DOC
EPA
United States
Department of
Commerce
National Oceanic and Atmospheric
Administration
Seattle WA 98115
United States
Environmental Protection
Agency
Office of Environmental Engineering
and Technology
Washington DC 20460
EPA-600/7-80-032
February 1980
             Research and Development
             Plankton of the
             Strait of
             Juan de Fuca
             1976-1977

             Interagency
             Energy/Environment
             R&D  Program
             Report

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology.  Elimination  of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

      1.   Environmental  Health Effects Research
      2.   Environmental  Protection Technology
      3.   Ecological Research
      4.   Environmental  Monitoring
      5.   Socioeconomic Environmental Studies
      6.   Scientific and Technical Assessment Reports (STAR)
      7.   Interagency  Energy-Environment Research and Development
      8.   "Special" Reports
      9.   Miscellaneous Reports

This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on  the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed  for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                  Replacement for  Inside  Cover
                  RESEARCH REPORTING SERIES

 Research reports of the Office of Research and Development, U.S. Environmental
 Protection Agency, have been grouped into nine series. These nine broad cate-
 gories were established to facilitate further development and application of en-
 vironmental technology.  Elimination of traditional  grouping was consciously
 planned to foster technology transfer and a maximum interface in  related fields.
 The nine series are:

       1.   Environmental Health Effects Research
       2.   Environmental Protection Technology
       3.   Ecological Research
       4.   Environmental Monitoring
       5.  Socioeconomic Environmental Studies
       6.  Scientific and Technical Assessment Reports (STAR)
       7.  Interagency Energy-Environment Research and Development
       8.  "Special" Reports
       9.  Miscellaneous Reports

 This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
 RESEARCH AND DEVELOPMENT series. Reports in this series result from the
 effort funded under the 17-agency Federal Energy/Environment  Research and
 Development Program. These studies relate to EPA's mission to protect the public
 health and welfare from adverse effects of pollutants associated with energy sys-
 tems. The goal of the Program is  to assure the rapid development of domestic
 energy supplies in an environmentally-compatible manner by providing the nec-
 essary environmental data and control technology. Investigations include analy-
 ses of the transport of energy-related pollutants and their health and ecological
 effects; assessments of, and development of, control  technologies for energy
 systems; and integrated assessments of a wide range of energy-related environ-
 mental issues.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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      PLANKTON OF THE STRAIT OF JUAN DE FUCA, 1976 - 1977

                               by

                     Alexander J. Chester
                       David M. Damkaer
                        Douglas B. Dey
                        Gayle A. Heron
                       Jerry D. Larrance
            Pacific Marine Environmental  Laboratory
              Environmental  Research Laboratories
        National  Oceanic and Atmospheric  Administration
                   7600 Sand Point Way N.E.
                  Seattle, Washington  98115
Prepared for the MESA (Marine Ecosystems Analysis) Puget Sound
    Project, Seattle, Washington in partial  fulfillment of

           EPA Interagency Agreement No. D6-E693-EN
                  Program Element No. EHE625-A
                   This study was conducted
                    as part of the Federal
                Interagency Energy/Environment
               Research and Development Program
                         Prepared for
           OFFICE OF ENERGY, MINERALS, AND INDUSTRY
              OFFICE OF RESEARCH AND DEVELOPMENT
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                    WASHINGTON, D.C.  20460
                        September 1979

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                         Completion Report Submitted to
                   PUGET SOUND ENERGY-RELATED RESEARCH PROJECT
                      MARINE ECOSYSTEMS ANALYSIS PROGRAM
                      ENVIRONMENTAL RESEARCH LABORATORIES

                                      by

                    Pacific  Marine  Environmental  Laboratory
                      Environmental  Research Laboratories
                National  Oceanic  and Atmospheric  Administration
                          7600 Sand Point Way N.E.
                          Seattle,  Washington  98115
     This work  is the result of research sponsored by the Environmental
Protection Agency and administered by the Environmental Research
Laboratories of the National Oceanic and Atmospheric Administration.

     The Environmental Research Laboratories do not approve, recommend,
or endorse any proprietary product or proprietary material mentioned
in this publication.  No reference shall be made to the Environmental
Research Laboratories or to this publication furnished by the
Environmental Research Laboratories in any advertising or sales
promotion which would indicate or imply that the Environmental
Research Laboratories approve, recommend, or endorse any proprietary
product or proprietary material mentioned herein, or which has as its
purpose an intent to cause directly or indirectly the advertised
product to be used or purchased because of this Environmental Research
Laboratories publication.
                                     it

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                                   CONTENTS


 Figures	   ,v
 Tables	!  .  !  !  !   vi
 Abstract	'.!."!!!!!!!!!!!  vii
 Acknowledgments  	  i  !!!!!!!!!!!!!!  iviii

 1.   Introduction   	    j

 2.   Conclusions  	    3

 3.   Sampling  and  Laboratory  Methods  	    5

 4.   Results and Discussion   	          8
     4.1.   Physical  Characteristics	...........'.    8
     4.2.   Oceanic Intrusions and  Indicator Species	.'!!.'    8
     4.3.   Phytoplankton  Distribution   	  ]    8
           4.3.1.   Phytoplanktonic  Biomass	'.'.'.   10
           4.3.2.   Phytoplankton Species Composition  	   14
     4.4.   Microzooplankton Distribution 	   20
     4.5.   Zooplankton Distribution	  .  .  .   21
           4.5.1.   Zooplanktonic Biomass	!  !  !  !   22
           4.5.2.   Zooplankton Species  Composition  	   26
     4.6.   Ichthyoplankton Distribution 	   28

 5.   References	32


 APPENDICES *

    A.     Pigment  Distributions, Strait of Juan de Fuca,
               February  1976 - October 1977	     Al
    B.    Tabulated Phytoplankton Data, Strait of Juan de Fuca,
               February  1976 - October 1977	     Bl
    C.    Zooplankton Species and Major Groups, Strait of Juan de  Fuca,
               February  1976 - October 1977	     Cl
    D.    Tabulated Zooplankton Data,  Strait of Juan de Fuca,
               February  1976 - October 1977	       Dl
    E.    Tabulated Ichthyoplankton Data, Strait of Juan de Fuca,
               February  1976 - October 1977	     El
* Appendices on Microfiche inside back cover.

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                                   FIGURES
  1.  Area chart and station locations for Strait of Juan de Fuca
     cruises, February 1976 - October 1977	35
  2.  Chlorophyll a in the upper 50 m of the Strait of Juan de Fuca,
     1976 -  1977	36
  3.  Diatom  concentrations in the upper 1 m of the Strait of Juan de
     Fuca, 1976 - 1977	37
  4.  Dinoflagellate concentrations in the upper 1 m of the Strait of
     Juan de Fuca, 1976 - 1977	38
  5.  Concentrations of ciliates in the surface waters of the Strait
     of Juan de Fuca, 1976 - 1977	39
  6.  Zooplankton settled volumes.  Vertical  tows, 211 ym mesh size;
     total water column.   Strait of Juan de Fuca, 1976 - 1977  	  40
  7.  Zooplankton settled volume. Vertical  tows, 211 ym mesh size;
     top 100 m.  Strait of Juan de Fuca,  1976 - 1977	41
  8.  Zooplankton settled volumes, means  of grouped stations. Oblique tows
     (50-0 m), 333 ym mesh size.  Strait of Juan de Fuca, 1976 - 1977  .  42
  9.  Copepod abundance from vertical  hauls,  Strait of Juan de Fuca,
     February 1976 - October 1977; total  number collected per total
     water volume filtered, by cruise  	  43
10.  Pseudoaalanus spp.  (adults).  Number of animals nr3.  Station 2,
     Strait of Juan de Fuca, 1976 - 1977	44
11.  Pseudocalanus spp.  (adults).  Number of animals m~3.  Station 5,
     Strait of Juan de Fuca, 1976 - 1977	45
12.  Pseudooalanus spp.  (adults).  Number of animals m"3.  Station 8,
     Strait of Juan de Fuca, 1976 - 1977	46
13.  Pseudooalanus spp.  (juveniles).   Number of animals m~? Station 2,
     Strait of Juan de Fuca, 1976 - 1977	47
14.  Pseudooalanus spp.  (juveniles).   Number of animals m~3. Station 5,
     Strait of Juan de Fuca, 1976 - 1977	48
                                     iv

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15.  Pseudoaalanus spp.  (juveniles).  Number of animals nf3.  Station 8,
     Strait of Juan de Fuca,  1976  -  1977	49

16.  Acartia longiremis (adults).  Number of animals nf3.  Station 2,
     Strait of Juan de Fuca,  1976  -  1977	50

17.  Aaartia longivemis (adults).  Number of animals m~3.  Station 5,
     Strait of Juan de Fuca,  1976  -  1977	51

18.  Aeartia longiremis (adults).  Number of animals m~3.  Station 8,
     Strait of Juan de Fuca,  1976  -  1977	52

19.  Oithona simLlis (adults).   Number  of animals m~3.  Station 2,
     Strait of Juan de Fuca,  1976  -  1977	53

20.  Oithona similis (adults).   Number  of animals nf3.  Station 5,
     Strait of Juan de Fuca,  1976  -  1977	54

21.  Oithona similis (adults).   Number  of animals ra"3.  Station 8,
     Strait of Juan de Fuca,  1976  -  1977	55

22.  Calanus nwshallae (adults).  Number of animals m"3.  Station 2,
     Strait of Juan de Fuca,  1976  -  1977	56

23.  Calanus marshallae (adults).  Number of animals irf5.  Station 5,
     Strait of Juan de Fuca,  1976  -  1977  .	57

24.  Calanus marshdllae (adults).  Number of animals m~3.  Station 8,
     Strait of Juan de Fuca,  1976  -  1977	58

25.  Sagitta elegans.  Number of animals  m"3.   Station  2,
     Strait of Juan de Fuca,  1976  -  1977	59

26.  Sagitta elegans.  Number of animals  m"3.   Station  5,
     Strait of Juan de Fuca,  1976  -  1977	60

27.  Sagitta elegans.  Number of animals  m"3.   Station  8,
     Strait of Juan de Fuca,  1976  -  1977	61

28.  Number of ichthyoplankton taxa  caught  in  surface and  oblique
     net hauls, Strait of Juan de  Fuca, 1976  - 1977	62
                       »
29.  Concentration of fish eggs caught in surface and oblique
     net hauls, Strait of Juan de  Fuca, 1976  - 1977	63

30.  Concentration of fish larvae  caught  in surface and oblique
     net hauls, Strait of Juan de  Fuca, 1976  - 1977	64

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                                   TABLES


1.  Summary of sampling activities in the Strait of Juan de Fuca,
    February 1976 - October 1977	6

2.  Current reversals (intrusions) and presence of oceanic
    surface-living plankton species, Strait of Juan de Fuca,
    February 1976 - October 1977	9

3.  Diatom species in upper 1 m, Strait of Juan de Fuca	11

4.  Percentage Similarity values for phytoplankton in upper 1 m,
    Strait of Juan de Fuca	16

5.  Percentage Similarity values for station to station comparisons of
    all phytoplankton populations during Strait of Juan de Fuca cruises,
    1976 - 1977.  PS values >_ 60 are underlined	18

6.  Percentage Similarity values for station to station comparisons of
    diatom populations during Strait of Juan de Fuca cruises,
    1976 - 1977.  PS values >_ 60 are underlined	19

7.  Zooplankton settled volumes (ml m~3) from vertical tows (211 um mesh
    size) taken in the Strait of Juan de Fuca, 1976 - 1977	23

8.  Zooplankton settled volumes (ml rrf3) from oblique tows (333 \an mesh
    size) taken in the upper 50 m of the Strait of Juan de Fuca,
    1976 - 1977	25

9.  Ichthyoplankton organisms caught in surface and oblique net hauls,
    Strait of Juan de Fuca, 1976 - 1977	29
                                      VI

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                                   ABSTRACT

     The exploitation of Alaskan oil deposits and anticipation of increased
oil transport through the Strait of Juan de Fuca to Washington State refin-
eries have generated concerns about the effects of petroleum spillage on
local marine communities.  Although aspects of plankton research have been
actively pursued in Puget Sound and off the Pacific coast, virtually no pre-
vious quantitative investigations have been conducted in the Strait of Juan
de Fuca.

     The composition and distribution of phytoplankton, zooplankton, and
ichthyoplankton communities was studied during 13 cruises conducted in the
Strait of Juan de Fuca from February 1976 to October 1977.  Phytoplankton was
numerically dominated by microflagellate species during late autumn and
winter months.  During June 1976, a diatom bloom composed primarily of
Skeletonema oostatum was in progress, and chlorophyll concentrations as great
as 25 mg nr3 were measured.  Diatoms were also dominant in the spring and
summer of 1977, but no bloom similar to that of 1976 was encountered.
Ciliates numerically dominated the microzooplankton community, with oligo-
trichs and tintinnids the most abundant.  The settled volumes of net zoo-
plankton increased steadily through the late winter and spring.  The highest
levels coincided with the June 1976 phytoplankton bloom.  The most numerous
zooplankters were copepods, especially near-surface and surface-living
calanoids and cyclopoids.  The sporadic occurrence of a group of oceanic
surface-living plankton species was associated with documented oceanic
intrusions and current reversals.  The ichthyoplankton, composed principally
of fish larvae, were most abundant during the winter and early spring months.

     This report was submitted to NOAA's Marine Ecosystem Analysis (MESA)
Office as part of the Puget Sound Energy-Related Project sponsored by the
U.S.  Environmental  Protection Agency.
                                     vii

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                                ACKNOWLEDGMENTS


     The authors are grateful to their colleague Mr. David A. Tennant for his
assistance during many of the cruises.  We also wish to express appreciation
and thanks to Mr. Kenneth Waldron of the National Marine Fisheries Service
for providing data from the ichthyoplankton samples.

     This study was supported by the U.S. Environmental Protection Agency
through an interagency agreement with the Environmental Research Laboratories
of NOAA.
                                    viii

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                               1.   INTRODUCTION


     An important aspect of NOAA's Marine Ecosystem Analysis  (MESA)  Puget
Sound Energy-Related Project was to characterize the communities  of  the
inshore marine waters of Washington State.  With respect to the plankton,  the
least known major marine area is the Strait of Juan de Fuca,  which separates
Puget Sound from the Pacific Ocean.  The present study was conducted in  the
Strait during 1976 and 1977 to describe the seasonal distribution and
composition of phytoplankton, zooplankton, and ichthyoplankton populations.
This information will add to MESA's overall biological baseline,  and could aid
in monitoring and understanding the effects of possible petroleum discharges
associated with increased tanker transport through the Strait of  Juan de Fuca.
Data and interpretations are presented concerning species composition, phyto-
plankton biomass as indexed by chlorophyll concentration, zooplankton densities
in the water column and at the surface, and distribution of ichthyoplankton.

     The Strait of Juan de Fuca is a deep estuary connecting  the  inland marine
waters of Washington State with the Pacific Ocean (Fig. 1).  It is character-
ized hydrographically as a two-layered system with an annual  net  westward flow
of relatively fresh water in the upper 30 m and more saline oceanic  water
below.  The Strait receives a large influx of fresh water from drainages into
Puget Sound and the Fraser River,  which empties into the Strait of Georgia to
the north.  There are two periods  of high runoff.  The major  one  occurs in late
spring when snowmelt is at a maximum in the Cascade and Olympic mountain
ranges.  A smaller runoff period occurs during late fall and  winter  when pre-
cipitation is high.

     Physical oceanographic characteristics of the Strait of  Juan de Fuca have
been treated elsewhere (e.g. Herlinveaux and Tully, 1961; Cannon, 1978).  In
general, salinity dominates the density structure throughout  the  year.  During
the summer a thermocline coincides with the halocline to reinforce the stab-
ility of the upper layer.  In the winter, waters are either isothermal or the
upper layers tend to be slightly colder than deeper layers.  Tides and tidal
currents are considered to be important oceanographic components  of  the Strait
of Juan de Fuca system.  During flood tide, dense ocean water enters the outer
Strait and flows beneath the upper zone.  The inner Strait is a region of
exchange where brackish water contributed by the Strait of Georgia is mixed
to homogeneity and enriched with ocean water.  Part of this water returns to
the deep zone of Georgia Strait, and part escapes seaward in  the  upper zone of
the Strait of Juan de Fuca during ebb tide.  In addition to exchange with
Georgia Strait, Juan de Fuca water mixes vigorously with Puget Sound and Hood
Canal waters in the region of Admiralty Inlet during tidal flow.   Because the
Strait of Juan de Fuca is a positive estuary where strong tides mix  coastal
and inner basin waters, it is of interest to determine if the plankton com-
munities found there are mixtures  of coastal and embayment populations, or are


                                        1

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distinct from those in the source waters.  The information obtained also pro-
vides a basis for comparing future plankton observations and for designing
future research efforts.

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                                 2.   CONCLUSIONS

      Thirteen research cruises  were  conducted at about 6 to 8 week intervals
 during 1976 and 1977 to provide information on the seasonal distribution and
 abundance of planktonic organisms  in the Strait of Juan de Fuca.  Major
 groups examined included phytoplankton, micro- and macrozooplankton, and
 ichthyoplankton.

      Phytoplankton,  the major primary producers of organic matter in pelagic
 ecosystems, were  studied by biomass  estimation (indexed by chlorophyll a
 content)  and by direct species  count.  Pigment concentrations were highest
 during June 1976  at  the time of a  large spring phytoplankton bloom.  No large
 bloom was encountered in the Strait  during 1977, but it is possible that a
 bloom occurred  between sampling periods.  Major forms of phytoplankton included
 diatoms,  dinoflagellates, coccolithophorids, and miscellaneous microflagellates
 in  general, microflagellates were the dominant component of the phytoplankton
 community during  late autumn and winter months.  Diatoms contributed the
 major biomass portion during mid-spring to early summer; high concentrations
 were  also found during a fall bloom  off Neah Bay in 1976.  Dinoflagellates
 reached their maximum numbers during late summer and early autumn, especially
 at  stations east  of  Neah Bay.-   Coccolithophorids were rare except when intru-
 sions of  ocean  water flooded into the Strait.  An analysis of species similar-
 ity showed  the  structure of diatom communities to be non-uniform from one
 end of the  Strait to  the other  during any one cruise.  Often the variability
 in  percent  species similarity during a single cruise was as great as variations
 between cruises.

      Microzooplankton  is  thought to  be an important, and often overlooked,
 trophic link  between  the  smallest phytoplankton cells and the larger zooplank-
 ton.   in  the  Strait of  Juan de  Fuca, particle grazing ciliates such as oligo-
 tncns  and  tintinnids were most numerous.  Mesodinium rubrm, a ciliate that
 may derive  a  major portion of its nutrition from photosynthetic endosymbionts,
 was also  present in significant numbers.   Besides protozoans, metazoans such
 as juvenile crustaceans, trochophore larvae,  and rotifers occurred.   Maximum
 microzooplankton concentrations coincided with periods of high phytoplankton
 concentration during spring aod summer.

      Larger zooplankters are the major grazers of phytoplankton and  as such
 represent a critical  trophic intermediary between primary producers  and car-
 7nnn^ni;tnnrtiCUlr^ ?ommercial1y valuable fish.   In general, the biomass of
 zooplankton closely followed the seasonal  distribution of chlorophyll  concen-
 7nnni^nJn  t- "PP6^50 m of the s^ait  of Juan  de  Fuca.   That is, maximum
 zooplankton biomass levels were observed  in the  spring and summer.  Copepods
were always the most  abundant net-zooplankters,  and these  organisms  showed the
 same seasonal trends  as total  zooplankton volume.   Three  groups  of "oceanic"
copepods not usually  associated  with coastal  regions  were  identified  in the

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Strait of Juan de Fuca.  One group, composed of deep-living oceanic species,
is excluded from Puget Sound by the shallow entrance sill; a second group of
deep oceanic copepods found occasionally near the surface is present in Puget
Sound; and a third group of oceanic surface-living copepods was found in the
Strait during periods of ocean-water intrusions and current reversals.

     In contrast to the zooplankton, the highest concentrations of fish eggs
and larvae were recorded in late winter and early spring, prior to the period
of greatest phytoplankton productivity.  The number of fish larvae usually
exceeded the number of eggs present, probably because the most common larval
forms in the Strait of Juan de Fuca are demersal spawners.  Most larval
species showed no particular preference for the surface waters, but one group,
Hexagrconmos spp., was pleustonic.

     Of particular note is the unexpected presence of oceanic surface-living
phyto- and zooplankton species in the Strait.  These species occurrences were
well correlated with times of independently documented oceanic intrusions.
These intrusions can at times influence even the eastern portion of the Strait,
and their presence suggests a reevaluation of ideas regarding pollution dis-
persement that are based on net water transport assumptions.

     The Strait of Juan de Fuca is a dynamic estuarine system joining the
Pacific Ocean and the inland marine waters of Washington State and British
Columbia.  The structure of the plankton community at any one time is influ-
enced by the complex physical exchanges between these bodies of water as well
as the biological characteristics of individual species and groups of species.
Seasonal cycles outlined in this report can only be considered approximations
of natural events.  Short-term fluctuations could not be examined because of
the long periods between sampling.  Future investigations might profitably
concentrate on the winter-spring transition period, stressing the increase in
primary production and the coupling of zooplankton species productivity to
phytoplankton biomass.

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                      3.   SAMPLING AND LABORATORY  METHODS


     Thirteen sampling cruises to the Strait of Juan  de  Fuca  were  conducted
at intervals of approximately six weeks during 1976 and  1977.   Sampling
activities are summarized in Table 1.  In general, during  each  cruise  three
transects of three stations apiece were made across the  Strait  at  Port
Angeles, Pillar Point, and Neah Bay near Cape Flattery (Fig.  1).   Only the
Port Angeles line was occupied during cruise SF7603 due  to mechanical  failure
of the vessel.

     At every station occupied, an obliquely towed plankton net and a  pleuston
sampler were used to sample the zooplankton.  A double bongo net was used for
the initial three cruises for oblique tows, but because  of handling difficult-
ies, this was replaced by a single net of similar configuration (333 urn  mesh,
60 cm mouth diameter) suspended in a newly designed frame.  Like the bongo  net,
the new single net had no bridle or other obstruction in front, and the  mouth
was free to swivel to maintain the net in a plane perpendicular to the towing
direction.  The oblique net was towed from 50 m to the surface  while being
slowly retrieved.  For cruise SF7607 and all subsequent  cruises, a digital
flowmeter  (General Oceanics, Model 2030) was fitted to the net  frame to  more
accurately measure the volume of water filtered.  The pleuston  net, equipped
with a 333 ym net, was towed at the surface, away from the ship's  wake,  for
10 minutes.  The zooplankton samples were preserved with sodium acetate
buffered 4% formaldehyde and returned to Seattle for analysis.

     At each midchannel station (2, 5, and 8) only,  a bottle cast  and  a  series
of vertical closing-net hauls were made in addition to the oblique and
pleuston tows.  Niskin bottles (1.5 1) were used to obtain water samples at
0, 10, 20, 30, 40, and 50 m.  Subsamples were drawn directly to determine
chlorophyll and pheopigment content and the phytoplankton and microzooplankton
species assemblages.  Phytoplankton and microzooplankton subsamples were
preserved  in an acetate buffered  1.5% formaldehyde solution.  These were later
analyzed in the laboratory  using  the  inverted microscope technique described
by Uterm'ohl  (1931).  Pigment concentration was measured with a shipboard
fluorometer  (Turner, Model  111) following the discrete sample method of
Lorenzen (1966).  The vertical hauls were made with a 211 ym mesh, 60 cm
mouth diameter closing net.  Usual depth strata sampled were: near bottom to
100 m, 100 m to 50 m, 50 m  to 25 m, and 25 m to the surface.  Sampling inter-
vals were adjusted for shallower  stations.

     To compare the catch efficiency  of the bongo net with the single net
design and to examine the precision of these methods, a series of ten
alternating oblique tows was taken during cruise SF7705; five replicate
samples were obtained with  each net.  The total volume of plankton caught
per volume of water filtered was  determined for each sample; no significant

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TABLE 1.  Summary of sampling activities  in the Strait  of Juan  de  Fuca,
          February 1976 - October 1977.

No. of Samples
Cruise

SF7601
SF7602
SF7603
SF7604
SF7605
SF7606
SF7607
SF7701
SF7702
SF7703
SF7704
SF7705
SF7706
Date

23-24 Feb
5-6 Apr
17-18 May
28-30 June
3-5 Aug
14-16 Sept
12-15 Nov
11-13 Jan
22-25 Feb
5-6 Apr
1-3 June
25-28 July
3-5 Oct
Vessel No. of
Stations
O)
_o

Commando
Commando
Hydah
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose
Snow Goose


8
9
7
9
9
9
9
9
9
9
9
9
9
o
8
9
7
9
9
9
9
9
9
9
9
18
9
leuston
o_
8
9
7
9
9
9
9
9
9
9
9
9
9
(O
o
4-»
Ol

11
11
11
11
11
11
11
11
11
11
11
19
11
c
o
c
to
'o.
o
4-J
.c:
ex
18
18
18
18
18
18
18
18
18
18
18
22
18
icrozooplankton
s:
2
5
4
3
4
3
3
3
3
3
3
3
3
5
o.
o
o
.c
o
18
18
18
18
18
23
18
18
18
18
18
30
18
heopigments
0.
18
18
18
18
18
23
18
18
18
18
18
30
18
-P
co
10
O
l_
o
0
3
0
3
3
3
3
1
3
3
3
3
3
                   Totals:
114
123 114   147 238  42   251   251   31

-------
difference  (0.05 level) was found between the means of the two groups.

     Settled volumes of all zooplankton samples were determined.  Large or
otherwise conspicuous organisms were removed, counted, and identified at
least to major taxonomic group.  Fish eggs and larvae were delivered to the
Northwest and Alaska Fisheries Center of the National Marine Fisheries
Service for further identification.  Subsamples were obtained with a Folsom
plankton splitter (McEwen et al., 1954) and sorted entirely to major taxon-
omic groups.  Principal species and copepods were identified and counted.

     During cruises SF7602 and SF7604-SF7702, a hand-lowered CSTD (Inter-
ocean, Model 513A) was employed at the midchannel stations to collect salinity
and temperature information in the upper 100 m.  During subsequent cruises, a
Plessey Environmental  Systems CTD Model 4600 was used.

     Data collected are archived on magnetic tape and are available at NOAA's
National Oceanographic Data Center in Washington, D.C.

-------
                          4.  RESULTS AND DISCUSSION
4.1.  PHYSICAL CHARACTERISTICS

     CTD casts were made during 11 cruises.   The vertical  profiles  of temper-
ature, salinity and density are generally consistent with  the pattern describ-
ed by Herliveaux and Tully (1961).  During April (SF7602), the deeper waters
tended to be slightly warmer than overlying  layers.   For all  cruises  the
surface salinity increased in a seaward direction.   A well-developed  pycnocline
with a distinct surface layer in late June (SF7604)  coincided with  a  peak of
phytoplankton biomass and is probably an important factor  influencing the
development of the bloom.  Profiles obtained during  later  cruises clearly show
that salinity controls the density field. Although  surface waters  were warmed,
the lack of a well-defined halocline prevented the formation  of a shallow
stable layer.

4.2.  OCEANIC INTRUSIONS AND INDICATOR SPECIES

     The sporadic occurrence in the Strait of Juan de Fuca of a group of
oceanic surface-living plankton species (Table 2) was unexpected,  in  view of
the quasi-constant surface outflow.  In November 1976, a large bloom  of phyto-
plankton occurred off Neah Bay (Station 8) and was accompanied by typically
offshore phytoplankton and zooplankton species.  Physical  parameters  had been
independently monitored at that time and revealed an intrusion of relatively
warm ocean water in the Strait (Cannon, 1978).  During two cruises  in 1977,
there were no independent physical data available to supplement the occurrence
of some of these characteristically oceanic  species.  At other times  these
oceanic species were present only at or near times of documented oceanic
intrusions and current reversals (Table 2).   Thus, these species appear unique-
ly associated with oceanic intrusions and could act  as "indicators" of surface
oceanic water masses, which at times influence even  the easternmost limits of
the Strait.  In light of the existence of these surface reversal events,
thoughts about contaminants rapidly flushing out to  sea in the surface outflow
should be revised.

4.3.  PHYTOPLANKTON DISTRIBUTION

     There is little published information dealing directly with the  seasonal
distribution of phytoplankton in the Strait  of Juan  de Fuca.   The available
data are largely limited to the San Juan Archipelago (e.g. Gran and Thompson,
1930; Phifer, 1933; Phifer, 1934a; Thompson  and Phifer, 1936) and Puget Sound
proper (e.g. Hirota, 1967; Booth, 1969; Munson, 1969; Winter et al.,  1975;
Campbell et al., 1977).  Phifer (1933) found two major diatom maxima  in the
waters of the San Juan Islands.  These occurred from late  May to early June
and from mid-July to mid-August.  Phifer (1934b) also studied the  vertical


                                       8

-------
TABLE   2.   Current reversals (intrusions) and presence of oceanic
             surface-living plankton species, Strait of Juan de Fuca,
             February 1976 - October 1977.

ZOOPLANKTON PHYTOPLANKTON
ft
p
"C
11 8 I 1 1 -S

li II i 1 II ! 1 f 4 !l It 1 1 ll II Jl If
Reversals Cruises
Feb 16 - Feb 22 (1976) SF7601 (Feb 23-24)
Feb 28 - Mar 2
Mar 20 - Mar 30 SF7602 (Apr 5-6)
SF7603 (May 17-18)
SF7604 (Jun 28-30)
SF7605 (Aug 3-5)
SF7606 (Sep 14-16)
Nov 14 - Nov 19 SF7607 (Nov 12-15)
Dec 8 - Dec 9
Dec 14 - Dec 18
Dec 26 - Dec 28
Jan 1 - Jan 5 (1977) SF7701 (Jan 12-13)
Jan 14 - Jan 19
Feb 2 - Feb 3
Feb 5 - Feb 14 SF7702 (Feb 23-24)
SF7703 (Apr 7-8)
no
data
SF7704 (Jun 2-3)
SF7705 (Jul 26-27)
Aug 31 - Sep 2
Sep 6 - Sep 8
Sep 21 - Sep 25 SF7706 (Oct 3-5)
S3 '
X






X


X


X







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X




X


X


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X





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X

X




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X
X






S 
-------
 distribution of diatoms in  the Strait of Juan  de  Fuca  for a  single  cruise
 during July and reported that most diatoms  were found  in  the upper  25 m.
 Shim (1976) observed diatom populations  in  the Strait  of  Georgia, B.C.  and the
 eastern part of the Strait  of Juan de Fuca  and also  reported two major  diatom
 maxima.  He generally found a rapid increase in standing  crop in April,
 followed by a sharp decline in May.   A second  peak occurred  during  the  early
 summer months.   Winter et al.  (1975)  noted  that the  annual pattern  of phyto-
 plankton growth in  Puget Sound was dominated by several intense blooms  between
 early May and September and commented that  the onset of blooms in the main
 basin of Puget  Sound is late for  the  latitude  of  48°N.  They stated that algal
 concentrations  changed drastically within time periods shorter than two weeks.
 Munson (1969)  found incident light,  freshwater runoff, and  tidal range to be
 the  three factors most useful  in  predicting the onset  and disappearance of
 blooms in Puget Sound.   Campbell  et al.  (1977) identified wind stress as a
 fourth important variable.   These factors may  also act to control phytoplankton
 growth in the Strait of Juan de Fuca  where  tidal  currents, thermohaline pro-
 perties,  and wind stress  affect water column stability.  The formation of a
 stable upper layer  is  usually  prerequisite  to  the occurrence of a phytoplankton
 bloom because the average light intensity in a vigorously mixed water column
 is insufficient for sustained  growth.

 4.3.1.   Phytoplanktonic biomass

      Chlorophyll a  values integrated  over the  upper  50 m show that  a large
 spring  bloom was in  progress at all stations during  late June 1976  (Fig. 2).
 Point  values  as  high as 25 mg  Chi a nr3 were observed at that time  (see
 Appendix  A  for  vertical profiles  of chlorophyll and  pheopigments at all
 stations).   By  August,  pigment concentrations  had declined to prebloom levels.
 Progressively lower  levels were encountered at the two innermost stations (2 and
 5) through  January  1977.  At these stations, moderately increasing  chlorophyll
 values  were  noted during  the following spring and summer.   The outermost station
 (8) was the  site of a distinct autumn  phytoplankton bloom during November 1976,
 coinciding  with  a strong oceanic  intrusion.   Winter chlorophyll concentrations
 were  significantly greater at  station 8 than at stations 2 and 5 during both
 1976 and  1977.   No large phytoplankton bloom was observed  in the Strait during
 1977.   Surface  concentrations  in  the  range of only 1-2 mg nr3 were commonly
 measured.   It is possible that a  bloom did occur between sampling periods and
 was therefore not detected.

     Measuring the chlorophyll a content is  the only rapid method for estimat-
 ing the biomass of living phytoplankton cells in seawater.  Statistical  reli-
 ability of the chlorophyll technique  is very much  dependent on the total amount
 of pigment being analyzed, but precision (P) is better than 8% of any value
 exceeding 0.5 mg m~3.  The 95% confidence interval about a mean of n samples
 is equal to ± P rr»  (Strickland and Parsons, 1972).

     Statistical variability was briefly examined  during one cruise.  Six
bottle casts were made in quick succession to sample surface seawater at one
 location.  A 95% confidence  level  of ± 0.07  about  a  mean of 0.81  mg  nr3  was
calculated.  This measure of variability includes  errors in analysis as  well  as
patchiness in the imediate vicinity.
                                     10

-------
TABLE 3.  Diatom species in upper 1  m,  Strait  of  Juan  de  Fuca.


Aatinoptyahus splendens
Aotinoptyohus undula^us
Amphiprora gigantea
v. suleata
Asterionella japonioa
Asteramphalus heptaotis
BaoteTiastrim d&ticatulwn
Be~L1e?ochea malleus
Biddulphia aurita
B-iddulphia longiaruris
Bi-ddulphia longiorupi-s
v. hyalina
Ceratulina bergcmii>
Chaetooeros affinis
Chaetoaeros approximatus
Chxetoaevos bvewis
Chzetoaeros compressus
Chaetoaeipos concavicoimis
Chaetoceros constrictus
Chaetooeros convolutus
Chaetooeros danicus
Chaetoeeros debilis
Chaetoceros deoipiens
Chaetoaeros didymus
Chaetoaeros gracilis
Chaetooeros laainiosus
Chaetoaeros lovenzianus
Chaetoaeros radicans
Chaetooeros aecwM&us
Chaetooeroe similis
Chaetooeros sooialis
Chaetoaeros subseeundus
Chaetooefos teres
Chaetooeros tortissimus
Chaetoceros vistulae
Cooaoneis
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                                     11

-------
TABLE 3. (Cont.)




Corethron hystrix
Coscinodisous angstii
Coscinodisous asteromphalus
Coscinodiscus centralis
Coscinodiscus centralis
v. pacifica
Coscinodiscus concinnus
Coscinodisous curvatulus
Coscinodisous granii
Coscinodiscus lineatus
Coscinodiscus marginatus
Coscinodiscus nitides
Coscinodiscus oculus-iridis
Coscinodiscus radiatus
Coscinodiscus stellaris
Coscinodiscus wailesii
Cylindrotheca closterium
Ditylum brightwellii
Eucampia zoodiacus
Fragilariopsis spp.
Grammatophora marina
Lauderia borealis
Leptocylindrus danious
Leptocylindrus minimus
Licmophora abbreviata
Melosira sulcata
Navicula directa
Navicula distans
Nitzsahia deliaatissima
Nitzsohia longissima
Nitzsahia pungens
Nitzsahia seriata
Pleurosigma spp.
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                                     12

-------
TABLE 3.  (Cont.)


Rhisosolenia alata
Rhizosolenia alata
f. gracillima
Phizosolenia delioatula
Rhizosolenia fragilissima
Fthizosolenia hebetata
f. semispina
RhLzosolenia setigera
Rhizosolenia simplex
Rhizosolenia stoltevfothii
Rhoiaosphenia ourvata
Skeletonema oostatum
Stephanopyxis nipponica
Thalassionema nitzsohiodes
Thdlassiosira aestivalis
Thalassiosira bioculata
Thzlassiosira aondensata
Thalassiosiva decipiens
Thalassiosira exaentrica
Thalassiosira gravida
Thalassiosira lineata
Thalassios-ira nordenskioldii
Thalassioaira pao-ifica
Thalassios-ira polyohorda
Thalassiosira rotula
"Fhalassios-lva subtilis
Thalassiothrix fvausnfeldii
Thalaesiotkpix longissuna
Tropidoneis antaretiaa
polyahorda'
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                                     13

-------
 4.3.2.  Phytoplankton species composition

      Phytoplankton cells in the surface and 50 m water samples  from the mid-
 channel  stations were enumerated to provide information on the  spatial  and
 temporal  distributions of algal populations in the Strait  of Juan  de Fuca.
 Tabulated data from all  stations are included in Appendix  B. Chester et al.
 (1977) commented on the  statistical reliability of these data.   Phytoplankton
 groups found included diatoms,  dinoflagellates, coccolithophorids,  and  mis-
 cellaneous microflagellates.   Unidentifiable microflagellates often dominated
 a  community in terms of  absolute numbers,  but their relative biomass was not
 nearly as great since the size  of individual  cells was small  (5-10  ym).   Micro-
 flagellates could not be identified to  lower taxonomic categories  because of
 preservation distortions and  the limitations  of light  microscopy.

      Diatoms contributed much of the phytoplankton biomass,  especially  in the
 spring, because the average cell  size was  large.   Over the 2-year  study,  93
 species in 32 genera of  diatoms were identified (Table 3).   In  general,  diatoms
 were  most plentiful  from mid-spring to  early  summer, but high concentrations
 were  also observed  during the fall  bloom off  Neah  Bay  (Sta.  8)  in  1976
 (Fig.  3).   During mid-winter, Melosiva  suloata and Thalass-ionema nitzsoh-Lodes
 were  the  most numerous diatoms  encountered.   M.  suloata is  a  littoral species
 that  lives almost exclusively in  association  with  nearshore  substrates.   Parts
 of chains often break away and  occur in plankton collections.   Both M.  suloata
 and T. nitzsohiodes  were present  in the Strait throughout  the year.   By  late
 winter, species of Thalassiosira  joined the  plankton assemblage.  The bloom
 organism,  Skeletonema costatum,  first made a  modest appearance  during early
 spring.   A large bloom of S.  costatum accompanied  by high  concentrations  of
 Chaetocevos  spp.  and Thalassiosira  spp. was present in  the early summer  of 1976.
 No massive bloom was encountered  in 1977, but sizable  quantities of S. costatum
 were  observed  in late spring.   By late  summer, M.  suloata  and T. n-ltzsoh-Lod.es
 were  again im, ortant species.

      Dinoflagellates are also important components of  the  phytoplankton  commun-
 ity in the Strait of Juan  de  Fuca.   During the  investigation, 23 species
 representing  11  genera were identified.  Dinoflagellates were usually not as
 abundant  as  diatoms  (Fig.  4).  The  seasonal cycle  of abundance  at stations 2
 and 5  shows  increased dinoflagellate  populations during  the  late summer and
 early  autumn.   This  is consistent with the pattern commonly  seen in  Puget
 Sound.  Off Neah  Bay (Sta. 8), however, no such pattern was discerned.

     Coccolithophorids were infrequent members of  the  phytoplankton  community,
 but their  very  presence may be significant.   These phytoplankters are abundant
 in waters  off the Washington coast, but they  have not been observed  in Puget
 Sound.  Therefore, the occurrence of coccolithophorids is probably  indicative
 of oceanic intrusions in the Strait of Juan de Fuca, and they are one of the
 groups referred  to earlier  (Section 4.2.).

     Phytoplankton count data are in part analyzed as comparisons of the
 species composition of the samples.  The Percentage Similarity  (PS)  index
 (Whittaker, 1960) has proved to be  the most useful approach to determine how
alike samples are with respect to species composition.   The PS of two samples,
X and Y, is calculated as follows:

                                      14

-------
               PS
= 100 - 50 ( z  |x.  -  y.|  )  = z   min  (x., y.}  ,
where x. and y. are the percents of total individuals that belong to the i
taxonomlc category in samples X and Y, and n is the total number of categories.
Miller  (1970) used Monte Carlo computer techniques to show that PS is a down-
ward-biased estimator.  This bias decreases with increasing sample size and
decreases with decreasing diversity of the population.  That is, samples from
a population strongly dominated by one or a few categories will tend toward a
higher  PS.  PS is primarily sensitive to shifts in the more abundant groups.
Miller  (1970) found that with sample sizes of 2000 and 1000 individuals, a PS
as low  as 80% and 75%, respectively, could be obtained when comparing two
samples taken from the same populations.  Because many of our samples contained
fewer than 1000 individuals and because not all phytoplankton classifications
were of equal taxonomic weight, the acceptance level required to consider two
samples identical should be lowered somewhat.  The following criteria were
adopted:

          if PS >_ 70, the samples showed excellent agreement and were consider-
          ed to have the same population distribution;

          if 60 £ PS < 70, agreement was fair and it was likely that popula-
          tions were the same;

          if PS < 60, agreement was poor and samples probably contained a
          different phytoplankton community.

     The complete PS matrix (Table 4) allows station-by-station intercompari-
sons for all surface samples counted.  Values comparing stations 2, 5, and 8
from the same cruise can be useful indicators of the uniformity of phytoplank-
ton composition from along the east-west axis of the Strait (Table 5).
According to PS values, the algal composition was homogeneous during about half
the cruises.  Large numbers of microflagellates, however, were often present,
and their influence far outweighed that of less abundant species on the PS
statistic.  The result is an upwardly biased PS estimate.  The microflagellate
category was necessarily a composite of many species because preservation tech-
niques and ordinary light microscopy made positive identification impossible.
It was therefore decided to calculate a PS matrix restricted to diatom species.
The results (Table 6) show that the structure of the diatom communities is not
uniform throughout the Strait during any one cruise.  Rather, distinct spatial
variations exist with respect to the dominant species composition.  Station 5,
located approximately midway along the longitudinal axis of the Strait, was
somewhat pivotal  in that its diatom community sometimes resembled that at
station 2 and at other times resembled that at station 8.  The lack of homo-
geneous phytoplankton distributions makes inter-cruise comparisons tenuous,
and in some cases one may say that the variation in PS during any one cruise
is as great as the variation between cruises.  The observed variability is
probably linked to the circulation patterns and recent biological  history of
various source waters (e.g. Pacific Ocean, Puget Sound, Strait of Georgia)
contributing to the Strait of Juan de Fuca.


                                     15

-------
TABLE 4.  Percentage Similarity values for phytoplankton in upper 1 m, Strait of Juan de Fuca.
Cruise
Station
SF7601
SF7601
SF7601
SF7602
SFZ602
SF7602
SF7603
SF7604
SF7604
SF7604
SF7605
SF7605
SF7605
SF7606
SF7606
SF7606
SF7607
SF7607
SF7607
SF7701
SF7701
SF7701
SF7702
SF7702
SF7702
SF7703
SF7703
SF7703
SF7704
SF7704
SF7704
SF7705
SF7705
SF7705
SF77D6
SF7706
SF7706
Z
5
$
Z
5
8
2
Z
5
8
~i
5
8
2
5
8
2
5
8
2
5
8
2
5
8
2
5
8
5
8
2
5
8
2
5
_fi 	
SF7601 SF7602 SF7603 SF7604 SF7605
258258 2 258 258
95 67 95 97 88 57 3 23 21 95 95
71 96 97 90 53 3 24 21 94 94
68 69 78 54 3 25 21 67 67
98 89 53 3 23 21 96 97
90 55 3 24 21 96 96
56 3 26 22 87 88
20 41 39 55 54
44 55 33
79 23 23
22 21
98








95
94
67
98
96
88
b4
3
23
21
9>
98








SF7606
258
42
39
40
39
41
42
54
13
44
30
41
40
40








83
83
68
83
83
86
66
5
27
23
83
83
83
50







88
88
67
89
89
89
61
4
25
23
do
90
89
47
91







SF7607
258
81
77
67
76
78
79
67
3
26
24
78
78
77
48
83
82







49
46
51
45
47
48
66
3
26
24
47
47
46
46
52
51
60






27
27
28
27
27
28
30
7
37
30
28
28
28
35
31
30
32
31







-------
TABLE 4. (cont.)
Cruise SF7701
Station 258
SF7601
SF7601
SF7601
SF7602
SF7602
SF7602
SF7603
SF7604
SF7604
SF7604
SF7605
SF7605
SF7605
SF7606
SF7606
SF7606
SF7607
SF7607
SF7607
SF7701
SF7701
SF7701
SF7702
SF7702
SF7702
SF7703
SF7703
SF7703
SF7704
SF7704
SF7704
SF7705
SF7705
SF77Q5
SF7706
SF7706
SF7706
2
5
8
2
5
8
2
2
5
8
2
5
8
2
5
8
2
5
8
2
5
8
2
5
8
2
5
8
2
5
8
2
5
9
2
5
8
65
62
62
61
62
64
70
4
26
23
63
62
61
46
64
63
/2
71
30






38
34
39
J4
36
37
b3
3
25
22
34
34
34
4b
40
39
48
63
33
66





59
59
69
59
59
61
b/
b
27
26
59
60
60
44
62
62
62
49
35
62
41





SF7702
258
34
32
36
30
32
34
50
3
25
23
32
31
31
43
37
36
44
59
29
63
85
38





20
17
18
Ib
18
19
3b
J
18
18
18
17
17
24
20
20
28
43
18
48
63
??
69




60
61
72
60
60
61
b4
3
24
22
60
60
60
40
61
60
60
49
28
62
38
77
37
18




SF7703
258
45
44
54
42
44
53
67
12
35
32
43
42
42
54
46
45
51
62
32
61
55
49
52
38
4?




43
41
44
39
41
45
62
13
36
31
40
40
39
56
46
45
51
55
31
49
48
44
47
32
40
73



94
94
67
9)
95
87
54
3
23
22
97
97
97
39
83
89
76
46
29
61
34
59
31
17
60
43
40



SF7704
258
39
35
36
3b
37
38
62
20
47
39
36
35
35
57
42
41
47
47
35
44
48
40
45
28
3f>
57
59
Ifi



92
92
66
92
92
86
b2
2
21
20
92
92
92
37
81
88
76
45
27
5$
32
58
29
15
59
40
38
9?
33


23
23
23
23
23
23
24
4
25
24
24
23
23
24
23
23
24
23
30
24
24
?5
24
16
?3
24
24
24
24
22


SF7705
258
56
55
56
55
57
57
57
9
37
33
57
57
56
47
59
58
59
51
37
60
36
63
34
19
57
46
44
Sfi
41
55
?5


87
87
fi7
8/
87
87
54
4
24
23
87
87
87
41
83
87
77
46
28
63
34
6?
37
18
60
44
40
87
36
86
?3
61

79
79
67
79
79
81
55
3
24
23
79
80
79
42
81
81
78
47
28
m u» en
10 <*> «o
38
19
fil
44
41
79
37
78
?3
63
90

SF7706
258
86
86
67
86
86
87
56
5
26
23
86
87
86
44
84
88
80
49
31
64
36
64
34
20
60
45
42
Rfi
39
85
?3
66
90
85

62 94
62 93
63 66
62 97
62 95
62 86
53 52
5 2
25 21
23 20
62 96
62 97
62 98
40 38
64 81
64 88
63 76
46 45
33 27
61 60
35 32
62 58
30 29
17 16
60 59
42 40
39 37
62 96
35 33
62 91
25 23
60 56
64 87
65 79
65 85
62

-------
TABLE 5.   Percentage Similarity values for station to station comparisons of
          all  phytoplankton populations during Strait of Juan de Fuca cruises,
          1976-1977.  PS values > 60 are underlined.

CRUISE

SF7601
SF7602
SF7603
SF7604
SF7605
SF7606
SF7607
SF7701
SF7702
SF7703
SF7704
SF7705
SF77Q6
STATION COMPARISONS
2X5
95
98
—
44
98
50
60
66_
69
73
33
6J,
65
5X8
67_
90
--
79
97
91
31
41
18
40
22
90
62
2 X 8
n
89
—
55
98
47
32
62
37
43
24
63
85
                                     18

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TABLE 6.  Percentage Similarity values for station to station comparisons of
          diatom populations during Strait of Juan de Fuca cruises,  1976-1977.
          PS values > 60 are underlined.

CRUISE

SF7601
SF7602
SF7603
SF7604
SF7605
SF7606
SF7607
SF7701
SF7702
SF7703
SF7704
SF7705
SF7706
STATION COMPARISONS
2X5
28
65
--
52
59
37
53
80
79
61
4
26
30
5X8
77
62
__
75
58
74
7
19
11
46
1
69
17
2X8
24
86
__
69
47
29
14
16
29
41
4
21
28
                                    19

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4.4.  MICROZOOPLANKTON DISTRIBUTION

     The term microzooplankton embraces a large variety of protozoan and
metazoan organisms which are too small to be adequately sampled by conven-
tional plankton nets.  Although they are small (generally < 200 um), their
specific metabolic rates (reproduction, ingestion, nutrient recycling, etc.)
far exceed those of the larger zooplankton.  Their ecological role may there-
fore be significantly greater than biomass alone indicates, and they may be
an important trophic link between the smaller phytoplankton and larger zoo-
plankton.

     In the Strait of Juan de Fuca, ciliates numerically dominate the micro-
zooplankton community.  Oligotrichs and tintinnids, active phytoplankton
grazers, are usually the most abundant ciliate taxa.  A total of 26 tintinnid
species and 12 oligotrich species were identified from the surface waters during
the 2-year study.  The population peaks of most of these species (e.g.
tintinnids -- HeHcostomella subulatas Eut-intinnus spp.; oligotrichs —
Strombidium aon-icum,  S.  strobilus) usually coincided with periods of highest
biological activity during the spring and summer (Fig. 5).  However, certain
species, such as the tintinnid Stenosemella ventriaosa, were most abundant
during the winter months.   The distribution of S.  ventvieosa may be related to
some combination of temperature preference, lorica building requirements, and
nutritional needs.   Besides the particle-grazing ciliates, large concentrations
of Mesodinium rubrum were often present, especially at the innermost sites.
M. -cub-rum, derives its nutrition from photosynthetic endosymbionts and as such
occupies a distinctly different position in the pelagic food web of neritic
waters than do other ciliates.  Protozoans other than ciliates include the
heterotrophic dinoflagellate Noetiluea mil-Loris and various foraminiferan and
radiolarian species.   These were seen infrequently during the study.  Metazoan
organisms were also recorded.  Juvenile crustaceans, trochophore larvae,
mitraria larvae, and juvenile larvaceans were recognized.  Adult rotifers were
also fairly frequently encountered.  In general, metazoans followed a pattern
similar to the protozoans.   That is, they were usually most abundant during the
periods of high phytoplankton production.

     The data gathered verify the volatile "boom or bust" nature of many of
these species and reinforce the view that microzooplankton may react quickly
to increased phytoplankton concentrations in such a way as to limit and
control blooms of at least the smaller photosynthetic organisms.  Although
the general trends are clear, the rapid variation in community composition and
size limits the possible interpretations .  A better picture of the distribu-
tion of specific organisms as well as an understanding of interspecies rela-
tionships requires a more comprehensive sampling schedule in terms of both
time and space.  A more detailed report on the distribution of the microzoo-
plankton in the Strait of Juan de Fuca has been published (Chester, 1978).
                                     20

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4.5.  ZOOPLANKTON DISTRIBUTION

     Zooplankton are important components of the environment  in  terms of  their
biomass, their roles in the ecosystem,  and their probable sensitivity to  the
kinds of petroleum industry development and transport activity anticipated  in
the Puget Sound region.  Zooplankton are the major grazers of phytoplankton
and as such are a critical  trophic link between primary producers  and carni-
vores, particularly commercially valuable fish.  Zooplankton  include a  variety
of commercially important fish and shellfish as larval forms, and  the remaining
fractions are directly or indirectly food sources or predators.  Many marine
organisms are planktonic for their entire life cycle, but even organisms  not
usually thought of as plankton pass through early planktonic  life  stages.
Most benthic and nektonic organisms tave planktonic eggs and/or  larval  stages
and are, therefore, especially vulnerable to contaminants throughout the  water
column (Moore et al., 1973).  Zooplankton provide important mechanisms, other
than ocean currents, for redistributing pollutants, especially by  daily and
seasonal vertical migrations and through significant repackaging of suspended
materials into rapidly sinking fecal pellets.

     In general, the distribution (particularly the vertical  distribution)  of
Zooplankton is not narrowly fixed, but varies with season, location, illumina-
tion, time, hydrographic conditions, and endogenous factors.   Because  of  pre-
vious irregular space/time investigations, there is not much  information  on the
dynamics of plankton populations within the Strait of Juan de Fuca, including
seasonal cycles of species, species successions, recruitment, and vertical  dis-
tributions and migrations of Zooplankton.  Much is known about the kinds  of
plankton organisms in the Strait of Juan de Fuca, and, except for larval  stages
and a few large and important groups like cyclopoid copepods, the general tax-
onotnic problems are manageable.

     Compared to warm-water plankton communities, the fauna of the Strait of
Juan de Fuca region is not particularly diverse.  Nevertheless,  the net-zoo-
plankton  community here undoubtedly comprises  several hundred species.  The
zooplankton of the Strait has been  regarded as  a simple mixture of species,
oceanic forms becoming less important eastward, being replaced by coastal
species doing well under estuarine  conditions.  This  species mixture is  govern-
ed by complex factors, giving the Strait a unique quasi-permanent zooplankton
community which differs from that of the nearby Strait of  Georgia as well as
from Puget Sound.  Relatively few species can  be considered  principal   components
on the basis of numbers and mass, or their critical  roles  in the transfer and
conversion of matter and energy within  the ecosystem.

     It  is of value to determine the natural zooplankton  populations and levels,
and ultimately to  be able to detect changes  in  these  as they occur, and  then to
predict serious modifications in the ecosystem.  However,  this is always an
extremely difficult task and especially so  in  such a  complex area as the Strait
of Juan de Fuca.   This is primarily because  the Strait has water-mass  components
mixing rapidly between Puget Sound, the Strait of  Georgia, and the open  ocean.
Pelagic populations cannot be followed  and  resampled, especially between time
frames of several  weeks.  Even within stable water bodies  such as lakes, it is
difficult to track single planktonic populations.  Along  the Strait, at  any one


                                      21

-------
 time,  an  investigator may encounter the same basic plankton populations, but at
 each locality  these may be at a different stage of community and individual
 development.   Superimposed on this time variability is variability in depth.
 Species have broad depth preferences that often change with age, season, or
 even time of day.  Mixing water layers and lenses obscure  these depth rela-
 tions, but also add  complexity to the space-time relationships that are the
 basis  of the present study.

     A 2-year  study at 6-8 week intervals is not adequate to describe the limits
 of abundance of the zooplankton species in the Strait.  We have, however, out-
 lined  the basic yearly cycle, although highs and lows of short duration may have
 been missed.   We can also describe a typical zooplankton population, and suggest
 envelopes of abundance with depth and season for many species.  Unless catas-
 trophic, changes in abundance would be difficult or impossible to detect using
 the data of this survey.  The presence or absence of species may imply a funda-
 mental  change  in the environment, and we have noticed such "indicators" on a
 small  scale during winter current reversals (see Table 2); warm-water oceanic
 species were unexpectedly found then in the Strait.  A climatic shift could
 give the Strait a very different zooplankton population, but this would be
 accompanied by changes in physical characteristics.

 4.5.1.   Zooplanktom'c biomass

     Zooplankton samples collected during the 13 cruises in the Strait of Juan
 de Fuca have been processed and analyzed in the laboratory.  Sampling times
 varied; these are given in Appendix D.   Settled plankton volumes were used as
 an index of zooplankton biomass (Tables 7 and 8).  These volumes (Fig. 6-8)
 followed fairly closely the seasonal  cycle of chlorophyll  concentration in the
 upper 50 m, as might be expected, since the bulk of this zooplankton volume is
 composed of herbivores directly dependent upon phytoplankton.   Zooplankton
 volumes in the oblique tows (Fig. 8)  tended toward a fall-winter minimum
 (7 months, September through March) with values below 1 ml m"3, and usually
 less than 0.5 ml m~3.   Maximum zooplankton volumes were found  in spring and
 summer (5_months, April  through August) with values above  1 ml m~3 and as high
 as 2 ml m"3.   In the finer-mesh vertically hauled net (Fig. 6  and 7) the volumes
were somewhat higher,  although the trends were the same.

     Zooplankton volume data are useful to show fundamental cycles, but they
do not provide much insight into ecosystems.   Populations  under stress are often
 replaced by other populations, and a  measure of volume would not detect this
change; different species of equal volume may have very different roles and
 impacts.

     The seasonal  cycle and magnitude of zooplankton volumes appear similar to
those from other years observed by somewhat different methods  off the Washing-
ton coast and in the main basin of Puget Sound.  These comparisons are based on
the very few observations in each region (Hebard, 1956; Frolander, 1962).
                                     22

-------
TABLE 7.  Zooplankton settled volumes (ml  nr3) from vertical  tows (211 pm mesh
          size) taken in the Strait of Juan de Fuca, 1976-1977.

Cruise Date
SF7601 23-24 Feb
SF7602 5- 6 Apr
SF7603 17-18 May
SF7604 28-30 Jun
SF7605 3- 5 Aug
SF7606 14-16 Sep
SF7607 12-15 Nov
SF7701 11-13 Jan
SF7702 22-25 Feb
Interval
Depth (m)
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
Station 2
(100 m)
0.9
1.0
0.3
2.9
1.6
0.8
4.1
2.8
0.8
16.6
9.4
5.9
1.7
1.4
1.8
1.0
0.9
2.2
0.6
0.4
1.2
0.3
1.0
1.7
1.3
0.6
0.5
Station 5
(180 m)
2.0
2.4
0.4
0.7
1.3
0.4
0.7
0.7

. 3.0
7.4
4.5
3.2
0.6
0.7
0.9
0.9
0.7
0.7
1.7
2.5
0.7
1.4
1.3
2.5
0.3
0.5
0.4
1.1
1.0
0.6
0.4
0.6
Station 8
(250 m)
1.0
1.1
1.0
3.2
1.3
1.1
0.8
0.4

36.4
1.9
3.0
3.4
0.6
0.7
0.7
1.2
0.1
0.1
0.6
0.5
2.0
0.1
0.3
0.9
1.0
0.5
0.3
0.03
2.0
0.6
0.7
0.6
                                      23

-------
TABLE 7.  (Cont.)

Cruise Date
SF7703 5- 6 Apr
SF7704 1- 3 Jun
SF7705 25-28 Jul
SF7706 3- 5 Oct
Interval
Depth (m)
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
0-25
25-50
50-100
100-bottom
Station 2
(100 m)
0.7
0.9
0.2
1.0
1.4
2.5
3.7
1.7
2.1
1.3
1.0
1.7
Station 5
(180 m)
0.4
0.4
0.8
0.8
3.1
0.4
1.3
2.4
1.1
0.4
0.7
0.7
2.4
0.7
1.4
6.4
Station 8
(250 m)
2.4
0.4
0.6
0.7
4.3
0.3
1.8
1.0
1.0
0.3
0.6
0.8
0.7
0.4
0.5
0.7
                                    24

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TABLE 8.  Zooplankton settled volumes (ml m"3) from oblique tows (333 ym mesh
          size) taken in the upper 50 m of the Strait of Juan de Fuca,
          1976-1977.

Cruise

SF7601
SF7602
SF7603
SF7604
SF7605
SF7606
SF7607
SF7701
SF7702
SF7703
SF7704
SF7705
SF7706
Date

23-24
5- 6
17-18
28-30
3- 5
14-16
12-15
11-13
22-25
5- 6
1- 3
25-28
3- 5
Station No.

Feb
Apr
May
Jun
Aug
Sep
Nov
Jan
Feb
Apr
Jun
Jul
Oct
4
0.6
1.0
0.8
1.2
1.2
1.1
0.2
0.2
0.9
0.4
1.2
0.9
0.7
2
0.5
1.0
1.1
1.7
0.8
0.4
0.2
0.1
0.4
0.2
0.7
1.1
0.7
3
0.3
1.1
0.6
1.9
1.2
0.3
0.4
0.8
0.2
0.3
0.8
1.1
0.6
4
0.4
1.9

2.8
1.1
0.4
2.1
0.2
0.4
0.4
1.5
0.4
0.8
5
1.2
1.7

2.4
0.5
0.2
0.1
0.1
0.4
0.1
1.5
0.2
1.3
6
1.2
1.2

0.8
0.4
0.2
0.1
0.1
0.2
0.2
1.7
0.1
1.9
7

1.4

1.7
1.2
0.3
0.1
0.1
0.2
0.3
1.9
0.3
0.3
8
0.5
1.1

1.3
0.6
0.2
0.4
0.2
0.3
0.3
1.5
0.2
0.3
9
0.5
1.3

2.4
0.3
0.2
0.2
0.2
0.4
0.4
1.9
0.2
0.2
                                     25

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4.5.2.  Zooplankton species composition

     Zooplankton volumes are obtained relatively quickly and simply,  but  inter-
pretations are complicated by the irregular occurrence of phytoplankton.   Some
phytoplankters form long intertwining chains and do not settle from the sample,
but entangle Zooplankton to give the appearance of a large plankton volume.  A
better characterization of the zooplankton is given by the identification and
counting of specimens.  There was a substantial variety of taxonomic  groups
represented in the samples.  The most common groups were Copepoda,  Chaetognatha,
Polychaeta, Medusae, Siphonophora, Cladocera, Ostracoda, Amphipoda,
Euphausiacea, Decapoda, Chordata, and larval fishes.  See Appendix  B  for  a list
of species and major groups.

     The zooplankton of the Strait of Juan de Fuca and Puget Sound  are a  mixture
of cold-temperate species and (warm) transition-water species.  From the  zoo-
plankton retained by nets, there are more than 100 species.   None of  these
species is found only in the inland marine water system.  That is,  all of these
zooplankton species are also found offshore in the open ocean.  In  addition, a
great many species found offshore cannot enter or go beyond the Strait of Juan
de Fuca, or cannot maintain populations there for one reason or another.

     There is a group of 16 species (marked * in Appendix C) of large, deep-
living "oceanic" copepods, which in most cases were persistent components of
Strait zooplankton.  As expected, these copepods were most abundant in the
deeper samples and occurred most commonly at the westernmost stations.  These
species do not occur above 50 m, and they are unable to cross the shallow sill
at Admiralty Inlet; therefore, they are not found to the southeast  in Puget
Sound, Hood Canal, or Dabob Bay.  Apparently, this is a strictly mechanical
phenomenon, with the vertical distribution of a number of important oceanic
species limiting their horizontal distribution.

     Five other species (marked ** in Appendix C) of "oceanic" copepods,  with
a similar preference for depth but which are occasionally found at  or near the
surface, can cross the Admiralty Inlet sill and are found, generally as  juven-
iles, in Puget Sound and/or Dabob Bay (Hood Canal).  It is not known if  these
populations are entirely dependent upon periodic immigration, or if they  can
breed in the inland marine areas.

     A third group is of five "oceanic" surface-living copepods (Table 2);
their sporadic occurrence  in the Strait was unexpected in view of the quasi-
constant surface outflow.   Initially, these specimens were believed to be deep
strays entering the Strait at depth, but they were not seen in deep samples,
nor were they found in summer when they can be very abundant offshore.   Recent
physical evidence  (Cannon,  1978) suggested winter ocean-surface intrusions and
periodic current reversals.  The occurrence of the surface oceanic  species was
associated with or close to these reversals  (see Section 4.2.).

     The Copepoda  of the Strait of Juan de Fuca were represented by about 60
species.  Copepods were always the most abundant net-zooplankton, and copepod
numbers showed the same seasonal trends as zooplankton volumes (Fig. 6-9).  The
fall-winter period was characterized by a large number of zooplankton species,


                                     26

-------
but each species was in small numbers.  This period of high species diversity
was in contrast to the lower diversity of spring and summer, where about the
same number of species was present (not always the same species as in fall  and
winter), but where a few species were very abundant.  Zooplankton diversity,
therefore, shows an inverse relationship to zooplankton volume.  During the
spring-summer zooplankton volume increase, over 80% of the numbers were of  a
single copepod type (Pseudooalanus species), while during the fall, winter, and
early spring volume lows, this same copepod type often amounted to less than
50% of the numbers (Fig. 9).

     In addition to Pseudooalanus spp. (Fig. 10-15), the most abundant copepods
include the calanoid Aoartia long-iremis (Fig. 16-18) and the cyclopoid Oithona
similis (Fig. 19-21).  These animals can be present in high concentrations
(hundreds to thousands nr3) and probably play a key role in the conversion  of
plant material to animal substance.  Moreover, they are an important food web
link because of their high metabolic rates and energy turnover potential.  Of
the larger, common species of copepods, Calanus marshallae, a key grazer
(Frost, 1974), is most abundant during the spring and summer months; the adult
form virtually disappears from the water column in late fall and winter in  the
Strait of Juan de Fuca (Fig. 22-24).  The highest concentrations of this species
were found at station 8, with a maximum in April 1977 of 368 nr3 in the upper
25 m.

     Euphausids were not nearly as abundant as copepods, yet euphausids are a
critical link between lower trophic levels and the large carnivores (Parsons
and LeBrasseur, 1970).  Five species were found: Euphausia pacif-iaa, Thysanoessa
inermis, T. longipes, T. rasahii., and T. spinifera.  For the most numerous,
Euphausia pacifiaa, the data suggest a maximum or near-maximum during the late
spring-early summer months: 51 m~3 in the upper 25 m, station 2, May 1976;  and
123 m"3 at 100-50 m, station 2, June 1977.  Nevertheless, the 6-8 week time
intervals between cruises make it difficult to generalize.

     Four species of chaetognath were identified: Sagitta elegans, the most
abundant, S. lyra, S. sori.ppsaet and Eukpohn-La hamata.  While almost always
present, Sagitta elegans was highly variable in abundance throughout the 2-year
sampling period (Fig. 25-27).  The highest concentrations for this species  were
found during the spring and summer months (> 100 m~3) and in the surface layer.

     A number of amphipods were collected including species representing the
families: Calliopiidae, Lysianassidae, Hyperiidae, Lycaeidae, Oxycephalidae,
Phronimidae, Paraphronimidae, and Phrosinidae (see Appendix C).  No species
was found to be present in great numbers, but Parathemisto paaifiaa was con-
sistently the most abundant, reaching concentrations of 25-50 m~3 in the fall
of 1976 and 1977.

     The seasonal cycle, as outlined in this report, is only an approximation
of natural and variable events.  Short-term fluctuations (weekly/biweekly)  were
not examined at all, and between-year trends were not fairly examined.  Future
investigations of this type in the Strait of Juan de Fuca might look intensive-
ly at the winter-spring transition, noting particularly the increase in primary
production and the coupling of zooplankton species to chlorophyll.  Also, to
assess the impact of zooplankton in the ecosystem, there is a need to examine

                                      27

-------
 more closely the detailed depth distributions  of species,  especially  daily
 vertical  migrations.

      The most abundant zooplankton  species  are essentially the  same in all  three
 principal  inland marine areas:  the  Strait of Juan de  Fuca, the  Strait of Georgia,
 and Puget Sound.  However,  the  proportions  of  some of these vary with region,
 giving each area a characteristic zooplankton  community.   This  is clear with
 the various Calanus species,  all of which are  important herbivores.   In the
 Strait of Georgia, the most numerous of  all  net-zooplankton species is the
 large Calanus plimahrus,  a  cornerstone of the  ecosystem.   In contrast, C.
 plumohrus  is rare in  the  Strait of  Juan  de  Fuca  and Puget  Sound.  This is prob-
 ably a mechanical  phenomenon, since C. plumahrus seems to  require depths in
 excess of  300 m to complete its life cycle.

      In Puget Sound,  a smaller  Calanus   species,  C. paaificus,  is among the
 most abundant zooplankton.  Very few C.  plumchrus  or  C. paoif-iaus were found in
 the Strait of Juan de Fuca, but a third  species,  c. marshallae, of intermediate
 size is one of the most numerous zooplankton species.

      Because of these regional  communities,  it may  continue to  be necessary to
 examine separately the zooplankton  of each  principal  area.  Also, because of
 the physical  interchanges between the Strait of  Juan  de Fuca, the Strait of
 Georgia, and Puget Sound, the responses  of  the zooplankton  of one region will
 not be fully understood without an  understanding of the distribution and abun-
 dance  of the zooplankton  in the adjacent regions.

 4.6.   ICHTHYOPLANKTON  DISTRIBUTION

      Fish  eggs  and larvae are particularly  sensitive  to oil pollution because
 many forms  aggregate  at the surface.  Also, since reproductive  intervals are
 long relative  to  those  of other planktonic organisms, the  population recovery
 rates  may  be correspondingly slower.  Several species spawn only during one
 short  period of the year.   The  recruitment of such species might be seriously
 disrupted  by a  single  coincidental   pollution episode.  The  results of fish eggs
 and larvae  analyses are tabulated in Appendix E.

     During  the  study,  a total  of 49  taxa, representing 21 fish families, were
 identified.   Fifteen of these taxa  have commercial value (Hart, 1973;  Clemens
 and  Wilby,  1949).  They include salmon, sole, smelt, greenling, herring,  cod,
 and  ling cod (Table 9).  The greatest number of taxa occurred during late
 winter  and  early  spring (Fig.  28) in both the pleuston and oblique samples.
 The  greatest population densities of fish eggs  and larvae were also recorded
 in  late winter and early spring; they mark this period as one of active  spawn-
 ing  and recruitment (Fig. 29 and 30).

     It is evident from the large number of eggs captured by the pleuston
 sampler that many fish eggs aggregate in the extreme upper water layer.   For
 the  13 cruises, the average abundance of pleustonic fish eggs in the open water
 of the Strait of Juan de Fuca  was estimated to  be 100 million.   The greatest
density of fish eggs was observed in April  1977, when there were an estimated
one-half billion pleustonic eggs in  the Strait.  Estimates of the total  number
of fish eggs in the upper 50 m of the Strait of Juan de Fuca,  based on oblique


                                      28

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TABLE 9.  Ichthyoplankton organisms caught in surface and oblique net hauls,
          Strait of Juan de Fuca, 1976-1977.
             TAXON
      COMMON NAME
COMMERCIAL
VALUE (X)
LARVAE
   Agonidae
   Ammodytes hexacpterus
   Artedius spp.
   Bathylagus stilbius
   Bathymasteridae
   Cithariohthys spp.
   Clinidae
   Clicpea harengus pallasii,
   Cottidae
   Cyclopteridae
   Gadidae
   Gadus spp.
   Gasterosteus aouleatus
   Gibbons-la spp.
   Hemilepidotus spp.
   Eexagvamnos spp.
   Hexagraimos deaagramrus
   Hexagrammos lagocephalus
   Hexagrammos stelleiH,
   Hexagrarmos supero-iliosus
   loelinus spp.
   Isopsetta isolepis
   Lepidopsetta bilineata
   Leptoeottus armatus
   Lumpenus maculatous
   Lyopsetta ex-LZ-is
   Micvogadus proximus
   Ophidon elongatus
   Osmeridae
   Parophrys vetulus
   Pholis  spp.
   Pleuronectidae
   Platioht'hys stellatus
   Plei&onic'hthys  decumene
   pyotcmyotophim  thompson-i
   Pset'bic'kt'hyB melanostictus
   Psyohpolutes spp.
   Salmonidae
   Soorpaenioht'hys marmoratue
Sea-poacher
Sand-lance
Sculpin
Black smelt
Ronquil
Sand dab
Kelp-fish
Pacific Herring
Sculpin
Lump-sucker
Cod
Cod
Three-spined stickleback
Kelp-fish
Irish lord
Green!ing
Kelp greenling
Rock greenling
Whitespotted greenling
Fringed greenling
Sculpin
Butter sole
Rock sole
Cabezon
Eel-blenny
Slender sole
Tom cod
Ling cod
Smel t
Lemon (English) sole
Blenny
Flounder
Starry flounder
Curl-fin sole
Bigeye lanternfish
Sand sole
Sculpin
Salmon
Giant marbled sculpin
    X

    X
    X
    X
    X
    X
    X
                                     29

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TABLE 9.  (Cont.)
              TAXA
      COMMON NAME
COMMERCIAL
VALUE (X)
   Sebastes spp.

   Stichaeidae
   Theragra ehaleogrcama
   Zaniolepis latipinnis
OVA
   Engraulis mordax
   Hippoglossoides spp.
   M-icrostamus paei-f-Lcus
   Plewconioh-fhys spp.
   Pleui'onie'hthys deourrens
   Pleuronichthys ooenosus
   Tvaahypterus spp.
Rock-fish
Northern lampfish
Northern blenny
Whiting
Long-spined green!ing
Anchovy
Sole
Dover sole
Sole
Curl-fin sole
C-0 sole
Ribbon fish
    X

    X
                                      30

-------
 net  catches, averaged  1.3 billion.  Similar calculations for total fish larvae
 gave average values of about 100 million  pleustonic juveniles for the entire
 Strait of Juan  de Fuca (maximum of 650 million during February 1977), and
 estimates from  the oblique net data showed an overall average of 31 billion
 larvae in the upper 50 m.

     There are  apparently far greater numbers of larvae than eggs in the upper
 waters of the Strait.  This conclusions seems contradictory, but knowledge of
 the  life cycles of the dominant fish populations makes it more plausible.  Most
 of the common larval taxa found in the Strait of Juan de Fuca are demersal
 spawners {e.g.  smelt,  greenling, sculpin, herring, cod, blennies, ling cod);
 others (e.g. rockfish) are live bearers.  The only major group which produces
 pelagic eggs is the sole.  Therefore, the relative paucity of eggs in the open
 waters of the Strait is understandable because the common larvae encountered
 represent species that do not release pelagic eggs.

     The number of fish taxa present as eggs or larvae throughout the year and
 their abundances clearly show that the major spawning season in the Strait of
 Juan de Fuca is winter and early spring (Fig. 28-30).  The osmerids (smelt) were
 overwhelmingly  the most abundant larval type found in the upper 50 m, especially
 during late winter and spring.  Population densities approximating 2 m"3 were
 recorded during both 1976 and 1977.  The osmerids were captured primarily by
 the  oblique net, indicating that they had no great preference for the extreme
 surface layer.  Other common species showing no particular depth pattern
 included  Amnodytes hexapterus> Sebastes spp., Hemilepidotus spp., and members
 of the Cottidae, Gadidae, and Cyclopteridae.

     One other group merits attention.  Hexagrconmos spp.  (greenlings) were the
 most numerous larvae taken in the pleuston sampler.  They were only rarely seen
 in any oblique net samples, however.  Hexagrammids were only observed during
 the months of October through April.  According to Hart (1973), adults of the
 family Hexagrammidae are common bottom fish in shallow waters.  The diet of
young fish taken from British Columbian waters during spring included copepods,
 amphipods, oikopleurans,  and smaller fish.  The genus Eexagrammos provides an
 excellent example of demersal organisms whose larval stages are closely coupled
 to the surface and may be particularly susceptible to pollution by oily slicks
 and films.
                                     31

-------
                                5.  REFERENCES
Booth, B.C., 1969.  Species differences between two consecutive phytoplankton
     blooms in Puget Sound during May, 1967.  M.S. thesis, Univ. of Wash.,
     Seattle, 28 pp.

Campbell, S.A., W.K. Peterson, and J.R. Postel, 1977.  Phytoplankton production
     and standing stock in the main basin of Puget Sound.  Final Report to
     Municipality of Metropolitan Seattle, 132 pp.

Cannon, G.A., ed., 1978.  Circulation in the Strait of Juan de Fuca: some
     recent oceanographic observations.  NOAA Tech. Report ERL-399-PMEL 29:1-49.

Chester, A.J., 1978.  Microzooplankton in the surface waters of the Strait of
     Juan de Fuca.  NOAA Tech. Report ERL-403-PMEL 30.

Chester, A.J., D.M. Damkaer, D.B. Dey, and J.D. Larrance, 1977.  Seasonal
     distributions of plankton in the Strait of Juan de Fuca.  NOAA Tech. Memo.
     ERL MESA-24, 71 pp.

Clemens, W.A., and G.V. Wilby, 1949.  Fishes of the Pacific Coast of Canada.
     Fish. Res. Board Can. Bull., 68, 368 pp.

Frolander, H.F., 1962.  Quantitative estimations of temporal variations of zoo-
     plankton off the coast of Washington and British Columbia. J. Fish. Res.
     Board Can., 19: 657-675.

Frost, B.W., 1974.  Calanus marshallae, a new species of calanoid copepod
     closely allied to the sibling species C. finmarehiaus and C. glacial-is.
     Mar. Biol., 26: 77-99.

Gran, H.H., and T.G. Thompson, 1930.  The diatoms and the physical and chemical
     conditions of the seawater of the San Juan Archipelago. Publ. Puget Sound
     Biol. Sta., 7: 169-204.

Hart, J.L., 1973.  Pacific Fishes of Canada.  Fish. Res. Board Can., Ottawa,
     740 pp.

Hebard, J.F., 1956. The seasonal variation of zooplankton in Puget Sound.
     M.S. thesis, Univ. of Wash., Seattle, 64 pp.

Herlinveaux, R.H., and J.P. Tully, 1961.  Some oceanographic features of the
     Juan de Fuca Strait.  J. Fish. Res. Board Can., 18: 1027-1071.
                                     32

-------
Hirota, J., 1967.  Use of free-floating polyethylene cylinders  in  studies  of
     Puget Sound phytoplankton ecology.  M.S.  thesis, Univ.  of  Wash.,  Seattle,
     83 pp.

Lorenzen, C.J., 1966.  A method for the continuous measurement  of  in vivo
     chlorophyll concentration.  Deep-Sea Res., 13: 223-227.

McEwen, G.F., M.W. Johnson, and T.R.  Folsom, 1954.  A statistical  analysis of
     the Folsom plankton splitter, based on test observations.   Arch.  Meteorol.
     Geophys. Bioklimatol. Ser. A, 7: 502-527.

Miller, C.B., 1970.  Some environmental consequences of vertical migration in
     marine zooplankton.  Limnol.  Oceanogr., 15: 727-741.

Moore, S.F., R.L. Dwyer, and A.M.  Katz, 1973.   A preliminary assessment of the
     environmental vulnerability of Machias Bay, Maine to  oil  supertankers.
     Mass. Inst. Technol. Rep. No. MITSG 73-6, 162 pp.

Munson, R.E., 1969.  The horizontal distribution of phytoplankton  in a bloom  in
     Puget Sound during May, 1969.  Non-thesis master's report, Univ.  of Wash.,
     Seattle, 13 pp.

Parsons, T.R., and R.J. LeBrasseur, 1970.  The availability of  food to different
     trophic levels in the marine food chain.   In: Marine  Food  Chains, J.H.
     Steele, ed., Oliver and Boyd, Edinburgh,  325-343.

Phifer, L.D., 1933.  Seasonal distribution and occurrence  of plankton  diatoms
     at Friday Harbor, Wash.  Univ. Wash. Publ. Ocean., 1: 39-81.

Phifer, L.D., 1934a.  Phytoplankton of East Sound, Wash.,  Feb.  to  Nov. 1932.
     Univ. Wash. Publ. Ocean., 1: 97-110.

Phifer, L.D., 1934b.  Vertical distribution of diatoms in  the Strait of Juan  de
     Fuca.  Univ. Wash. Publ. Ocean., 1: 83-96.

Shim, J.H., 1976.  Distribution and taxonomy of planktonic marine  diatoms  in
     the Strait of Georgia, B.C., Ph.D. thesis, Univ. British Columbia,
     Vancouver, Canada, 252 pp.

Strickland, J.D.H., and T.R. Parsons, 1972.  A practical handbook  of seawater
     analysis.  Fish. Res. Board Can. Bull., 167: 310 pp.

Thompson, T.G., and L.D. Phifer, 1936.  The plankton and properties of the
     surface waters of the Puget Sounf region.  Univ. Wash. Publ.  Ocean.,
     1: 115-134.

Utermb'hl, H., 1931.  Neue Wege in der quantitativen Erfassung des  Planktons.
     Verh.  Intern. Ver. Limnol., 5: 567-597.

Whittaker, R.H.,  1960.  Vegetation of the Siskiyou Mountains, Oregon and Cali-
     fornia.  Ecol. Monogr., 30: 279-338.


                                     33

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Winter, D.F., K. Banse, and G.C. Anderson, 1975.   The dynamics of phytoplankton
     blooms in Puget Sound, a fjord in the northwestern United States.
     Mar. Biol., 29: 139-176.
                                     34

-------
...
                                                                                SAN JUAN ISLANDS
                                                   WASHINGTON
                                   Figure  1.  Area chart and station locations for Strait of Juan de Fuca
                                             cruises, February 1976 - October 1977.

-------
         500 r
         400 -
         300 -
                                                          O = STA 2
                                                          D = STA 5
                                                          A= STA 8
co
01
ot
jE
o
          100 -
                    M   A  M   J
                            J   A   S   0   N   D  J
                                           1976   |
F   M  A
1977
M   Jo  J
0   N  D
                         Figure  2.  Chlorophyll a in the upper 50 m of the Strait of Juan de  Fuca,
                                   1976-1977.

-------
ce
LU
t-
co
5
o
o
                                                                        O STATION 2
                                                                        A STATION $
                                                                        Q STATION 8
   J   F   M   A   U   J   J    AS3    :JDJ    FflA.MJJASONO
                                                1976 11977
                 Figure  3.  Diatom  concentrations  in the upper  1  m of the  Strait of Juan  de
                             Fuca, 1976-1977.

-------
co
CD
      u.
      o
      o
      o
         J   F   M   A   r1       J   AS
                                                                             O  STATION 2
                                                                             A  STATION 5
                                                                             Q  STATION 8
                                                     OJF.1AMJJASOND
                                                     '•97C.  1077
                         Figure 4.   Dinoflagellate  concentrations  in  the upper 1 m of  the Strait of
                                     Juan de Fuca, 1976-1977.

-------
                                                                                   £(10,500)
CO
10
         8000 r
         7000 -
                                                   O = STA 2

                                                   Q = STA 5

                                                   A= STA 8
             0
                   Figure 5.  Concentrations  of ciliates in the surface waters  of  the Strait of

                              Juan de Fuca,  1976-1977.

-------
ml/in
  FMAHJJASONDJ
                        Figure 6.  Zooplankton settled volumes.  Vertical tows, 211 ym mesh size;
                                   total  water column.  Strait of Juan de Fuca, 1976-1977.

-------
ml/m'
       M    A
                Figure  7.   Zooplankton  settled  volume.   Vertical  tows,  211 ym mesh size;
                           top 100 ra.   Strait of Juan de Fuca,  1976-1977.

-------
      ml/rn
ro
                        Figure  8.   Zooplankton settled volumes, means of grouped stations.  Oblique
                                   tows  (50-0 m),  333 urn mesh size.   Strait of Juan de Fuca, 1976-1977.

-------
        ] Pseudoaalanus  spp. (juveniles;


          Pseudbaalanus  spp. (adults


      &g| Oithona similis


          "alanus marshallae


        \j Aeartia longiremis


          MetT-idia luaens


          other copepods


500-
        MAMJJASONDJFMAMJJASO
                       Figure 9.   Copepod  abundance  from vertical  hauls,  Strait of  Juan de Fuca,
                                   February 1976 - October 1977;  total number collected per total
                                   water volume filtered, by cruise.

-------
           =  500 / irT
Depth (m)


— 25

— 50
                                                    1976
 — 100
                                                    1977
                                                                                                    Depth (m)
                                                                                                        0 -,
                                                                                                        25 _
                                                                                                        50 -
                                                                                                        100 -J
Jan
          Feb
                   Mar
Aor
May
June       July
Aug       Sept
Oct
Nov
                      Figure 10.  Pseudocalanus  spp. (adults).   Number of animals nf3.  Station 2,
                                  Strait of Juan de Fuca,  1976-1977.

-------
                = 500 /  m"
      Depth  (m)
      — 0
      _ 25
      _ 50

      _ 100
      — 180
                                         1976
Ol
                                                        1977
                                                                                          Depth (m)
                                                                                               0 _
                                                                                              25
                                                                                              50 -

                                                                                              100 _
                                                                                                             180 _
      Jan
Feb
Mar
                                    Apr
                               May
June
July
Auq
Sept
                                                                        Oct
                     Figure 11.  Pseudoealanus  spp. (adults).   Number of animals nr3.   Station  5,
                                 Strait of Juan de Fuca,  1976-1977.
Nov

-------
           =  500 / m~
Depth (m)


— 25
  . 50


_ 100
                                T
                                                   1976
    250
                                                   1977
                                                                                                    Depth (m)

                                                                                                         0 —
                                                                                                        25
                                                                                                        50
                                                                                                       100
                                                                                                       250  -J
Jan       Feb
                   Mar        Apr
May
                                                  June       Jun
Aug       Sept
Oct
                                                                                                      Nov
                      Figure 12,  Pseudocalanus spp.  (adults).   Number of animals m"3.   Station 8,
                                   Strait of Juan de  Fuca, 1976-1977.

-------
           = 400 /  m3
  Depth (m)
 r- 0
 — 25


 — 50
                                                  1976
 _ 100
                                                 1977
                                                                                                   Deoth (m)
                                                                                                         0 -
                                                                                                        25


                                                                                                        50
                                                                                                       100 J
Jan
Feb
Mar
                               Apr
                               May      June
                                       Jul v
Auci
Sent
Oct
Mov
                       Figure  13.  Pseudocalanus spp.  (juveniles).   Number of animals m~3,
                                    Strait  of Juan de  Fuca,  1976-1977.
                                                                                       Station  2,

-------
                = 400 / m3
       Depth (m)
       	 0

       _ 25

       — 50


       _ 100
       L_ 180
                                                         1976
                                T
                                                         1977
CO
                                                                                                   Depth (m)
                                                                                                        0

                                                                                                       25  _

                                                                                                       50  -
                                                                                                              100  -
                                                                                                              180  _
Jan
                Feb
Mar
Apr
May
                                                         June
July
                                                                       Auq
                                                             Sept
                                                                                                   Get
                                                                                                       Nov
                         Figure 14.   Pseudocalanus spp.  (juveniles).   Number of animals m~3,
                                      Strait of  Juan de Fuca,  1976-1977.
                                                                                             Station 5,

-------
                 =  400 / m3
       Depth (m)
       — 0
       	 25
       — 50

       	 100
                                                          1976
         f            T
       1— 250
10
                                                          1977
                                                                                                    T
                                                                                          Depth (m)
                                                                                               0  .
                                                                                              25  -
                                                                                              50  _

                                                                                              100  _
                                                                                                              250  J
                                                                                                             Nov
       Jan
—l—
 Feb
Mar
Aor
May
June
July
Aug
                                                              Seot
                                                              Oct
                            Figure  15.   Pseudocalanus spp.  (juveniles).   Number of  animals m"3.   Station 8,
                                         Strait  of  Juan de Fuca,  1976-1977.

-------
                  =  150 / m3
Depth (m)

.	  0
                                                          1976
       —  25
       —  50
       _  100
en
                                                          1977
                                                                                                    Depth (m)

                                                                                                          0 .


                                                                                                         25 .


                                                                                                         50 .
                                                                                                               100 -J
       Jan
          Feb
Mar
Apr
May
June
July
Aun
                                                                                 Seot
Oct
                                                                                                              Nov
                             Figure 16.  Aeartia longiremis (adults').   Number  of animals  m"3.  Station 2,
                                          Strait of Ouan  de Fuca,  1976-1977.

-------
           =  150 / m3
 Depth (m)
 — 0
 — 25
 — 50
    100
 _  180
                                1976
                                                   1977
                                                                       T
                                                                                Depth (m)
                                                                                      0 -|
                                                                                     25 -
                                                                                     50 -
                                                                                                        100 -
                                                                                                        180
Jan        Feb
Mar
Apr
                                         May
June       July
Aun
Sent
Oct
Nov
                    Figure  17.   Aeartia  longiremis  (adults).  Number of animals m~3.   Station 5,
                                 Strait of Juan de Fuca,  1976-1977.

-------
                 =  150
Depth (m)


_ 25
  • 50

— 100
                                                          1976
       — 250
                                                                                T          T
                                                          1977
en
ro
           T            T
                                                                                                      Depth (m)

                                                                                                         0 —
                                                                                                        25 _

                                                                                                        50 -
                                                                                                              100 -
                                                                                                              250
      ,lan
         Feb
Mar
                                     Anr
May
                                                   June
July
Auo
                                                               Sent
Get
Nov
                       Figure 18.   Aoartia  Zongirem-is  (adults).   Number of  animals m"3.   Station  8,
                                    Strait of  Juan de Fuca, 1976-1977.

-------
                 =  100 / m3
        Depth (m)

       r— 0



       — 25



       — 50
                                         1976
       — 100
                                      I
tn
CO
                                                         1977
                                                                                          Denth (m)
                                                                                                              25  _
                                                                                                              50  _
                                                                                                             100  _J
      Jan
Feb
Mar
                                    Apr
May
June
                                                   July
                                                    Auq
Sept
Get
-\—
 NOV
                         Figure  19.   Oithona  similis  (adults).  Number of animals  m"3.  Station 2,
                                      Strait of Juan de  Fuca, 1976-1977.

-------
                       100 / m3
          Depth  (m)
          i—  0
          —  25
          _  50
           —  100
          I—  180
                                                             1976
en
                                                             1977
                                                                                                    Deoth (m)
                                                                                                         0  _
                                                                                                        25
                                                                                                        50  -

                                                                                                       100  -
                                                                                                                 180
                                                                                                                —I—
                                                                                                                 Nov
Jan
Feb
Mar
Apr
May
June
July
                                                                        Auq
Sept
Oct
                              Figure  20.  Oithona similis  (adults).  Number of animals m~3.   Station 5,
                                           Strait of Juan de  Fuca, 1976-1977.

-------
                     =  100 / m3
          Depth (m)
            -  0
          _  25
          —  50

          —  100
                                1976
          L_ 250
                                                              1977
en
                                                                                Denth  (rr>)
                                                                                      0  -,
                                                                                     25  -

                                                                                     50  -

                                                                                    100  _
                                                                                                                  250  -J
          Jan       l:eb
Mar        Anr
                                                  May
June       July
                      Aun        Sent
Oct
                                                                                    Nov
                                  Figure 21.   Oithona  similis  (adults).  Number of animals m~3.   Station 8,
                                               Strait of  Juan de  Fuca, 1976-1977.

-------
                  =  125 / nT
en
Depth (m)
r— 0
— 25
— 50
— 100
no
adults
1976
Tno no
adults adults
1977 Depth (m)
0 — ,
25 -
no no 5n
adults adults
100 -
        Jan
Feb
Mar
Apr
May
June       July
Aug
Sept
                                                                                                  Oct
                                                                                          Nov
                             Figure 22.   Calanus marshallae  (adults).   Number of animals  m~3.  Station 2,
                                          Strait of Juan de Fuca,  1976-1977.

-------
                    =  125  / m°
           Depth (m)

          _. 0

            . 25

            - 50


          _ 100
          L_ 180
1976
                                     no
                                   ad ill ts
  no
adul ts
en
-vj
                                                              1977
                                                                                                        no
                                                                                                       adul ts
                                                   Depth (m)
                                                       0
                                                      25 _

                                                      50 -


                                                     100 _
                                                                                                                   180  J
                    Feb         Mar        Apr       May        June       July       Aun        Sent       Oct
                                                    Hov
                               Figure  23.  Calanus marshallae (adults).  Numbers of animals m~3.   Station  5,
                                            Strait of Juan  de Fuca,  1976-1977.

-------
                =  125 / nT
       Depth (m)

       — 0
       — 25
       _ 50
       _  100
                                          1976
       L-  250
                                                                                              no
                                                                                             adults
                                                                                                  no
                                                                                                 adul ts
en
00
                                                          1977
                                                                                            Depth  (m)

                                                                                                0 -i
                                                                                                25 -
                                                                                                50 _
                                                                                                               100  -
                                                                                                               250  -J
      Jan
Feb
Mar
Aor
May
June       July
Auq
Sept
Oct
Nov
                               Figure 24.   Calanus marshallae  (adults).  Number of animals m"3.   Station  8,
                                             Strait of Juan de Fuca,  1976-1977.

-------
                    =  50 / m°
          Depth (m)
          r~ o
          _ 25
          _ 50
1976
          _ 100
                                                            1977
en
                                                  Depth (m)

                                                      0 —|


                                                     25 _


                                                     50 _
                                                                                                                100
         Jan        Feb        Mar        Apr       May       June       July       Aug       Sept
                                         Oct        Nov
                                   Figure 25.  Sagitta elegans.   Number of  animals nr3,
                                               Strait of Juan  de Fuca, 1976-1977.
                                 Station 2,

-------
          =  50 /
 Depth (m)
 _ 0

  . 25

 — 50



 ~ 100
 l_ 180
          1976
                                                   1977
                                I
                                                            Depth (m)

                                                                 0 _
                                                                25
                                                                50 _
                                                                                                        100 -
                                                                                                        180 _
Jan        Feb        Mar        Apr
May
June       July       Aun        Sept       Oct
Nov
                                 Figure 26.  Sagitta elegans.   Number of animals  m"3
                                             Strait of Juan de Fuca,  1976-1977.
                                                   Station 5,

-------
          =  50 / m~
Depth  (m)

__ 0
  . 25
  . 50
— 100
                                                    1976
L_ 250
                                                   1977
                                                                                                      Depth (m)

                                                                                                          0 —|
                                                                                                         25 _

                                                                                                         50 -
                                                                                                        100 -
                                                                                                       250 —I
                                                                                                       —i	
                                                                                                       Nov
Jan
Feb
Mar
Apr
May
                                                   June
July
Auq
Sept
Oct
                              Figure 27.  Sagitta elegans.   Number of animals  m~3
                                           Strait of Juan  de Fuca,  1976-1977.
                                                                                          Station 8,

-------
                                                                                         0  PLEUSTON

                                                                                         Q  OBLIQUE
                20



                18



                16
              <
              x
                12
              o
CD
ro
00
z
3
z
10


 8


 6


 4



 2
                                                             0    J    F

                                                            1976  I 1977
                              Figure 28.  Number of  ichthyoplankton taxa caught  in  surface and oblique
                                          net hauls,  Strait of Juan de Fuca,  1976-1977.

-------
CT>
CO
                80
                          O  PLEUSTON

                          Q  OBLIQUE
              a.

              z
              o
                20
                  J   F   MAMJ    J    AS   ONDJFMAMJ    JAS   0
                                                             1976
1977
                              Figure 29.   Concentration of  fish eggs caught in  surface and oblique
                                          net hauls, Strait of Juan de Fuca,  1976-1977.

-------
CT>
                                                                            3(116)
                                                                                       O PLEUSTON

                                                                                         OBLIQUE
                      JFMAMJJASONDJFMAM
                                                                                                             0.8
                                                                                                             0.6
                                                                                                                 CD

                                                                                                                 O
<

l/>
•^
UJ
                                                                                                              0.2
                                                                                         J   J   A    S    0
                              Figure 30.   Concentration of fish larvae caught  in  surface and oblique

                                           net hauls, Strait  of Juan de Fuca, 1976-1977.

-------