
Question
Are seagrasses
adequately protected
and managed under
the current policies?
Decision
NO:
Current Policies
do not adequately
protect seagrass
resources.
YES:
Current Policies
are adequate
Policy Options
• Change/upgrade
existing policy
• Initiate new policy
• Combination of above
• No change
Figure 2. EvaluatIng current seagrass policies in the Pacific Northwest

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50 - Seagrass Science and Policy
Water Quality. In the Pacific Northwest, threats to seagrass from water quality degradation are
not as well documented as for Atlantic waterbodies such as the Chesapeake Bay (Bulthuis, ch. 4).
Nevertheless, National Pollution Discharge Elimination System (NPDES), nonpoint source and
stormwater management programs may directly affect and improve the health of seagrass re-
sources.
Public Land Management. These are policies of the state, federal and tribal agencies that own
the submerged lands that support most seagrass beds. Policies may include such activities as
protection, cultivation and leasing.
Restoration/Habitat Development. In recent years, a variety of agencies have implemented
aquatic restoration and habitat development projects. Restoration of seagrass beds may be
included in some of these projects. Often restoration is required as part of mitigation requirements
attached to particular development projects.
Damage Reduction. Oil spill cleanup regulations are an example of this type of policy. As the
technology of seagrass transplanting and restoration advances, seagrass restoration may play a
larger role in the cleanup of spills.
Inventory and Mapping. According to Mumford (ch. 5) Washington State Department of Natural
Resources (DNR) has completed seagrass inventories for most of Washington’s intertidal zone.
However, most seagrass beds in the subtidal zone have not been inventoried. Even mapping
programs such as those conducted by the National Oceanic and Atmospheric Administration
(NOAA) and the National Wetlands Inventory do not routinely include seagrass resources.
To evaluate these current policies, adequate criteria must be chosen. Various criteria that may
prove useful are listed in Figure 2. For example, geographic scope may be an appropriate evaluation
criteria. Many current agencies and policies may lack the necessary geographic scope to effectively
protect seagrasses. Shoreline management programs have jurisdiction over shallow water areas.
Typically, however, shoreline programs neglect intertidal and subtidal resources and put all their
attention on land use activities in the first 200 feet of shorelands. By contrast, water-oriented agencies
(e.g., Corps of Engineers (COE) and DNA) may not extend upland enough to cover seagrass species
that inhabit shallower intertidal zones, or regulate upland activity that can impact subtidal zones.
A decision is needed after asking the basic question: Are seagrasses adequately protected
and managed under current policies? The lack of basic information on the status of the resource,
especially in the subtidal zone, may suggest further study. In general, federal and state jurisdiction
exists over seagrasses under laws such as §404 of the Clean Water Act and the State Hydraulics Act.

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51 - Seagrass Science and Policy
However, we found no specific policies for managing seagrasses in the Northwest, although one is
under consideration by WDF (Fresh, ch. 6). Seagrass issues emerge primarily at the project review
level. Other regions such as the Chesapeake Bay and Southern California have more extensively
developed seagrass policies. For example, the Chesapeake Bay Program proposes establishing
minimum light requirements for seagrasses and now uses the health of seagrass beds as a primary
water quality indicator in the Bay (Dennison et al. 1993). In Southern California, the National
Marine Fisheries Service has established policies to govern seagrass transplanting for compensatory
mitigation (Robert Hoffman, NMFS, Southwest Region, pers. comm.).
Designing, Implementing and Evaluating New Seagrass Policies
Figure 3 illustrates the type of policy process that is warranted if it is decided that current
policies are inadequate and policies specific to seagrass resources should be created or amplified.
We have diagrammed the design, implementation, and evaluation of new policies as a five-step
process using five basic questions that should be asked during the process:
1. What are the alternative policies that could solve seagrass problems?
2. Which alternative is preferred and should it have priority over other policy needs?
3. How is a seagrass policy designed?
4. How is a seagrass policy implemented?
5. Is the seagrass policy working?
We use two examples of possible seagrass policies to illustrate the policy process outlined in
Figure 3. One possible policy alternative might be to stress transplanting to mitigate for damages to
seagrass beds. However, WDF now believes that Pacific herring may not be able to utilize trans-
planted seagrass beds for spawning nurseries. In addition, the cost of transplanting may prohibit any
large scale projects. The result of a thorough policy analysis of seagrass transplanting may, in fact,
produce restrictions on transplanting that discourage its use.
A second policy alternative may be for an agency with a broad stewardship mandate such as
the DNR to take the lead in seagrass management. DNR may have advantages over other state and
federal agencies, because it owns much of the submerged lands with seagrass beds. In addition,
DNA is not necessarily project-oriented in its approach to management. By contrast, WDF and COE
only act in response to development projects, where there is a threat to existing resources. As stew-
ard of the state’s submerged lands, DNR has a broader mandate to intervene in response to natural or
man-made threats to the resource that may not be project or development-oriented. Typical policy
examples might be:
• Restrictions on boating where propellers may disturb critical seagrass beds.
• Programs to control invasive species that threaten native seagrass beds (e.g.
Spartina infestations in Willapa Bay).

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Question #1
What are
aftemative
policies that could
solve seagrass
problem(s)?
Sources of
Information
• Trends
from other
jurisdictions e.g.,
types of
regulation (light
requirements)
• New
technologies
• Inventory and
research needs
Question #2
Which alt. is
preferred and
should it have
pnonty over
other policy
needs?
Criteria for
Analysis
• Benefits of each
altemative
• Costs to develop
and implement?
• Comparison with
other policy needs
(e.g., endangered
species, scenic
resources)
Question #3
How is a seagrass
policy designed?
Categories
• Information
base needed
• Powers!
Authority
• Organizational
arrangements
. Costs
• Decision
Question #4
How is a seagrass
policy implemented?
Categories
• Personnel and
budget
• Detailed regs
or guidelines
• Information
generation and
dissemination
• Decision
procedures
Question #5
Is a seagrass policy
working?
Criteria for
Analysis
• Outcome
evaluation
•Process
evaluation
Figure 3. Designing, implementing and evaluating new seagrass policies.

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53 - Sea grass Science and Policy
• Nonpoint source pollution programs where water quality problems threaten seagrass
beds (e.g. Chesapeake Bay).
• Restoration of degraded seagrass beds by transplant or protection policies.
• Policies dealing with cumulative impacts that might degrade seagrass resources. Cowper
(1979) reviewed state and federal laws touching upon the management of seagrass
beds and concluded that the establishment of management plans for seagrass would
be consistent with most states coastal zone management programs. Such plans
could be adopted by regulation in most states without resorting to the cumbersome
legislative process.
Conclusion
This section has presented a few brief thoughts on possible seagrass policy in the Pacific
Northwest. It does not represent extensive research into current policies or possible initiatives. Figure
1 illustrates the current scope of management activities that relate to seagrasses. A wide variety of
policies already exists, but most are responses to human threats to the environment, rather than
specific seagrass management programs. For this reason we conclude that there is no need for a
major overhaul of the regulatory system just for seagrasses. However, it would be valuable for the
aquatic lands program in DNR to be upgraded to facilitate stewardship of submerged lands. Other
chapters in this volume have identified areas where increased research or enhancement of seagrass
programs may be justified. Mumford (ch. 5) has pointed out the gaps in current resource inventories.
Fresh (seminar presentation) has described our lack of knowledge about the relationship between
spawning Pacific herring and particular seagrass beds. Seagrass transplanting (Thom, ch. 7) is
another area that may warrant further research.
Literature Cited
Cowper, S.C. 1979. A review of existing laws touching upon management of seagrass beds. Pp. 252-268 in
C.P. McRoy and S. Williams-Cowper. Seagrasses of the United States: An ecological review in relation to
human activities. U.S. Fish and Wildlife Service, Biological Services Program. FWS/OBS-77/80. 283pp.
Dennison, W.C., R.J. Orth, K. A. Moore, J. C. Stevenson, V. Carter, S. Kollar, P.W. Bergstrom, and R.A. Batiuk.
1993. Assessing water quality with submerged aquatic vegetation: habitat requirements as barometers of
Chesapeake Bay health. BioScience 43:86—94

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54 - Seagrass Science and Policy
9. Ecological Models In Research On Eelgrass:
An Approach To Setting Research Priorities
Annette M. Olson
and
A/ton Straub
School of Marine Affairs, HF-05
University of Washington
Seattle, Washington 98195
The goal of this paper is to describe a new, quantitative method for setting ecological research
priorities for Zostera marina (eelgrass) dominated systems. As a supplement to the use of “expert
opinion” to develop a research agenda, our approach attempts to systematically identify trends or
biases in existing research, and to target under-represented research topics and approaches. Our
ultimate goal is to identify areas of overlap between science-driven and policy-driven research ques-
tions. This will be a two-step process: The first step, outlined in this paper, is a quantitative and
qualitative analysis of the scientific knowledge base. Here, we propose to create a “map” of current
scientific information on the ecology of eelgrass-dominated ecosystems, with a set of “overlays,”
indicating the quantity and quality of information on different aspects of the system. We will also use
existing ecological theory to predict which types of human activities have a high potential to result in
unanticipated outcomes, given what is currently known about the eelgrass system. Second, in a
subsequent paper, we will use the management priorities identified by Hershman and Lind (ch. 8) as a
policy-oriented “overlay” on our set of scientifically defined research priorities to target research topics
that both address fundamental ecological questions and contribute to the management of eelgrass
dominated ecosystems in the Pacific Northwest.
Ecological Models In Environmental Decision-Making
Ecological knowledge forms one of the scientific bases for predicting and assessing environ-
mental impacts and for recommending regulatory management or restoration alternatives (Lubchenco
et al. 1991). The same ecological models (Boxes 1 & 2) that are used to explain environmental
impacts also form the causal basis for taking particular corrective actions. More specifically, ecological
models define environmental problems in terms of particular sets of causal variables; they determine
the appropriate methodology for assessing impacts and monitoring environmental change, specifying
data needed and criteria for assessment; and they constrain the set of corrective actions to those
addressing variables in the model. Thus, the success of environmental planning and management
activities depends, in part, on the adequacy of the implicit or explicit models that depict how human
activities might cause environmental outcomes. Additionally, the ecological models invoked in the
policy arena define the agenda for further research. Because both environmental decision-making

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55 - Sea grass Science and Policy
and the discovery of new ecological knowledge will thus depend on the particular model adopted
(Botkin 1990, Pimm 1991), we are interested in identifying the prevailing conceptual models (Box 1) in
ecological research on eelgrass.
Ecological Models In Research On Eelgrass—Goals And Approach
In order to determine what models are being tested in current research on eelgrass, we have
(1) conducted a comprehensive search of studies published in both the peer-reviewed and “gray”
literature, (2) developed the ZOSTERA database (Appendix, page 57) for cataloging and classifying
studies, and (3) begun to classify studies and enter them into the database.
We will analyze the ZOSTERA database to identify ecological research priorities, using three
i, . primary criteria—research effort, re-
Box 1 search quality, and ecological complexity
What is an ecological model?
We will quantitatively assess research
An ecological model can be thought of as a hypothesis about how one effort,” the absolute number of studies
ecological element or process affects another. For the purposes of this
study, we define a model as any pair of variables (dependent and conducted, by class of model, or ecologi-
independent) linked by a putative causal relationship A lab or field
study of the relationship between variables X and Y is a test of a model cal paradigm (see Box 1) and by specific
about the causal relationship between X andY. Thus, models are
hypotheses about the relationship between models, or pairs of variables (see Box 1),
• resources and populations to detect trends and gaps in the types of
• competing populations
• consumers and their prey . . models tested. One product of these
• abiotic factors and any component of the ecosystem analyses will be a “map” of ecosystem
ASET OF MODELS LINKING EELGRASS, . elements (e.g., eelgrass; associated
EPIPHYTES, AND HERBIVORES
epiphytes, herbivores, carnivores; and
Macroherbivores Mesoherbivores physical factors affecting eelgrass beds)
+ 1 + .—Stress On this map, research effort (i e, num-
- bers of studies) will be indicated by the
Eelgrass _ _1I__’ Epiphytes ‘— Disturbance
- / width of the lines linking ecosystem
+ “\ . / + elements. Research topics which are
Nutrients currently under-studied will thus be
I highlighted, allowing decision-makers to
Note that in most cases, either variable in the pair may be the direct research funds toward promising
dependent or independent variable, depending on the design and
interpretation of the study. new research questions. The second type
We have identified six main classes of models or ecological paradigms, of analysis will address “research quality,”
in which ecological processes are thought to be controlled by (1) indicative of the relative reliability of the
availability of resources such as nutrients, light or prey items (Bottom-
up models), (2) predation (including herbivory) and/or predator- available results. Indicators of research
avoidance (Top-down models), (3) physical disturbance, such as -
sedimentation or erosion, (Disturbance models), (4) physiological quality include
stress, such as desiccation or toxic contamination (Stress models), (5)
the timing of events, such as seasonal or tidal variation (Temporal • Approach (tradeoffs exist in
models), or (6) the spatial pattern of ecological elements or processes, .
such as patch size or distance between patches (Spatial models), — precision and generalizability

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56 - Seagrass Science and Policy
between experimental vs. lab approaches)
• Replication (studies with higher replication are more sensitive to subtle changes; some
studies are “pseudoreplicated” due to deficiencies in design, invalidating the statisti-
cal analysis of the results)
• Duration, frequency of sampling (studies of longer duration and more frequent sampling
are more likely to “pick up” environmental variability)
• Geographic scope (broader geographic scope permits more gerieralizability of results)
• Complexity of design (if external factors are controlled or manipulated, the conditions
under which the results will hold are more easily predicted)
• Congruence among results (if results of several studies are congruent, the conclusions
of those studies are more robust than if conflicting results have been observed)
Using these analyses, we will produce a set of “overlays” that relate research quality to research effort,
highlighting areas of the scientific knowledge base that would be enhanced by improvements in study
design, scope, duration, etc.
Third, we will use existing ecological theory to highlight complex ecological relationships, such as
indirect effects, that result in a high potential for unanticipated outcomes. Indirect effects are ecologi-
cal interactions—mediated by consumers, competitors, disease, or other factors—that can change
how one ecosystem component responds to natural or anthropogenic environmental change (e.g.,
Louda 1988, Carpenter et al. 1993, Zedler 1993). For example, if toxic contaminants eliminate the
herbivores that control epiphytes, eelgrass may decline due to increased epiphyte loads, even if the
contamination is within its tolerance range. Where such indirect effects are important, the tolerance of
eelgrass to contamination would not be a good predictor of its distribution in contaminated habitats.
Thus, priority should be given to research on ecological interactions that are likely to improve predic-
tions about the response of the eelgrass-dominated ecosystem to external influences (Kingsolver et al.
1993).
Preliminary Results
Three preliminary results are suggested by an informal review of the data: First, there appears to
be a bias toward bottom-up approaches, with less emphasis on the potential top-down effects of
consumers (i.e., herbivores and carnivores) in structuring the eelgrass community. However, this
trend may be changing, as evidenced by a recent study (Williams and Ruckelshaus 1993), in which
both top-down and bottom-up effects were investigated. Because top-town processes have been
shown to have very strong effects in structuring other aquatic ecosystems (Power 1990, Carpenter et
al. 1985), priority should be given to determining their significance in eelgrass-dominated systems.
Second, field experiments have rarely been conducted in eelgrass beds to test hypotheses
generated by descriptive field studies and laboratory experiments. Although field experiments are

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57 - Sea grass Science and Policy
logistically difficult, they have been critical in
determining both the types and relative
importance of ecological interactions in other __________________________
soft-sediment systems (Woodin 1978,
Jumars 1993), and should be encouraged in
research on eelgrass systems.
Third, much of the recent research
seems to have been driven by an interest in
developing transplantation as a policy option
for mitigating habitat destruction (Disturbance
models, Table 2; Bulthuis, ch. 4). Studies
that address off-site influences on habitat
quality (e.g., non-point source nutrient or
toxic pollution) (Stress models, Box 2), are
relatively rare. This case illustrates how the
particular ecological model adopted to
explain eelgrass decline has significance
both for management policy and future
ecological research (Box 2). Research
priority should be given to understanding the
role of habitat quality in the persistence of
natural eelgrass beds and in the success of
mitigation projects.
Conclusions
Our goal in developing the ZOSTERA database is to define a scientific research agenda that both
advances fundamental ecological knowledge and simultaneously contributes to solving environmental
problems. Analysis of the ZOSTERA database will identify new research directions, based on previ-
ous research effort, research quality, and policy-relevant ecological complexity. Central to this effort
will be the production of an ‘overlay” of management information needs generated by policy analysis
(Hershman and Lind, ch. 8), permitting decision-makers to identify research programs that both
answer important ecological questions and address the information needs of environmental managers.
Literature Cited
Botkin, D.B. 1990. Discordant harmonies: A new ecology for the twenty-first century. Oxford University Press,
NY, U.S.A.
Carpenter, S.R., J.F. Kitchell, and J.R. Hodgson. 1985. Cascading trophic interactions and lake productivity.
BioScience 35:634-639.
Box 2
Alternative models for eelgrass decline
Habitat Destruction (Disturbance) Models
Problem Definition:
Hab at destruction , due to
disturbance
Assessment/Monitoring:
Corrective Action:
Inventory habitat, status of
populations
Research Priorities:
Mitigation (replacement or
enhancement)
Identify biological and physical
factors affecting transplant
success
Light-Limitation (Stress) Model
Problem Definition:
Reduction in habitat quality
due to turbidity
Corrective Action
Monitor light attenuation,
population “health”
Research Priorities:
Manage water clarity
Identify factors affecting light
levels, study eflects of light on
performance/distribution of
eelgrass.

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58 - Sea grass Science and Policy
Carpenter, SR., T.M. Frost, J.F. Kitchell, and T.K. Kratz. 1993. Species dynamics and global environmental
change: a perspective on ecosystem experiments. Pp. 267-279 in P.M. Kareiva, J.G. Kingsolver, and R.B.
Huey (eds.), Biotic interactions and global change. Sinauer Associates Inc., Sunderland, MA, USA.
Jumars, P.A. 1993. Concepts in biological oceanography: an interdisciplinary primer. Oxford University Press,
NY, USA.
Kingsolver, J.G., R.B., Huey, and P.M. Kareiva. 1993. An agenda for population and community research on
global change. Pp. 480-486 in P.M. Kareiva, J.G. Kingsolver, and RB. Huey (eds.), Biotic interactions and
global change. Sinauer Associates Inc., Sunderland, MA, USA.
Lee, K.N. 1993. Compass and gyroscope: integrating science and politics for the environment. Island Press,
Washington, D.C., USA.
Louda, S.M. 1988. Insect pests and plant stress as considerations for revegetation of disturbed ecosystems. Pp.
51-67 in J. Cairns, Jr. (ed.), Rehabilitation of damaged ecosystems. CRC Press, Boca Raton, FL, USA.
Lubchenco, J., A.M. Olson, L.B. Brubaker and others. 1991. The sustainable biosphere initiative: an ecological
research agenda. Ecology 72:371-412.
Pimm, S.L. 1991. The balance of nature?: ecological issues in the conservation of species and communities.
The University of Chicago Press, Chicago, II, USA.
Power, M.E. 1990. Effects of fish in river foodwebs. Science 250:811-814.
Willimas, S.L., and M.H. Ruckelshaus. 1993. Effects of nitrogen availability and herbivory on the interaction
between ee lgrass (Zostera marina L) and epiphytes. Ecology 74:904-918.
Woodin, S.A. 1978. Refuges, disturbance, and community structure: a marine soft-bottom example. Ecology
59:274-284.
Zedler, J.B. 1993. Canopy architecture of natural and planted cordgrass marshes: selecting habitat evaluation
criteria. Ecol. App/ic. 3:123-138.

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59 - Sea grass Science and Policy
Appendix: ZOSTERA Database
The ZOSTERA database is a relational database, using ABASE software, that consists of four linked
tables or files:
1. The PUBLiCATION table contains bibliographic information, identifying the source of data. This is
the master file that links all the other files in the database.
2. The FUNDING table contains records describing the sources of support for the study, based
on the sponsoring agency(ies) or citations in the “Acknowledgments” of the publication. More than
one FUNDING record may be associated with a given PUBLICATION record.
3. Each record in the STUDY table is based on a set of sampling or experimental units. That is, the
observations taken on a set of plots in the field or plants taken into the lab would make up a ‘study.’
Because several studies may be reported in a single publication, more than one STUDY record may
be associated with a given PUBLICATION record. Information about a given study would include
• Location
• Approach: Experimental vs. observational
• Context: Lab, field, mesocosm, microcosm
• “Quality’: Design, replication, duration and frequency of sampling
4. The MODEL table records the specific models that were tested in a given study. Thus,
each MODEL record documents the relationship between a single pair of independent and depen-
dent variables. Because several models may be tested in a particular study, more than one MODEL
record may be associated with a given STUDY record. For example, investigators may have
measured how several plant characteristics (such as leaf length and width, nutrient content, and
growth rate) respond to various fertilization treatments. Information recorded about a given model
includes
• Class of model: one of six classes (see Box 1)
• Dependent and independent variables
• Relationship between dependent and independent variables (e.g. statistical significance,
sign of the relationship, whether other variables were simultaneously manipulated or
measured).

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CONCLUDING REMARKS
During the seminar and subsequent meetings of the Interdisciplinary Seagrass Working
Group, several key issues emerged. These issues have direct bearing on future coastal zone man-
agement in the Pacific Northwest and include
• The potential for non-point source impacts on the quantity and quality of habitat
suitable for persistence of seagrasses. Light limitation of seagrass distribution has been
documented for numerous other seagrass systems and is currently under investigation in
Puget Sound. However, the need for new policy directed at managing the effects of dredging,
agriculture, forestry, urbanization or other human activities on seagrass resources cannot be
assessed without further scientific studies that document the nature and extent of impacts
from these activities to seagrass habitat quality.
• The need for resource inventories documenting seagrass distributions and character-
izing populations. Avoidance and minimization of impacts depends on an adequate under
standing of the extent and condition of native seagrass populations. Basin-scale planning
and restoration-siting also depend on accurate information about historic and present
seagrass distribution. In our region, this information is almost entirely lacking, particularly for
subtidal populations. Defining the scale and resolution of a comprehensive baseline inven-
tory is an urgent policy and research priority. The distribution and spread of exotic
seagrasses, along with possible possible impacts to native ecosystems, also requires further
study.
• The need for restoration of seagrass systems destroyed by coastal zone development.
Despite our lack of knowledge about historical distributions, unavoidable impacts on extant
seagrass populations occur and require mitigation. In our region, seagrass transplant
technology has not been successful at the spatial scales necessary to comply with a “no net
toss” mitigation goal. Research on habitat suitability, transplant techniques and source
population characteristics is needed to improve success of mitigation efforts. Policy directed
toward monitoring and evaluation of mitigation attempts is also needed to enhance institu-
tional learning.
• Enhanced coordination of regulatory and management activIties. Attention to
seagrasses by regulators and managers occurs mostly through the review of development

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projects. In these cases, seagrass impacts are one of many impacts reviewed using general
criteria. There is no specific seagrass policy in the Pacific Northwest although Washington
Department of Fisheries is developing one (Fresh, ch. 6). Missing also are specific seagrass
management programs that can monitor and protect the resources from threats not associ-
ated with development projects (e.g. boating, invasive species and cumulative impacts).
• Ethnobotanical information and its relevance to policy decisions. Ethnobotanical
investigations briefly described in Wyllie-Echeverria and Phillips (ch. 1) raise several
questions: 1) Is this type of information useful for regional seagrass management or is it
simply of academic interest? 2) Are seagrasses, in addition to being an important component
in coastal food webs, also an important cultural resource? and should plans to designate
“Marine Protected Areas” incorporate this type of information? and 3) Are there medical and
nutritional properties to the plants that warrant further examination? These questions might
provide the basis for future analysis.
• Comparative studies with seagrass systems and policy agendas and activities in other
regions of the U.S. During the formulation of the seminar we realized the importance of
evaluating scientific and institutional models derived from Atlantic and Gulf regions regarding
their appropriateness for the Pacific Northwest. Before we can determine whether Pacific
Northwest seagrass systems and management histories are uniquely different and warrant
special attention these comparisons are necessary.
• The need for linking management research with basic ecological research. We propose
that this research could take the form of an “experiment station”. This approach would allow
us to simulate cultural activities that create or destroy seagrass habitats. Much of the current
scientific research is driven by the regulatory environment. This environment builds a case for
preservation and establishes strict standards for transplants, based on “no net loss” crite ia. A
research environment is needed that allows for more bold work not burdened by this bias to-
ward regulatory approaches.
Additionally, we propose that this type of analysis should extend to other submerged land habitats. In
the Pacific Northwest, “submerged lands”, as compared to “shorelands”, have received little attention
from both research scientists and coastal zone managers. Seagrass management should be folded
into this larger scheme of management. Comparative research on management forms and operations
in other states, regarding “submerged land management”, and the place of seagrasses within this
management, needs to be done before specific recommendations regarding Pacific Northwest
seagrass management can be made.

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63 - Sea grass Science and Policy
In summary, we realize that, while this is not the beginning of discussions involving seagrass
science and policy, it is also not the end. Our immediate goal is to design the possible forms the next
iteration should take. Toward that end, we introduced two corresponding yet interdependent ap-
proaches to defining priorities for policy development and ecological research regarding seagrasses in
the Pacific Northwest region (Hershman and Lind ch. 8; Olson and Straub, ch. 9). Ultimately, this
discussion will, and should, involve a wider audience. This document provides a ‘white paper” around
which future discussion can be focused.

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