United States
Environmental Protection
Agency
Office Of Water
(4504F)
EPA 842-R-98-004
November 1998
Office Of Water Proceedings
1994 Annual Meeting
Of The National Shellfisheries
Association (Shellfish Stock
Enhancement Session)
Hew Jersey
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OFFICE OF WATER PROCEEDING
1994 ANNUAL MEETING OF THE NATIONAL
SHELLFISHERIES ASSOCIATION (SHELLFISH STOCK
ENHANCEMENT SESSION)
TABLE OF CONTENTS
PREFACE
CHAPTER 1
CHAPTER 2
CHAPTERS
CHAPTER 4
CHAPTERS
CHAPTER 6
HISTORY AND CURRENT STATUS OF NEW YORK STATE 1
SHELLFISH ENHANCEMENT
SETTLEMENT AND RECRUITMENT OF BAY SCALLOPS, 8
ARGOPECTEN IRRADIANS (LAMARCK 1819), TO ARTIFICIAL
SPAT COLLECTORS IN THE WESTPORTRIVER ESTUARY,
WESTPORT, MASSACHUSETTS
i I
SHELLFISH STOCK ENHANCEMENT ON MARTHA'S VINEYARD 26
THE BAY SCALLOP RESTORATION PROJECT IN THE WESTPORT 35
RIVER
ENHANCING NEW YORK'S GREAT SOUTH BAY HARD CLAM 45
(MERCENARIA MERCENARIA) RESOURCE: DETERMINING
WHICH STRATEGY TO USE
SHELLFISH ENHANCEMENT PROGRAMS: ARE THEY ENOUGH 52
TO MAINTAIN A FISHERY RESOURCE?
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PREFACE
Each year the National Shellfisheries Association holds an annual meeting at which time
scientist, government officials, and resource managers participate in discussions about shellfish.
The participants come from around the nation. In 1994, the meeting was held in Charleston,
South Carolina.
This proceedings document contains articles from the presentations of the Shellfish Stock
Enhancement Session. It was compiled from submissions from each author. The final
compilation and editing was done by James Woodley of EPA and Gef Flimlin of NJ Sea Grant.
Additional copies can be obtained by from James Woodley, Oceans and Coastal Protection
Division, USEPA 4504F, 401 M St., SW, Washington, DC 20460.
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NSA1994 Proceedings Chapterl
CHAPTERl
HISTORY AND CURRENT STATUS OF NEW YORK STATE
SHELLFISH ENHANCEMENT
j , -
Gregg Rivara, Cornell Cooperative Extension, 3690 Cedar Beach Road, Southold, NY 11971.
Abstract:
As early as 1825 shellfish seed were transplanted into New York City waters from
Chesapeake Bay: From these early efforts Long Island Municipalities have utilized techniques to
increase the population of harvestable shellfish. Seed planting, spawner sanctuaries, agreements
with private mariculture firms, public and private relays, predator control and management areas
are used towards this end. Although many of these methods are not critically evaluated they
remain politically and publicly popular in most towns. Resource enhancement strategies used in
the marine district of New York State will be summarized and quantified. In addition, a new
method for evenly dispersing hard clam seed using a modified agricultural seed planter will be
described.
Introduction: > ;','
Five types of shellfish enhancement methods are or have been used on Long Island.
These are: seed planting/shell planting, relays/depuration, spawner sanctuaries/spawner relays,
predator controland a special case, the Green Seal bay scallop restoration. All twelve towns m
Nassau and Suffolk Counties have attempted at least one of these strategies in order to increase
the number of shellfish available to residents.
Although most of these programs are politically and socially popular, their cost
effectiveness is largely unknown. Only two towns perform annual hard clam surveys in part to
determine how much of a contribution cultured shellfish make to the fishery. Without at least
qualitative proof that these programs are worthy of continued funding by municipalities their
future is in doubt, especially in light of taxpayer unrest and the desire to downsize government.
Seed Planting/Shell .Planting:
As early as 1825 private transplants of oyster seed to New York were common. Seed was
purchased from the Chesapeake Bay area and moved to New York City waters or Great South
Bay. By the middle of the 19th century oystermen wanted more control over cultivated beds and
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NSA 1994 Proceedings Chapterl
Brookhaven Town in Suffolk County granted the first lease in New York State. In 1881,
probably due to pressure from wild oyster harvesters, Brookhaven seeded oysters on public
bottom. This was New York's first public aquaculture project. During the latter half of the 1800's
the rift between the fishermen and cultivators became known as "The Oyster Wars". This period
saw private .concerns take over almost all the underwater lands on the South Shore and East End
of Long Island. Some of today's baymen are still hostile to private mariculture firms due largely
to how their predecessors were nearly forced off the bays by monopolistic practices of a few
large firms in the late 1800's.
In 1909 the first recorded private transplant of 50,000 bushels of Massachusetts hard
clam seed resultedhi a 4:1 return. The first quarter of the twentieth century saw experimentation
with artificial propagation of oysters and hard clams. Wells and Glancy, two oystermen, were
the first to artificially spawn oysters in 1923. By 1926 Wells was spawning and setting both
oysters and clams in his Oyster Bay hatchery; by the early thirties Glancy was able to grow hard
clams from egg to 25 millimeters at the Bluepoints Company in West Sayville.
During 1955-56 New York State planted about 5,000 clams, a small number by today's
standards although the first public hard clam seeding project in New York. The late '50's and
'60's were a time of great strides hi hatchery technology. In 1958 the Bluepoints Company
started an experimental hatchery in West Sayville (South Shore) followed in 1962 by F.M.
Flower and Sons in Bayville (North Shore). In 1968 the notata shell marker was first used to
identify hatchery-reared clams. In 1970 Long Island Oyster Farms opened a state-of-the-art
oyster hatchery on the discharge lagoon of a large oil-fired power plant on Long Island Sound,
The heated effluent of the lagoon was used to increase growth rates of clams and oysters prior to
planting until 1991; the hatchery was closed in 1982.
Public seed programs became more sophisticated in the 1970's and '80's. Islip Town was
the first to undertake a truly modern clam seed program in 1975. In 1986 Islip built the first
municipal hatchery/nursery, primarily for hard clam production. East Hampton built their public
hatchery/nursery at Montauk with partial funding from New York State in 1989. This came at a
time when the bay scallop population was at very a low level due to brown tide and commercial
fishermen were banned from selling striped bass due to high PCB levels. The hatchery raises
hard clams, oysters and bay scallops and'is the largest in square footage of any town
hatchery/nursery. Southold Town contracted with Cornell Cooperative Extension in 1991 to
operate a hatchery/nursery at the Cornell-operated marine lab located in Southold. Note that all
three of these facilities were not purpose-built but were modified from other uses.
During the mid 1980's research on planting strategies versus predation was undertaken. It
was clear that evenly-dispersed clam seed had a better chance of surviving predation by foraging
crabs (New York's most voracious shellfish predator) than seed that was planted in clumps. In
1989, with funding from New York State, a hard clam seed planter was developed from a
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NSA 1994 Proceedings
Chapter 1
modified corn planter. The planter was shown to evenly disperse clam seed onto the bottom with
little damage to the seed. It has been used by Towns in Suffolk County to plant millions of clam
seed over many acres. This strategy should result in more clams surviving to be recruited into
the fishery while preventing "bonanza" harvests of high density plants by harvesters.
Summary of Long Island Town Modern Seed Planting Activities-1993
Town
Babylon
Brookhaven
East Hampton
Huntington
Islip
Oyster Bay
Riverhead
, Shelter Island
Smithtown
Southampton
Sbuthold
Date Program Started
1978
1978
1981
1981
1975
1982
1984
1981
1980
1979
1982
1993 Total Planted (thousands)
1,000
2,000
10,000
.
40,000
600
-1,000
250
200
100
800
Table!
Relays/Depuration:
An obvious method of enhancing the number of shellfish that are marketable in a given
area is to enable fishers to harvest shellfish from areas that have been closed to shellfishing. This
is allowed in three ways: relaying, depuration and conditional/seasonal harvest areas: Under
supervision, many bushels of hard clams, oysters and soft clams have been harvested from
closed areas in New York State since the 1920's.
Due to outbreaks of diseases related to eating raw shellfish, New York State started
sanitary inspections in 1913. Most of the suspect areas were around New York City, where raw
sewage was being dumped into the rivers surrounding Manhattan. The first chlorination plants
were opened in the early 1920's. These were outfitted with tanks so that harvesters might store
products without it becoming contaminated as was the case with "floating", where bushels of
shellfish were simply hung over the side of a boat or dock. Floating is still illegal in New York.
In order to coordinate sampling programs in producer states, the National Shellfish Sanitation
Program (NSSP) was founded in 1925. The last chlorinatipn plant was shut down in 1932,
probably due to lack of efficiency of such plants. . ~
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NSA 1994 Proceedings Chapter 1
True depuration, an intensive method of microbiologically cleansing, started on a pilot
scale in 1941. Chlorine was used as the cleansing agent. In 1964 the State used ultraviolet light
in depuration studies and a demonstration plant was built on Long Island in 1971. The required
period for depuration is 48 hours, and there are guidelines in the NSSP with respect to tank size,
numbers of shellfish per gallon, temperature, flow rate and other parameters to ensure depuration
takes place. The first commercial plant was opened on Staten Island in 1979 but closed four
years later due to management problems and lack of a steady clam supply. In 1993 a small plant
oh Long Island was operating at test capacity, but was closed in early 1994.
Relaying is an extensive process which in New York requires the relayer or transplanter
to place shellfish on approved lots (on the bottom or off-bottom in cages) for a minimum of 21
days. Unlike depuration, which can be conducted year-round, relaying is limited to warmer
months (generally April through October) and relaying cannot start until the receiving (clean)
Waters have reached 10 C for one week. In 1938 the first 1,500 bushels of clams were relayed
from Staten Island to Brookhaven Town. Intra-tbwn relays were popular during the 1960's and
70's until Baymen pressure in the late 70's ended most of these. The problem, say some
fishermen, was that when the clams are removed, mere is no broodstock left to create set. They
also felt mat relaying and depuration (especially with clams from Long Island rather than New
York City) took the pressure off politicians and regulators, to clean up waters.
In 1964 the transplants from western Long Island Sound were harvested by mechanical
(hydraulic dredges) means and all the clams went to public lands for the benefit of all permit
holders. By 1993 70% of the 58,000 bushels of transplanted clams were hand-harvested and 97%
went to private relayers. Relayed clams in the early 1990's represented between 25 and 33% of
total hard clam landings in New York, and this by a very small portion of licensed commercial
diggers.
Seasonal and conditional openings allow baymen to gain access to shellfish resources
during certain periods. In the case of seasonal openings, where water quality improves during the
fall and winter months, harvesting is allowed during this time. Conditional areas open only when
there is no rainfall of a certain amount, depending on the hydrography of the site. After a rain
event exceeding this minimum, the area is closed for a set period, again depending on what past
bacteriological samples have shown. Both seasonal and conditional openings may be limited not
only by the State Department of Environmental Conservation, but also by each town's shellfish
management authority.
Spawner Sanctuaries/Spawner Relays:
These two techniques attempt to increase the number of larvae in the water and hence the
number of juveniles that will be recruited into the fishery. Sanctuaries, which were started in
1938 are simply areas where large numbers of broodstock shellfish are placed. In New York,
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NSA 1994 Proceedings
Chi
most work has been done with the hard clam. Chowder clams are used due to their low cost and
high fecundity. They are also low in value so are inexpensive (on a per piece basis) and do not
attract poachers. The theory is that a high fertilization rate will occur due to males and females
in close proximity. Beginning in 1963 relays were performed for the same reason, but spawners
from cooler waters were brought in so that they would spawn out of sync with local populations.
It is thought that this stretches out the spawning season, increasing the chances of a successful
set. Despite years of trying, including hydrodynamic models to place broodstock in areas to
target their larvae to productive areas, sanctuaries are still unproven due to negative or non-
existent evaluations. Reasons for failure include the fact that even a sanctuary with hundreds of
bushels of spawners has a minuscule egg output compared to the native broodstock. Despite this
seemingly ineffective management method, it is still popular, probably because it is inexpensive
and appears to be making a positive impact. The special case of a total lack of broodstock, such
as the bay scallop recruitment failure in the mid 1980's in the Peconic Bays is where spawner
. sanctuaries have been shown to work.
Predator Control:
Predation on bivalve shellfish is thought to be the primary limiting factor with respect to
recruitment. Most techniques to control predation were developed by commercial firms, some
have been attempted by municipal enhancement programs. Li 1912, New York State made the.
destruction of shellfish predators mandatory by law. While the law does not cover some
crusteacea (e.g. lobster, blue crab), it is still a part of the environmental conservation law, though
not strictly enforced. ' '
Starfish mops were first used during the 1930's. This control method entangles the stars
in mop-like drags. The animals are removed by dipping the mop in either a brine solution or hot
water contained in a tank on an oyster boat's deck. Smaller vessels have been used, especially in
reseeding efforts. In these cases the stars are hand-picked off the mop. Even with a large oyster
boat hauling two dredges, the work of clearing a large area of stars is time-consuming. In the
late 1930's Butler Flower of P.M. Flower and Sons Company in Oyster Bay used quicklime to
control starfish. This innovation is still used today by some commercial firms when an outbreak
of stars is found. ,
During the 1940's Butler Flower developed his suction dredge. Working like a huge
vacuum, the dredge head removes a layer of bottom. The resultant slurry is pumped on board
and the predators are picked out while water, sediment and shell goes overboard. This device
requires a large vessel with a large pump and is used primarily for propping grounds for
planting.
In 1960 poisons were used to control crabs. Fish heads soaked in pesticides were strung
along the shellfish lot. Thankfully the technique was short-lived due to its high cost and the
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NSA 1994 Proceedings
potential for toxin accumulation in shellfish. Another, more passive approach that was successful
in Virginia was attempted in New York in 1983. The placement of aggregate (e.g. bluestone)
over seed clams was shown in Virginia to protect small clams from crab predation. A similar
trial hi New York failed to protect seed clams. It was thought that while the most abundant crab
in Virginia is the blue crab, smaller mud crabs do the most damage on small seed clams in New
York The stone was actually providing the mud crabs a refuge from their predators along with a
free lunch nearby.
During the early 1980's work was progressing hi Virginia and later in New York on
biological control methods. One animal found to protect clam seed was the oyster toadfish,
Opams iau. A 1986 study hi Smithtown Bay using tethered and fenced-in toadfish was
inconclusive. During the same period, a project examined differences in hard clam survival due
to subsurface versus surface planting, and high versus low density plants. While planting clams
under the substrate had no effect on survival, low density plants had better survival after two
weeks than high density plants. Foraging crabs will eat more clams hi a given time period if they
are close hi proximity to each other. It is not just density, but how evenly-dispersed they are.
This information was used hi designing a hard clam seed planter. Modified from a corn
planter, the clam planter was tested in.1989 as a better way to plant clams. Hand-broadcasting
seed clams results hi "clumpy" distribution. Results of the planter trials showed even dispersal of
the seed with little damage. It was tested hi both municipal settings, where a low density plant is
desirable (large acreage to cover, little or no predation control) as well as a commercial planting
which was much higher in density (smaller acreage, predation control). No long term trials have
been performed, where the actual survival over years is monitored and compared with hand-
planted clams.
Green Seal Bay Scallop Restoration:
This is a special case of shellfish enhancement, made necessary by the appearance and
perseverance of the "brown tide", a bloom of algae that is poor food for bivalve shellfish,
especially larvae. First seen in 1985, the blooms caused recruitment failure of bay scallops hi
most of the Flanders-Peconic-Gardiners Bay system. Beginning the next year, a group of
commercial fishermen along with university and extension personnel with a combination of
skate, county andlocal funding restocked areas with'hatchery-reared stock. Many of the plantings
either died from predation or subsequent brown tide events and by 1988, the commercial fishery
had crashed, going from a $2 million pre-bloom value to only $2,000.
In 1989, genetic work on juvenile scallops showed 25% of these were genetically similar
to the 1988 hatchery stock that was planted. By 1990, recruitment was up and there was some
signs of recovery. A Polydora (mud-blister worm) infestation along with another summer of
brown tide caused mortalities in 1991. During 1992 and 1993 (non-brown tide years) a slowly-
,!' , J'.j _ : '. I'''" , ' ' ' ' ' ". . , ' " ' .'
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NSA 1994 Proceedings Chapterl
improving commercial fishery was seen from east to west Over six million bay scallops were
planted over the life of this, project; much was learned about planting these shellfish. It was the
first time in New York State that hatchery-reared broodstock was used to assist in revitalizing a ,
shellfishery.
Recommendations for New York's shellfish enhancement programs:
There is a need to critically evaluate present programs, both town and state-funded.
Although once universally politically popular, some programs are under fire for being
inefficient, ineffective or both.. Only two out of twelve towns have an annual shellfish census,
which provides critical information to evaluate such programs as seed planting and spawner
sanctuaries. Funds must be targeted to what works best hi a given area, rather than the "shotgun"
approach of many present programs.
A facility exists on north-central Long Island where heated effluent is available for
shellfish culture during the late fall through late spring period. The Northport Power Station is a
large, four unit oil/gas fired plant that was designed with a shellfish farming component.
Unfortunately, a fire in 1991 destroyed the entire environmental center where shellfish nursery
culture was taking place. A coalition of Long Island Towns have approached the plant's owner,
the Long Island Lighting Company about utilizing the site. Negotiations are ongoing. The
effluent lagoon would complement municipal hatchery production by allowing late (fall) spawns
and "runts" to grow to a large planting size by summer.
Relay sites in western Long Island Sound and around New York City are under heavy
harvest pressure. The New York State Department of Environmental Conservation recently
completed a Generic Environmental Impact Statement for the relay program. Mention is made
there of "sustainable harvests", and the old theory of reducing shellfish populations as much as
possible in closed areas is no longer espoused. Along those lines, public depuration should be
explored. While private depuration in New York has experienced failure, a public plant with a
larger supply base and some government support could work.
; The clam seed planter needs to be evaluated and fine-tuned so that its use may be
increased, especially among Long Island Towns growing millions of hard clams each year. In
addition, the need is still strong to educate the general public, commercial and recreational
shellfishers, regulators and policy makers through one-on-one meetings, baymen/advisory
committee meetings, fishermen's forums, newsletters and mass media. Only in this way can the
science and art of shellfish enhancement evolve in New York.
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NSA 1994 Proceedings . Chapter 2
CHAPTER2
SETTLEMENT AND RECRUITMENT OF BAY SCALLOPS,
ARGOPECfENIRRADIANS(LAMARCK 1819), TO ARTIFICIAL
SPAT COLLECTORS IN THE WESTPORT RIVER ESTUARY,
WESTPORT, MASSACHUSETTS
Karin A. Tammi1, Scott J.- Scares2, Wayne Turner3 and Michael A. Rice1
Abstract
In January 1993, The Waterworks Group initiated the Bay Scallop Restoration Project as
an attempt to restore the once prolific bay scallop population within the Westport River Estuary
in Massachusetts. This project is a multi-phased endeavor aimed at better understanding
recruitment failures of both natural stocks and introduced seed ofArgopecten irradians. The
main objective of this project is to assess juvenile recruitment (survival to > 4 mm) to artificial
spat collectors placed hi historically productive scallop beds and within close proximity to adult
spawner rafts. Spat collectors (2 to 4 mm plastic-mesh bags) containing monofilament were
Suspended on 28 to 35-meter floating long lines at 9 locations in the Westport River. A total of
1400 spat collectors were sequentially deployed on 89 long lines from June to August 1993 to
determine the timing of peak settlement and recruitment at each study site. The 1993 harvest
yielded 4000 scallops of varying shell heights ranging from 4 to 60 mm, with an overall mean of
36.9 mm. The variability hi shell height was related to the soaking tune of the spat collectors
which ranged from 68 to 152 days. The most productive long lines were located in the vicinity
of Corey's Island, Horseneck Channel and Canoe Rock. The greatest recruitment was observed
at Corey's Island which yielded 1882 scallops averaging 6.1 scallops per collector, with
individual long lines harvesting 18.2 scallops per collector.. This study indicates that A.
irradians will settle on artificial spat collectors containing monofilament, which may offer an
alternative tool for resource management and stock enhancement.
Introduction
The bay scallop, Argopecten irradians is an economically important bivalve harvested
'Department of Fisheries, Animal and Veterinary Science, University of Rhode Island,
Kingston, Rhode Island, 02881
2SRPEDD 88 Broadway, Taunton, Ma. 02780
3Water Works Group, P.O. Box 197, Westport Point, Ma. 02791
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NSA 1994 Proceedings Chapter!
commercially and for recreation in coastal communities along the Atlantic and Gulf coasts of the
United States. The total supply of bay scallop meat for the United States between 1983 and 1992
showed a gradual decrease in the annual harvest. In 1983, 2,338,000 Ibs of meat were landed
compared to 356,000 Ibs in 1992. Comparing recent landing records with 1991, the 1992 season
decreased by 82,000 Ibs (O*Bannon and Holliday, 1993). These nationwide landings indicate a
notable decrease in bay scallop stocks within the last decade which needs to be addressed.
Historically, Massachusetts has been the leading producer of bay scallops for New England and
the nation. Belding (1910) reported that commercial scalloping began in 1872 in Massachusetts.
The most abundant scallop beds were found along the south shore of Cape Cod, Buzzards Bay,
Martha's Vineyard and Nahtucket. Matthiessen (1992) reported that between 1951-1960
Massachusetts landed an impressive on average 915,000 Ibs of bay scallops annually. However,
between 1981- 1990, Massachusetts landed 23% fewer scallops from the earlier decade. Since '
Matthiessen's (1992) review, bay scallop harvests have declined further in the ,1990's.
Recruitment Failures
Sporadic recruitment failures have always been reported along the Atlantic coast, with
stocks constantly wavering from year to year (Belding, 1910). A precise cause for the
recruitment failure is not known, but evidence suggests that a number of factors are to blame
such as nuisance algal blooms (Bricelj et al., 1987; Summerson and Peterson., 1990; Tettelbach
and Wenczel, 1991), poor water quality (Stewart et al., 1981), industrial waste (Beaumont etal.,
1987), fishing pressure (MacFarlane, 1991), environmental conditions (Gaines and Ross, 1983;
Tettelbach and Auster, 1985), habitat loss (Stauffer, 1937; Cottam and Addy, 1947; Marshall,
1960; Fay et al., 1983) and predation (Peterson et al.,1989; Prescott ,1990; Pohle et al., 1991)
In general, it is believed that sporadic recruitment and declining stocks are related to the
bay scallop's life span of 20 to 26 months in New England (Belding, 1910; Outsell, 1931;
Roberts, 1978) and 12 to 16 months in the mid-Atlantic (Castagna, 1975). This short life span
coupled with the previously, mentioned factors are responsible for the decline in scallop
harvests. After consecutive years of poor recruitment, spawning stocks are reduced, thereby
adversely affecting the fishery over time. Most coastal communities are unable to rebound
without some type of management intervention. ,As a result, many communities implement
reseeding or transplanting programs to enhance the natural stocks (Burns, 1990;Tettelbach and
Wenczel, 1991). The most common practice is to purchase aquaculture seed from hatcheries.
Yet, hatchery reared seed may not survive well when transplanted or reseeded into.the estuary
prior to the winter season. Consequently, seed purchased to rebuild stocks may not live to
spawn (Tettlebach et al., 1990). Furthermore, the availability of seed at .affordable prices is often
a limiting factor in implementing a reseeding program in some small coastal communities
(Sherman, pers. com.)(Figurel:).
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NSA 1994 Proceedings
Chapter 2
Methods Available for Coastal Communities to
Enhance Bay Scallop Stocks
RESEEDING
Purchase seed
Aquaculture
Shellfish I
Propagation Areas i
Artificial Spat
Collectors
Figure 1.
Stock Enhancement: Artificial Spat Collection
As a consequence of fluctuating scallop stocks, many countries such as Japan, Tasmania,
New Zealand and Canada have devised various schemes to enhance natural stock. Methods such
as reseeding, artificial propagation and artificial spat collectors have been incorporated into
management plans. The collection of natural seed with artificial spat collectors, in addition to
reseeding, has effectively resulted in stabilizing the scallop fishery. The artificial spat collectors
have not been commercially utilized in the United States, but are widely used in Japan (Ito and
Byakuno, 1989), Tasmania, New Zealand (Bull, 1989), and Canada (Cropp, 1989) as part of
their overall scallop management program . In addition, countries such as Mexico (Verdugo and
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Oceans and Coastal Protection Division
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NSA1994 Proceedings ChaptCT2
Caceres-Martinez, 1991), Scotland (Fraser, 1991), Yugoslavia (Margus, 1991) and Ireland
(Burnell, 1991) are utilizing artificial spat collectors to study scallop populations and to assess
the potential for establishing a commercial fishery. With the advent of the artificial spat
collector, Japan has maintained a commercial scallop fishery by collecting scallop seed in areas
which had lost eelgrass beds (Ito and Byakiino, 1989; Ito, 1991).
Artificial spat collectors of similar designs have only been used for experimental
purposes in the United States. In North Carolina, Ambrose et al. (1992) used artificial spat
collectors of various colors and different surface size to determine factors influencing scallop
recruitment to the artificial collector. Researchers on Nantucket Island, Massachusetts _collected
over 40,000 scallop spat from 90 collectors placed in early July. After reaching 10 to 20mm, the
scallops were transferred to larger floating cages. Once the scallops reached 40 to 50mm in shell
height, scallops were redistributed onto the shellfish beds (Kelly and Sisson, 1983).
Nevertheless, very few New England coastal communities have attempted to utilize.
artificial spat collectors to investigate the settlement and recruitment of bay scallops to artificial
substrate or .as part of a management strategy for long-term stock assessment and enhancement.
Westport Estuary
The Westport River estuary harbors one of the most productive shellfisheries in
Massachusetts (Fiske et al, 1968). Historically, Westport has always enjoyed successful bay
scallop harvests, rarely experiencing large fluctuations in scallop stock (Figures 2 and 3). In
1985, Westport harvested a record 66,000 bushels of scallops which produced $ 2.5 million for
the local economy (Westport Annual Town Report, 1985). However, since the 1985 harvest,
only meager amounts of scallops have been harvested. The recent decline in this once prolific
resource questions the feasibility of future commercial scalloping in Westport. Furthermore, the
harvesting of clams, quahogs and oysters have been drastically reduced due to shellfish bed
closures from fecal pollution. The lack of a successful bay scallop set coupled with shellfish
closures have hurt the local and regional economy in southern New England. Faced with the
decline in scallop stocks, other methods of stock enhancement are needed to maintain bay
scalloping.
The purpose of this research is to investigate settlement and recruitment of bay scallops
to artificial spat collectors at various study sites throughout the Westport River estuary. The
goal of the Bay Scallop Restoration Project is to collect sufficient numbers of juvenile spat to be
placed in protective grow-out rafts at propagation areas in the estuary. The juvenile spat
collected from artificial collectors will be used as spawning stock. This preliminary research
provides insight into the feasibility of implementing artificial spat collectors and spawner rafts as
long-term enhancement tools that could help restore bay scallop stocks in the Westport estuary.
Office of Water 11 Oceans and Coastal Protection Division
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Chapter 2
Figure 2
Massachusetts
Shaded Areas Represent Historic Bay Scallop Beds
in the Westport River Estuary
(Fiskeetal.. 1968)
Figure 3
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NSA 1994 Proceedings
Chapter 2
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Material and Methods
During the summer of 1993, spatlines containing 20 to 25 individual spat collectors were
deployed at 9 study sites within the Westport Estuary (Figure 4). Artificial spat collectors
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NSA 1994 Proceedings
Chapter 2
consisted of (2mm - 4mm) 50 Ib. plastic mesh onion bags filled with monofilament (Figure 5).
Spat collectors were weighted in order to maintain a vertical soaking position. Horizontal
spatlines 28 - 35 meters long were sequentially deployed between June and August 1993. Each
spatline was color coded by date to aid in the determination of soaking time. A total of 89
spatlines and 1,400 spat collectors were deployed into both branches of the Westport River.
Spatlines were strategically located within close proximity to adult scallops held in spawner rafts
and in the vicinity of historic scallop beds seen in Figure 2. Each raft contained approximately
300 sexually mature adult scallops. Spatlines and collectors were retrieved in September and
October 1993. Spat collectors were opened and several quantitative and qualitative variables
Were analyzed from each collector, noting the location and time. Juvenile scallops were counted
and shell height (mm) was measured with hand held calipers (0.05 mm) precision. Fouling and
predatory organisms were also identified.
FLOAT
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WEIGHT
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JV.- FLOAT UP TO 2O-25 SPAT COLLECTORS
WEIGHT
WESTPORT RIVER SPAT COLLECTION
WEIGHT
Figure 5
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NSA 1994 Proceedings
Chapter 2
Results and Discussion
Spat Settlement .
Settlement of scallops to artificial spat collectors was successful in the summer of 1993.
A summary of each site is shown in Table 1. Of the 4,002 scallops collected, Corey's Island
displayed the highest recruitment of any study site, harvesting a total of 1,882 in 19 spatlines.
The average number of scallops/collector for this location was 6.1 (Figure 6). Individual spat
collectors deployed in July averaged 18.1 scallops/collector with the greatest overall recruitment
of 32 scallops in one collector. The second best collection site was Horseneck Channel which
harvested a total of 621 scallops, averaging 2.16 scallops/collector. Canoe Rock also displayed
favorable recruitment harvesting 491 scallops/collector and averaging 2.58 scallops/collector. In
general, the highest recruitment values were observed at Corey's Island, Canoe Rock, Hick's
Cove and Horseneck Channel spatlines deployed on July 4th and July 18th (Figure 7). The
analysis of the individual spatlines deployed at Corey's Island showed that July 4th had greater
recruitment than July 18th (Figure 8).
In summary, during the summer of 1993, bay scallop spawning in the Westport Estuary
may have occurred during late June and mid-July. Maximum recruitment estimates were
observed for those spatlines deployed the week of July 4th and July 18th with Corey's Island
representing the best study site, having the highest total recruitment value of 1882 scallops.
Summary of Westport River Research
Restsfts of 'Siifnmer i 903 . <
LOCATIONS
CANOE ROCK
COREYS ISLAND
HICK'S COVE
HORSENECK CH.
JUG ROCK
MASQUESATCH
RAM ISLAND
SOUTHARD SHORE
SPEAKING ROCK
TOTALS
#
SPATLINES
DEPLOYED
12
19
G
19
6
3
5
16
3
89
TOTAL
SCALLOPS
HARVESTED
491
1882
341
621
131
32
183
158
163
4002
MEAN
SCALLOPS
PER
COLLECTOR
2.58
6.1
3.04
2.16
1.51
0.65
3'.21
0.62
3.01
NA
MEAN
SHELL
HEIGHT
(mm)
37.1
25
32.2
29.8
26.9
30.7
31.5
30.4
29.1
36.9 mm
RANGE
OF
SOAKIN
GTIME
108-152
75-114
93 - 100
89-118
68
122
88
93-100
80
68-152
Table 1
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NSA 1994 Proceedings
Chapter 2
Recruitment of Bay Scallops to Artificial Substrate
in The Westport River
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Figure 6
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NSA 1994 Proceedings
Chapter 2
Recruitment of Bay Scallops to Spatiines in the Westport
Estuary Deployed from June to August
Results Sumni&i i 993-
.Mean # Scallops/Collector
Study Sites
OJUNE.6
JULY 4
n JULY 11
m JULY 18
JULY 25
OAUGUST 1
7,
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NSA1994 Proceedings " ' Chapter 2
Growth Measurements
The juvenile scallops harvested from the collectors ranged from 4 to 60 mm hi shell
height, with an overall average of 36.9 mm. The difference in shell heights related to the soaking
time of the long lines which ranged from 68 to 152 days. Canoe Rock displayed the largest
shell height averaging 37.1 mm with the longest soaking time of 152 days, whereas Corey's,
Island averaged 2! mm scallops with a maximum soaking time of 114 days (Table 1.). A
frequency distribution of spatlines deployed at Corey's Island exhibited a difference with respect
to the size classes observed. Spatlines deployed on the northwest side of Corey's Island were
smaller than the scallops collected from the northeast spatlines. However, northwest spatlines
were deployed on July 18th, one week shorter than the northeast spatlines which may explain for
the difference in shell height (Figure 8).
Lastly, normalization of the shell height measurements was conducted in order make a
comparison of possible scallop growth at each study site. Scallop heights were normalized to a
soalang time of 89 days. The 89 period represented the modal soaking time observed for all
spatlines. As a result, the mean shell height for all locations using the 89 days was
approximately 30.2 mm (Figure P.). Jug Rock displayed the largest scallop height
approximately 34 mm. The Masquesatch study area displayed a lower value which may relate to
having 3 spatlines and harvesting only 32 scallops with great variation in size.
('! . . . . ; ' ': ''.,, , ,
Normalizing of growth measurements only suggests possible growth potential and not an
actual growth rate of scallops within at the study sites. Since individual growth rates and
settlement times vary in estuary systems, determining these factors becomes difficult without
larval sampling and marking individual spats for growth monitoring.
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NSA 1994 Proceedings
Chapter 2
at
Total Scallops/Spstfea
Figure 8
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NSA 1994 Proceedings
Chapter 2
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40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Results of Slimmer 1983
y
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Study Sites
Figure 9
Fouling Index
A fouling index was created to access the "cleanliness" of the artificial spat collector.
Cojlectors were rated on a scale of 1 to 5, with 1 representing a clean bag and 5 a heavily fouled
bag. Collectors were closely examined with respect to this index. Spatlines and collectors with
longer soaking time were heavily fouled and given a rating of 5. A majority of the spat collectors
from Canoe Rock, Corey's Island and Horseneck Channel had soaking times over 100 days. As
a result, these collectors were given ratings ranging from 3 to 5. The remaining locations
displayed a variety of ratings from 1 to 5. The Jug Rock study site had the cleanest collectors
averaging 2.5 relating to the shortest soaking time of only 68 days.
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Chapter:
Fouling and Predatory Organisms
A variety of fouling and predatory organisms were collected outside and inside the spat
collectors. A summary of these organisms can be seen in Table 2. Organisms defined as fouling
in nature were mostly marine invertebrates and algae. Mogula spp:, Cionaspp., Styela partita,
Mcrocionaprolifer, Didemnum spp., Botryllus schlosseri, Crisia and Enteromorpha spp. were
among the fouling organisms that settled on the exterior of the collector bag and inside on the
monofilament.
Predatory organisms such as Carcinus maenas, Libinia dubia, Panopeaus spp., Tautog
onitisaad Opsonus tou were found inside the spat collectors feeding on Ponopeus spp., mud
crabs. It could not be determined whether these predators had also fed on the juvenile scallops
within the collectors. .
Artificial Spat Collector Contents
Names
Scientific Names
Carcinus maenas
LJblnia
Vase
spp
prolifera
.. .. _
Golden Star Tunicate Bofrylius schlosseri
... ..... F\ed P1""?1 ._ .._ ^ ....._ PJyptqsula spp. ~
Jointed Tube Bryozpans j_ _ Crisia spp.
!Hol'ow 9reen Weeds ~ " ~ ~ " Enteromorpha spp.
..Tau.?°9.... _. -: Tautog on ft/s_ , ~ ' '
9unPer. Tautogolabrus adspersus
Biennies Ophioblenniesatlanticus
Oyster Toad Fish_ _ Opsanus tail ~
Table 2
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NSA 1994 Proceedings Chapter 2
Conclusion
This study determined that A. irradians will settle on artificial spat collectors containing
rnonofilament in the Westport Estuary. Our results indicated that the maximum settlement time
occurred during mid-July, similar to other research in New England (Belding, 1910; Outsell,
1931; Kelley and Sisson, 1983). In addition, we determined that Corey's Island, Horseneck
Channel and Canoe Rock were the most productive study sites and therefore, the best areas to
deploy spat collectors hi the future. The greatest overall recruitment was observed at Corey's
Island yielding 1882 scallops. Historically, Corey's Island has been the most productive scallop
bed for the estuary known by researchers and local fisherman (Fiske et al, 1968; Sherman pers.
com;, 1993). Lastly, fouling and predation may influence scallop settlement and actual
recruitment estimates for all study sites.
This preliminary research displayed a high degree of variability with respect to the
number of spat collectors and spatlines deployed at each of the study sites. Along with the biotic
and physical factors, this variability greatly influenced the actual assessment of productivity,
settlement and recruitment values, and growth rate estimates determined for the 9 study areas.
Research conducted hi the future will focus on improving the methods from this 1993
experimental study. Li addition, larval sampling and monthly spat settlement will be monitored
thoroughly as will water chemistry, current and food availability. Applying these techniques
will further advance the accuracy of determining the optimal settlement and recruitment times of
scallops to artificial spat collectors. .
This research indicates that spat collectors may be a means to predict recruitment into the
bay scallop fishery. Secondly, juvenile scallops harvested from spat collectors could be utilized
for other grow-out applications to enhance natural stocks. Consequently, the implementation of
spat collectors into an overall management plan could be a method employed by coastal
communities to improve, stabilize and restore bay scallops in Southern New England.
Acknowledgements
This is publication #3117 of the Rhode Island Agricultural Experiment Station. This
project has been supported by the Westport Water Works Group and project H - 870 of the
Rhode Island Agricultural Experimental Station.
Literature Cited
Ambrose, W. G., H. C. Summerson, and J. Lin. 1992. Experimental tests of factors affecting
recruitment of bay scallops Argopecten irradians to spat collectors. Aquacult. 108 : 67 - 86.
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NSA 1994 Proceedings . . - Chapter2
fielding, D, L. 1910.,The scallop fishery of Massachusetts. Marine Fisheries, Ser. No. 3. Mass.
Div. Marine Fisheries.
Beaumont, A.R., Tserpes, G. and Budd, M.D. 1987. Some effects of copper on the veliger larvae
of the mussel, Mytilus edulis and the scallop, Pecten maximus (Mollusca, Bivalvia). Mar. Env.
Res. 21: 299-309.
Bricelj, V. M., J. Epp, and R. E. Maiouf. 1987. Comparative physiology of young and old
cohorts of, the bay scallop, Argopecten irradians irradians (Lamarack): mortality, growth, and
oxygen consumption. J.Exp. Mar. Biol.Ecol. 112: 73-91. " .
Brunell, G., (1991). Annual variations hi the spawning and settlement of the scallop Chlamys
baria on the west coast of Ireland.World Aqua. Soc. Special Pub, No. 1. pp 47 - 59.
Bull, M. F. 1989. Lessons and mistakes from recent trials of methods for spat catching and grow
out of scallops in New Zealand, pp. 253-263. In: M.L. C. Dredge, W. F. Zacharin and L. M. Toll
(eds.), Proc. Australasian Scallop Workshop, Hobart, Australia.
Burns, W. G. (1990). The Rhode Island scallop restoration program, pp. 89 -91. In :M. A. Rice,
M. Grady and M. L. Schwartz (eds), Proceedings of the First Annual Rhode Island
Shellfisheri.es Conference. Rhode Island Sea Grant. University of Rhode Island, Narragansett.
Castagna, M. 1974. Culture of the bay scallop Argopecten irradians, In Virginia. Mar. Fish Rev.
37(1): 19-24.
Cropp, D. A. 1989. Scallop culture in the Pacific region, pp. 134-153. Li: M.L. C.
Dredge, W. F. Zacharin and L. M. Toll (eds.), Proc. Australasian Scallop Workshop, Hobart,
Australia.
Cottam, C. and C. E. Addy. 1947. Present eelgrass conditions and problems on the Atlantic coast
of North America. In: Proceedings of the Twelfth Annual North American Wildlife Conference.
pp.387-398.
Fay, C. W., R. J. Neves, and G. B. Pardue. 1983. Species profile:life histories and
environmental requirements of coastal fishes and invertebrates ( Mid-Atlantic): Bay Scallop.
FWS/OBS-82/11.12. TREL-82-4. Oct. 1983, pp. 17.
Fiske,J. D., J. RCurley and R. P. Lawton. 1968. A study of the marine resources of the
Westport River. Commonwealth of Massachusetts, Division of Marine Fisheries, Monograph
Series#7. pp. 52. . :, ' ' >
Office of Water , 23 Oceans and Coastal Protection Division
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NSA 1994 Proceedings . Chapter!
Fraser, I. D. 1991. Settlement and recruitment in Pecten maximus (Linnaeus, 1758) and Chlamys
operations (Linnaeus, 1758).World Aqua. Soc. Special Pub. No.l. pp. 28 - 36.
Gaines, A. G. and D. A. Ross. 1984. Perception of the bay scallop fishery in southern
Massachusetts, analysis of a questionnaire. Woods Hole Tech. Report. WHO - 84 -38. Sept.
1984.35pp. ,
Outsell, I S. 1931. Natural history of the bay scallop. Bull. U.S. Bur. Fish., 45: pp:569-632.
Kelley, K. M. and J. D. Sisson. 1983. A simple spat collector for bay scallops, Argopecten
irradians. WHO - 84 -38: Proc. of Bay Scallop Fishery: Problems and Management: October
28,1983.p. 7.
Ito, H. 1991. Japan, pp 1017 - 1056. In S. Shumway (ed.) Scallops: biology, ecology and
aquaculture. Elsevier, New York.
Ito, S. and A. Byakuno. 1989. The history of scallop culture techniques in Japan, pp. 166-181.
In: D. Harding (ed). Scallop farming Blackwell Scientific Publ. LTD, Oxford, pp 233
MacFarlane, S. L. 1991. Managing scallops, Argopecten irradians (Lamarck, 1819) in Pleasant
Bay, Massachusetts: large is not always legal. World Aqua. Soc. Special Pub. No 1. pp.262 -
272. ' " ' '
Margus, D. 1991. Settlement of pectinid larvae in the Krka river estuary Yugoslavia. World
Aqua. Soc. Special Pub. No 1. pp.37 - 42.
Marshall, N. I960. Studies of the Niantic River, Connecticut, with special reference to the bay
scallop. Limnol. Oceanogr. 5: 86-105
Matthiessen, G. C. 1992. Perspective on shellfisheries in southern New England. TSC Coastal
Publication, No 4. The Sounds Conservancy, Essex, CT., 56 pp.
O'Bannon, B. K. and M.C. Holliday. 1993. Fisheries of the United States, 1992. U. S. Dept. of
Commerce, National Oceanic an Atmospheric Administration, National Marine Fisheries
Service.
Peterson, H. C., H C. Summerson, S. R. Fegley andR C. Prescott. 1989. Timing, intensity and
sources of autumn mortality of adult bay scallops, Argopecten irradians concentricus. J. Exp.
Mar. Biol. Ecol. 127: 121 - 140.
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NSA1994 Proceedings Chapter 2
Prescott, R. C. 1990. Sources of predatory mortality in the bay scallop, Argopecten irradians:
interactions with seagrass and epibiotic coverage. J. Exp. Mar. Biol Ecol. 144: 63 - 83.
Pohle, D. G., V. M. Bricelj, and Z. G. Esquivel. 1991. The eelgrass canopy; an above-bottom
refiige from benthic predators for juvenile bay scallops, Argopecteri irradians. Mar Ecol Prog
Ser. 74:47 -59..
Roberts, G. 1978. Biological assessment of bay scallop Argopecten irradians for maritime
waters. Can. Fish. Mar. Serv. Tech. Rep. No. 778. 13 pp.
», > '
Stauffer, R. C. 1937. Changes in the invertebrate community of a lagoon after disappearance of
the grass. Ecology. 18: 427 - 431
Stewart, L.L., Auster. P.J., and R. Zajak. 1981. Investigation on the bay scallop, Argopecten
irradians, in three eastern Connecticut estuaries. June - May 1981. Final Rep. to USDC, NOAA,
Milford, CT, pp. 15 - 16.
Summerson, H.C. and C. H. Peterson; 1990. Recruitment failure of the bay scallopArgopecten
irradians concentricus, during first red tide, Ptychodiscus brevis outbreak recorded hi North
Carolina. Estuaries. 13(3):322-331.
Tettelbach, S. T. and P. J. Auster. 1985. A mass mortality of northern bay scallops Argopecten
irradians irradians, following a sever spring rainstorm. Veliger 27 (4): 381- 38
Tettelbach, S. T. and P. Wenczel. 1991. Reseeding efforts and the status of bay scallop,
Argopecten irradians populations in New York following the appearance of brown tide J
Shellfish. Res. 10:273-280.
Tettelbach, S. T., C. F. Smith, J. E; Kaldy, T. W. Arroll, and M. R. Denson. 1990. Burial of
transplanted bay scallops Argopecten irradians irradians (Lamarck, 1819) in whiter J Shellish
Res. 9:127-134.
Verdugo, C. A. R. and C. C. Martinez 1991. Experimental spat collection of scallops
Argopecten circularis (Sowerby, 183 5), and Pecten vogdesi (Arnold, 1906) on a filament
substrate in Falsa Bay, B.C.S Mexico. World Aqua. Soc. Special Pub. No 1. pp 23-27.
Town of Westport. 1985. Annual Shellfish Report. Town of Westport, Massachusetts.
Personal Communications
Gary Sherman, Westport Shellfish Constable, Fall 1993
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CHAPTERS
SHELLFISH STOCK ENHANCEMENT ON MARTHA'S
VINEYARD
Richard Cl Karney
Martha's Vineyard Shellfish Group, Inc.
Oak Bluffs, MA 02557 '
Introduction
The Martha's Vineyard Shellfish Group, Inc. is a nonprofit consortium of the shellfish
departments of five Island towns attempting to manage the economically important public stocks
of quahogs (Mercenaria mercenaria), bay scallops (Argopecten irradiaTis)3 and oysters
(Crassostrea virgmica). Over the past 15 years, the shellfish management program has included
efforts to augment natural recruitment through the application of aquaculture techniques.
Foremost in this stock enhancemnent effort has been the local production of seed shellfish from
native broodstock in a solar assisted shellfish hatchery. Cost effective nursery methods have
been developed to grow quantities of seed shellfish of sufficient size to positively impact local
natural stocks.
The community shellfish resource development program is funded primarily with local
tax dollars appropriated at the town meetings of the five participating communities. The
Shellfish Group receives no financial assistance from the state. This grass roots program has of
necessity addressed the immediate concerns of the local populace. Cost effective production of
seed shellfish to improve local harvests has been the primary focus. The voters are reluctant to
fund "yet another study" of why shellfish stocks are in decline. The production of seed shellfish
to plant on public beds has been a more tangible and acceptable use of their tax dollars. With
the livlihoods of the local citizens at stake, a "shotgun approach" of trying any and all methods at
once has been used rather than more scientifically designed single variable experiments.
Consequently, a .degree of uncertainty is inherent in the observations. Investigators whose
funding is further removed from the local level are invited to take these preliminary observations
to a higher degree of scientific certainty.
Hatchery Culture
Seed shellfish used in the stock enhancement efforts are spawned and cultured in a solar
assisted shellfish hatchery. Within the 1,000 sq ft building, about 15 million seed shellfish
(quahogs, scallops and oysters) are produced annually. For a detailed description of the solar
hatchery operation see Karney, 1991.
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NSA 1994 Proceedings Chapters
Phytoplankton fed to the larvae are batched cultured using the Milford method. The Tahitian
strain of Isochrisis galbana. and Chaetoceros gracilis provide the bulk of the larval food. The
larger Thalassiosira weissflogii is fed to post set, especially scallops, which require
phytoplankton of larger cell size. Batch cultured Tetraselmis maciilata (TTM strain) is used for
conditioning broodstock. Also, a variation of the Wells-Glancy method is used to grow wild
cultures of phytoplankton which are used primarily for ripening broodstock. Except for stock
cultures which are grown in a hood under artificial light, all algae are cultured in natural light in
a passive solar greenhouse.
Broodstock, conditioned in the hatchery or collected naturally ripe in the field, are
spawned in pyrex dishes using thermal stimuli. The resulting larvae are grown in 400 liter
conicals in seawater filtered to five microns, heated to about 23 C and supplemented with
cultured phytoplankton. Throughout the two to three week larval period, the larvae are fed
daily. Every other day the larvae are drained, sized, culled and resuspended in new sea water.
With the onset of metamorphosis, quahog and scallop pediveligers are held on sieves in the
larval conicals with a downflow of water recirculated with an air lift. (Eyed oyster larvae are
remote set on shellbags at a site about five miles from the hatchery.)
Completely set quahogs and scallops are eventually moved to sieves with a trickle flow
of seawater bag filtered to five microns (Figures 2 and 3). As the juveniles grow, they are
moved to larger mesh sieves with stronger seawater flows filtered through 10, 25 and finally 50
micron bag filters. At about 0.5 mm the seed are given a flow of unfiltered raw seawater. The
quahogs are grown in upweller silos and the scallops in raceways. In these culture modes the
seed is rinsed daily and sized weekly.
Field Culture of Quahogs
In recent years, hatchery seed production has been increased with the use of field nursery
systems capable of handling smaller seed. Quahog seed is now routinely moved at 1 mm from
upweller silos to field nurseries. The quahog seed is planted in sand in both floating sandboxes
and wooden bottom boxes (Figures 4 and 5). These nurseries are designed to protect the seed
from crawling predatory crabs. Green crabs and mud crabs are major predators of the small
quahogs. The floating sandboxes suspend the seed off the bottom and away from the crabs. In
the bottom boxes window screen covers exclude the crabs. If the 1 mm seed is planted in the
nurseries in early July, it will reach about 20 mm by October. The seed is usually free planted in
public beds with a 60-70% survival. Protection for another growing season in bottom boxes
results in increased survival but is labor intensive as the larger seed must be thinned and many
more culture units constructed. Short wire fencing has proved effective in reducing predation by
whelks (Busycon carica) which can be significant predators on larger seed.
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Hatchery stocks have been selected for fast growth and genetically tagged for
monitoring. Annual shell growth rings may be used to estimate a quahog's age. Wild stock may
take five to seven years to attain legal littleneck size. The cultured stocks are selected for fast
growth and are legal for harvest at three to four years of age. About 80% of the quahogs
cultured in the hatchery are tagged with the brown genetic shell markings referred to as noJala.
Molata markings are rare in indigenous Island stocks. Cross breeding of nolata with native
broodstocks have given the hatchery stocks the genetic shell tag. One indication of the
effectiveness of the quahog stock enhancement efforts is the fact that some town shellfish
constables now report 20% of the harvest with notata markings. Natural sets of notala quahogs
have also recently been observed.
Field Culture of Scallops
At about 2 mm, seed scallops are moved from the hatchery raceways to field cages
anchored in the bay outside the hatchery. The cage nurseries are 6 feet long, 2.5 feet wide and 1
fopt deep (15 cu ft); and constructed of 2X3 lumber frames with various size plastic netting on
the sides (Figures 6-8). The 2 mm seed from the hatchery raceways are transferred to cages
with fiberglass window screen mesh at a density of about 100,000 scallops per cage. The
window screen fouls quickly and must be brushed clean daily. After about a week in the field,
the seed have grown enough that they may be transferred to a larger 3 mm vexar mesh cage at
about half the original density. Ideally, the scallops are eventually reduced to a density of
15,000 in 10 mm mesh cages. Under these conditions the scallops reach about 20 mm at 2
months of age and are broadcast into public beds known to be good natural scallop grounds.
Because of limited man power and rafting capacity, not all the scallops set in the
hatphery can be cultured in the cage nurseries. A portion of the set scallops are moved to the
field in biodegradable burlap bags. Post set scallops on hatchery sieves are presented with
swatches of burlap to which they readily attach. The scallop coated swatches are moved into
burlap bags suspended over eel grass beds from longlines and floats. The scallops quickly
spread themselves over the burlap bags which provide a source of attachment in warm surface
waters away from bottom dwelling predators. As they become crowded, the scallops drop off
and seed themselves hi the eel grass, this slow seeding over time may prevent the drawing of
predators sometimes associated with mass seeding events. In time, the self destructing burlap
nurseries decompose and deposit the remaining seed scallops in the underlying eel grass beds.
The use of the burlap nurseries is new to the program and its effectiveness is yet to be
determined.
The mobility of the scallop has made it more difficult to assess the survival of the seed
and effectiveness of the seeding techniques. Exploiting the naturally occuring variation in shell
color, strains of scallops genetically tagged for shell color have been produced and used to
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NSA1"4ProCeedingS Chapters
monitor survival. Orange shell scallops, rare at only 1.5% of a natural population sample, were
used as a hatchery tag for several years resulting in a noticeable increase in orange shelled
scallops in the local harvest. Orange shell color has been determined to be a dominant trait
(Adamkewicz and Castagna, 1988), so that the increase in frequency in the population was
probably not due only to the release of orange shelled seed but to the resultant increase in the
dominant gene in the population: It is believed that the anomoly of the rare occurence of the
dominant orange shell gene may result from increased predation pressure on brightly colored
shellfish by diving waterfowl (Elek, 1985). Presently, hatchery seed is tagged with striped shells
which may offer some camouflage advantage in eelgrass habitats.
Seed scallops often react to disturbances with a growth check on their shells. The
increased handling of the scallops in the hatchery and nursery systems "tag" the cultured stock
with numerous check marks. These, along with the shell color tags, have aided in the
recognition of hatchery stock collected from the wild population. Further, the cultured scallops
produce a distinctive deeper cupped, more convex shell form which is easily recognized.
Perhaps this more ovoid scallop results from crowding the juveniles, and should be further
investigated. Although the cupping may result in decreased shell height, adductor muscles are
comparable to natural stocks and thus do not affect the market product.
From these recognizable tags, cultured scallops have been recovered from the natural
population; sometimes in good quanities, other times not. In some cases .predation has been a
clear reason for the mortality. At least two of the more successful recoveries appear to be
associated with small seed released late in the season. Perhaps the small size of the seed late in
the season is out of sync with the predators. Further investigation is warranted.
In addition to the seeding of hatchery cultured stock, some efforts have been made to
manipulate the spawning of field populations. Spawning sanctuaries have been employed on a
number of occasions and at least once has coincided with a heavy "natural" set. A spawning
sanctuary is a surface floated shallow cage filled with several hundred scallops. In theory the
scallops in the sanctuary are held in close proximity and subjected to repeated wanning and
cooling stimuli in the surface water. One shellfish constable has taken this method a step further
by actually inducing spawning on his boat, mixing eggs and sperm, and releasing embryos
directly into the environment.
Remote Set Oysters
Annually about two million hatchery produced eyed larvae are remote set using methods
described by Jones and Jones, 1983. The eyed larvae are drained on to nitex netting, wrapped in
damp paper towel and refrigerated for at least 12 hours before introduction into the remote set
system. This treatment appears to expedite setting. The oysters are set on bags of oyster shell
cultch in aerated tanks with daily partial exchanges of sea water and daily feedings of cultured
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phytoplankton. After about 5 days, the shell bags are removed from the tanks and hung from a
float in the pond. After about a month, the bags are emptied and the spat covered shell planted
on the pond bottom.
Predator Control
As in any aquaculture venture, predation has been identified as a major obstical to the
success of the stock enhancement program. In response, the town shellfish constables have
initiated vigorous trapping programs for predatory crabs and starfish. The town of Edgartown
pays a bounty to fishermen for the crabs they remove from the shellfish beds.
Literature Cited
Adamkewicz, L. and M. Castagna, 1988. Genetics of shell color and pattern in the bay scallop
Argop^g" "radians. Journal of Heredity 79: 14-17.
Elek, 1,1985. Shell color polymorphism in the Atlantic bay scallop. Master's thesis. George
Mason University, Fairfax,Virginia, USA.
"i» . r: ' \ ' .. " ' ' .
Jones, G. and B. Jones, 1983. Methods for setting hatchery produced oyster larvae. B. C.
Ministry of Environment, Marine Resources Branch, Infor. Rep. No. 4.
Karney R. C., 1991. Ten years of scallop culture on Martha's Vineyard In An International
Compendium of Scallop Biology and Culture, Sandra E. Shumway, Editor. Published by the
World Aquaculture Society.
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Chapter3
Diagram of the Martha's Vir.eyard SheUfish Group Floating Sandbox Quahog Xurserv
4x8x22;styrdfoam Floats sandwiched between ^sheets of Plywood
XPolypropylene rope, looped through
sides of raft arid knotted at ends on
top of float
,72 Plywood bottom covered with 2'of
sand substrate
M.V.'SHELLFISH. GROUP - NURSERY RAFT
Figure
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Figure^
; Figured
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Quahog seed from floating sandbox nursery after one growing season
Figured
WO year old qualiogs from bottrom box nursery
Figure 5
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Cultured sscdllop seed Lri nurser-y case: a.r.d collecced in £i.s:i box prior uv
Figure 6
Figure 7
Figure 8
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CHAPTER 4
THE BAY SCALLOP RESTORATION PROJECT
IN THE WESTPORT RIVER
Turner, Wayne H., and Scott J. Scares, The Water Works Group,* Post Office Box 197
Westport Point, MA, 02791 USA. . .
Abstract
The time has come to reverse the trend of the deteriorating water quality in the Westport
River. To this end, it has become increasingly evident that a positive way to mitigate the effects
of pollution is to make it economically advantageous to do so. In an effort to focus public
attention on the problems facing communities like Westport, states like Massachusetts and
Rhode Island, and the economic well-being of the entire coast of the United States, The Water
Works Group has spawned the Bay Scallop Restoration Project.
This undertaking was launched in January of 1993 with the aim of increasing public
awareness about the plight and potential of the Westport River. By virtue of its economic value
and universal appeal, the bay scallop was selected as the vehicle through which resources could
be mobilized and public support and local commitment garnered. From its inception, the Project
has rallied an unprecedented outpouring of community and regional involvement centered
around the effort to return the bay scallop resource to the Westport River.
Faculty, graduate, and undergraduate students from the University of Rhode Island,
Massachusetts Institute of Technology, University of Massachusetts-Dartmouth, and Marine
Biological Laboratory at Woods Hole have been brought aboard to address technical aspects of
bay scallop propagation and pollution remediation. In support of these initiatives, local town
boards and agencies, including the Shellfish Department and the Board of Health, the
Massachusetts Division of Marine Fisheries, a substantial number of local businesses and
volunteers from the Westport Fishermen's Association, Westport River Watershed Alliance, and
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the general public as well as students and teachers from schools of five surrounding communities
have provided necessary building materials and equipment while investing more than 10,000
volunteer hours hi the effort during its first year.
The Water Works Group is a nonprofit organizanon working to restore, maintain, and
improve the economic, recreational, and aesthenc values oSwatersheds for the benefit of the
public: present andfuture.
Introduction
Historically, the Westport River (Figure 1) has supported a significant shellfishery for
bay scallops, Argopecten irradians (Figure 2); oysters, Crassostrea virginica; quahogs,
Mercenaria mercenaria; and soft shell clams, Mya arenaria, providing employment and
enjoyment for many residents of Westport (Town of Westport, Annual Reports 1949-1993). In
fact, the Massachusetts Division of Marine Fisheries, in 1968, recognized the Westport River as
one of the most productive commercial shellfishing areas on the south coast of Massachusetts
(Fiske et al, 1968> Since those prosperous days, Westport shellfish harvests have declined
siznificantlv and the town's commercial shellfish industry has suffered accordingly.
Figure J . jffisiarlc Bay Scallop JBtsatx of the Vfestport JR£v<:r
Though prodigious quantities of oysters, quahogs, and soft shell clams are still found
throughout the estuary, the largest percentages of these remain unharvestable as a consequence
of permanent and conditional shellfish closures. Westport saw its first shellfish closure in 1978
when the Massachusetts Depalllllent of Environmental Quality Engineering imposed a
temporary closure in a portion of the East Branch of the Westport River by virtue of bacterial
contamination. More extensive closures followed during the 1980s culminating in the closure of
1,300 acres of the West Branch and 1,776 acres of the East Branch by a combination of
permanent and conditional closures.
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In the years following 1978, the town of We%ort has made several efforts to identify the
sources of its closure-causing pollution. These in depth studies documented the nature and
origins of the bacterial pollution: stormwater run-off; obsolete septic systems; and agricultural
practices (Pivetz et al, 1986, Department of Health and Human Services Public Health Service,
FDA Shellfish Sanitation Branch, 1987; Hoagland et al, 1988; Metcalf et al, 1989). In spite of
the Town's best efforts over the past fifteen years, it has become increasingly evident that a
positive way to mitigate the effects of bacterial pollution is to make it economically
advantageous to do so. '
"»<«««-
Fixture 2. Estimated Scallop Harvest in the Westport River 1949-1993.
Discussion
In January .1993, under the auspices of Hie Westport Shellfish Department, theBay
Scallop Restoration Project, further referred to as the Project, was launched with the goal of
focusing public attention on the continuing decline'of water quality in the Westport River with
an eye toward reversing the trend. The bay scallop, by virtue of its economic value and universal
appeal, was selected as the vehicle through which resources could be mobilized.
The ability to harvest bay scallops, from waters deemed bacterially contaminated sets the
bay scallop apart from other shellfish species. This distinction arises because the marketable
portion of the bay scallop is the adductor muscle (the "eye"), whereas the marketable portion of
the other local shellfish species (oyster, quahog, soft-shell clam, and blue mussel) include the
viscera, where the water-borne pathogens associated with bacterial contamination accumulate.
Because of the risk to public health from the pathogens, these other shellfish have been declared
unfit for human consumption by the Division of Marine Fisheries. It was, however, this
distinction that allowed Westport scallopers in 1985, amidst shellfish closures, to harvest 66,000
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bushels of bay scallops with a value exceeding two million dollars (Town of Westport, Annual
Report, 1985).
According to historical data, the Westport River has supported a substantial commercial
bay scallop population (Town of Westport, Annual Reports, 1951-1985). However, as is the case
throughout the species range, extreme fluctuations in population raise a question regarding the
commercial dependability of the species. In an attempt to narrow the range over which bay
scallop populations fluctuate, various municipalities have initiated shellfish propagation
programs to manage their shellfish resources. These enhancement programs include the
broadcasting of hatchery reared and natural caught seed, bottom and hanging culture, as well as
the relocation of indigenous stocks (Kelly, 1981 and 1985; Manzi, 1988; Aoyama, 1989;
Grochowski, personal communication, 1993; Karney, personal communication 1993; Sherman,
personal communication, 1993).
In Westport, Massachusetts, oneSsuch endeavor, the Bay Scallop Restoration Project, has
aimed its. efforts at increasing the recruitment of bay scallop larvae and enhancing survival of
scallop seed to harvestable size and age. Recruitment and survival is enhanced through tile use of
simple and innovative equipment such as: spawning rafts; spat bags; and nursery rafts at various
stages throughout the life of the bay scallop. These methods serve to reduce mortality rates at the
most susceptible phases of the bay scallop's brief two year life.
With increased recruitment and improved survivability, Westport's bay scallop fishery
may once again flourish. The presence of a healthy bay scallop fishery would lend credence to
me economic significance of a clean and productive river. Furthermore, the presence of a
profitable bay scallop fishery may ignite interest in taking action to resolve the pollution
problems hindering the harvest of other shellfish species including the ever abundant yet long
unharvested oyster.
ih i
Methods
Increasing bay scallop larval recruitment suggests maximizing the success of the summer
spawn. To realize this, spawning scallops must first be in close enough proximity so as to engage
in mass spawning (Belding, 1910; Karney, personal communication, 1993). The importance of
this mass spawning event is the generation of a high, localized concentration of eggs and sperm
which increases the chance of fertilization. '
To encourage mass spawning, brood stock scallops were housed in wood framed rafts
covered with 1/4" hole extruded plastic mesh (Figure 3), built from donated materials by
students in the Westport High School wood shop class and other volunteers. Extensive scallop
dragging in both branches of the Westport River during the month of May 1993 (under the
direction of the Westport Shellfish Department and Massachusetts Division of Marine Fisheries)
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turned up 213 brood stock bay scallops in which to stock the rafts. To bolster this brood stock,
an additional 174 bay scallops were harvested in the waters of nearby Marion, MA (courtesy of
the Marion Shellfish/Harbor Master Department).
Figure 3. Spuaswrtirsg Raff.
These 387 brood stock bay scallops (ranging from nine to eighteen months old; 38.5%
first year scallops and 61.5% in their second year) were divided amongst three spawning rafts
and moored in three areas within the Westport River. Spawning sites were selected using
information about historic bay scallop beds in the Westport River and data collected by various
investigations of: the Massachusetts Division of Marine Fisheries; the Westport River Watershed
Alliance's Citizen's Monitoring Project; University of Massachusetts-Dartmouth; and the
Massachusetts State Climatologist; as well as the work of other Bay scallop researchers (Belding,
1910; Outsell, 1931; Marshall, 1960-61; Duggan, 1975; Tettelbach, et al, 1981). The data
discerned information regarding: annual precipitation; salinity; dissolved oxygen; turbidity; and
temperature for the Westport River and the watershed from which it originates during the past
two to forty years (depending on the parameter) and parameters conducive to bay scallop
growth.
With the warming waters of late spring and early summer, investigators on the Project
observed the ripening of the bay scallop gonad as it; increased in size, altered its shape, and
changed color from black to bright orange. The transformation of the gonad precedes the spawn
which is marked by the release of eggs and sperm when the water temperature rises to 20°C
-24°C (Belding, 1910; Sastry, 1963; Hardy, 1991). In addition to gonad observations, weekly
measurements of water temperature, salinity, and dissolved oxygen were collected at various
locations in the Westport River (data courtesy of the Westport River Watershed Alliance's
Citizen's Monitoring Project). Between April and September 1993 investigations of bay scallop
larval abundance/identification and food availability (seston analysis) were conducted by the
University of Rhode Island (data presently under analysis).
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With observations indicating the advent of the spawn, (i.e., gonad development, rise in
water temperature, appearance of larvae) the work of Belding (1910) and others have suggested
that larval settlement should occur within two to three weeks from the spawn. Typically, bay
"scallops set on eel grass, Zostera marina, however various studies have shown that bay scallop
larvae will attach to artificial substrate (Kelly, 1981 and 1985; Aoyama, 1989; Manzi, 1988;
Cputier, 1990). Accordingly, the Project utilized artificial substrate called spat bags (named for
the post larval, pre-seed scallops) to enhance the amount of available setting surface area. This
technique served to index settlement and post settlement recruitment in areas where the spat bags
were deployed.
Figure 4. Spat Rag Components and L&ngline Configuration.
With the assistance of numerous volunteers, 1,400 spat bags were constructed using
donated 50 pound capacity onion bags, used gillnet monofilament, polypropylene rope, and
small stones (for weight) (Figure 4). These spat bags were rigged with floats on 89 longlines,
28-35 meters in length, which were deployed and moored in nine historically significant scallop
harvesting areas (Figure 5). Lines were sequentially deployed over a six week period (the weeks
of June 6 and July 4 through August 1) which provided "fresh" substrate throughout the
spawning and settlement season. This deployment scheme also provided information indicating
which times and locations within the Westport River the best sets occurred for the 1993
spawning.
Within the last week of spat line deployment, periodic "spat checks" were added to the
testing regime and on August 17, 1993 the first spat was discovered (approximately 4mm in
height). As the weeks progressed spat checks revealed bay scallops in each area that spat bags
were positioned. Reports from local shellfishermen also confirmed the distribution of bay
scallop seed throughout the estuary (Earle, personal communication, 1993; Sherman, personal
communication, 1993).
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The rapidly approaching 1993/94 bay scalloping season, opening October 15, mandated
the retrieval of the 89 spat lines which were positioned above historically popular scalloping
beds. Accordingly, spat line collection began on the second week of September. Participation of
Westport and Dartmouth High Schools facilitated the laborious task of bringing in the lines and
the cataloging, recording, and subsequent analysis of all the scallops, the fouling organisms, and
volumes of other related information gleaned from each spat bag. This information was recorded
by the students on sheets that provided information for the quantitative and qualitative analysis
of each spat line. Additional analysis conducted by the University of Rhode Island (URI)
revealed the total yield to be 4,002 scallops ranging from 4-60mm in shell height with an overall
mean of 36.9 mm. The Ultl study also identified Cory's Island as the area displaying the greatest
recruitment (Tammi et al, 1994).
The bay scallop seed, collected in the spat bags and measured by the high school
students, was placed hi rafts identical to the rafts used to hold the brood stock scallops (Figure
4). These rafts, called nursery rafts attiuVstage, were moored in three areas selected so that
periodic observations made throughout the winter would not be inhibited by ice (Figure 5).
From the 4,002 scallops collected, 1,100 were transported to URI for over winter monitoring and
further studies on spawning and development Additionally, 12 liters of the seed (approximately
70 scallops/liter) were divided between two different raft types and placed in the three areas
shown in (Figure 5). URI is using these rafts: 1) to compare raft design; and 2) to determine
growth differences between scallops living on the bottom and scallops floating just below the
surface (report pending)
tgondr
. SB_
t [_in@s
= Spawning FZafts
Win-ter Ra-fts
S. Sttfffy
In rf*tr Wtzstftort:
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Conclusion
\ . '
A year's worth of work on the Project has shown that bay scallops will settle on artificial
eel grass ("spat bags"). More importantly, the methods employed by the Project serve to
demonstrate the potential of unified community action. In combating the problem of poor water
quality in Westport, the Project has produced a plan that encourages economic incentive, public
education, and hands-on community involvement all aimed at economically advantageous
pollution remediation.
With community involvement, enthusiasm, and energy at an unprecedented high, the
opportunity to capitalize on the public interest has presented itself. The awareness and attention
focused on the economic significance of the Westport River, shown by the presence of the
Project, has spurred interest in rejuvenating Westport's long dead oyster fishery which was
closed due to widespread bacterial pollution in 1978. To address the issue of Westport's bacterial
pollution problem, the Project has spawned two united undertakings: the Living Laboratory and
the One Watershed-at-a-Time Campaign.
Along the way, the three arms of the endeavor to reclaim the Westport River, have
captured the spirit, imagination, and involvement of a diverse congregation of people. These
people, to the tune of thousands of volunteer hours, have connected with some aspect of the
Project, whether it be on the bay scallop end, the education front, or the tributary watershed
effort The work being done hi the Westport River watershed represents a model for designing
economically advantageous ways to remedy non-point source pollution and holds boundless
opportunities for other communities suffering from similar problems.
References
Aoyama, S. 1989. The Mutsu Bay Scallop Fishery: Scallop Culture, Stock Enhancement and
Resource Management hi Marine Invertebrate Fisheries: Their Assessment and Management.
Ed. J. F. Caddy. John Wiley and Sons, NY.
Belding, D. L 1910. The Scallop Fishery of Massachusetts. Commonwealth of Massachusetts,
Division of Fish and Game. Marine Fisheries Section, Marine Fisheries Series Number 2.
!,'; | '. 'l||,;> , , ' "I ' | L i - .
Cqutier, C. 1990. Scallop Culture in Canada. World Aquaculture. 21(2): 54-62.
Department of Health and Human Services Public Health Service, Food and Drug
Administration, Shellfish Sanitation Branch, 1987. Sanitary Survey of the Westport River
Estuary, Westport, Massachusetts September-October, 1986. Northeast Technical Services,
North Kingston, RL
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NSA 1994 Proceedings Chapter 4
Duggan, W. P. 1975. Reactions of the Bay Scallop, Argopecten irradians, to Gradual Reduction
in Salinity. Ches. Sci. 16(4): 284-286.
Fiske, J. D., J. R. Curley, and R. P. Lawton, 1968. A Study of the Marine Resources of the
Westport River. Commonwealth of Massachusetts, Division of Marine Fisheries, Monograph
Series Number 7.
Outsell, J. S. 1931. Natural History of the Bay Scallop. Bull. U.S. Bur. Fish. 46: 569-632.
Hardy, D. 1991. Scallop Farming. Fishing News Books. Osney Mead, Oxford OX2 oEL,
England.
Hoagland, M. R, E. P. Kelly, D. W. Caldwell, and D. M. Fitzgerald, 1988. Hydrogeology and
Contamination Investigation of the West Branch of the Westport River Watershed.
Hydrogeology Research Group, Department of Geology. Boston University, Boston, MA.
Kelly, K. M. 1981. The Nantucket Bay Scallop Fishery: The Resource and its Management.
Shellfish and Marine Department, Nantucket, MA.
Kelly, K. M. 1985. An Update on the Management of the Nantucket Bay Scallop Resource.
Shellfish and Marine Department, Nantucket, MA.
Manzi, J. J. 1988. Scallop Culture on Hokkaido. World Aquaculture 20(1).
Marshall, N. 1960-61. Studies of the Niantic River, Connecticut, with special reference to the
Bay Scallop, Aquipecten irradians Limnology and Oceanography.
Mathiessen, G. C. 1992. Perspective on Shell Fisheries in Southern. New England. The Sounds
Conservancy, Lie. Essex, CT.
Metcalf and Eddy, Inc. 1989. Non point Source Management Plan for the Watershed of Snell
Creek, Westport, Massachusetts. Metcalf and Eddy, Inc., Wakefield, MA.
Pivetz, B. E., E. F. Kelley Jr., D. W. Caldwell, and D. M. Fitzgerald, 1986. Relationship
Between Suspended Sediment and the Movement of Bacteria in the East Branch of the Westport
River. Hydrogeology Research Group, Department of Geology, Boston University, Boston, MA.
Sastry, A, N. 1963. Reproduction of the Bay Scallop, Aquipecten irradians Lamarck, Influence
of Temperature on Maturation and Spawning. Biol. Bull. Mar. Bio. Lab., Woods Hole, MA.
Tammi, K. A., S. J. Scares, W.H. Turner, M. J. Rice 1994. Settlement and Recruitment of the
. . ' ; s -
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NSA 1994 Proceedings Chapter4
Bay Scallop, Argopecten irradians, to Artificial Spat Collectors in the Westport River Estuary,
Westport, MA. Abstracts, 14th Milford Aquaculture Seminar.
Tettelbach, S. T. and E.W. Rhodes 1981. Combined Effects of Temperature and Salinity on
Embryos and Larvae of the Northern Bay Scallop, Argopecten irradians irradians. Mar. Bio. 63,
249-256.
Personal Communications
Earle, Richard. Westport Massachuseffs Harbor Master. 2061 Main Road, Westport Point, MA.
Growchowski, Joe. Town Biologist, Nantucket Marine Laboratory. Nantucket, MA.
Kamey, Richard C. Martha's Vineyard Shellf sh Group Inc. Oak Bluffs, MA.
Mopk, Bill. Mook Sea Farms. Damariscotta, ME.
Sherman, Gary. WestportMassachuseffs Shellf sh Constable. Post Office Box 313 Westport
Point, MA.
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CHAPTERS
ENHANCING NEW YORK'S GREAT SOUTH BAY HARD CLAM
(MERCENARIA MERCENARIA) RESOURCE: DETERMINING
WHICH STRATEGY TO USE
Jeffrey Kassner
Town of Brookhayen
Division of Environmental Protection
3233 Rte 112
Medford, New York 11763 '
Abstract
Over the past two decades, spawner relays, sanctuaries, and transplants and seed hard clam
plantings have been undertaken in attempts to enhance the hard clam (Mercenaria mercenaria)
resource in New York's Great South Bay. Enhancement enjoys considerable popular support but
determining which strategy or strategies will yield the greatest return on investment is fraught
with uncertainties and difficulties: it must e assumed that the shellfish population is not at its
environmental carrying capacity and that the cause(s) can be corrected; the life history stage(s)
and environmental conditions) limiting hard clam abundance may not be known; the existing
management regime may be a contributing factor; and assessing the contribution of enhancement
strategies is technically difficult and expensive. The choice of strategy is critical because
whatever funds are expended on an enhancement strategy are no longer available for other
enhancement strategies or management options.
Introduction
Enhancing the abundance of commercially important molluscan shellfish stocks is a
historical and integral component of the management of many coastal shellfish resources.
Beginning the middle of the 19th century, for example, oystermen transplanted seed oysters to
growout beds and planted cultch to catch sets of oysters (Kochiss, 1974). In the early years of this
century, Belding (1909) concluded that one way to stop the decline of the quahaug [hard clam]
from the waters of Massachusetts was to seed the public waters and tidal flats with small shellfish.
With the development of shellfish mariculture technology over the past several decades, the use of
hatchery raised seed in the management of clam fisheries has been either suggested or tested in a
number of locations (Malouf, 1989). The concept of enhancing public shellfish resources in
coastal waters is generally viewed positively. Politically, measures to improve the supply of
shellfish have long enjoyed support because they are seen as an active solution rather than a
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passive response to the problem of low stock abundance (Kassner, 1988A). Shellfish harvesters
favor augmenting the natural abundance pf shellfish as an alternative to restricting harvest levels
(Bvassner, 1988B).There is thus a strong underlying predilection towards undertaking a resource
enhancement activity of some kind.
There are a variety of resource enhancement strategies that have at least a theoretical
potential to increase the abundance of shellfish in public waters. Determining which resource
enhancement strategy to use, however, is not an easy task but one of great importance because
funds spent to implement one strategy are not available to undertake another. In this paper, I will
first present a general background for enhancing public shellfish resources and then describe the
various projects being used to enhance the hard clam (Mercenaria mercenarid) resource of New
York's Great South" Bay.
Enhancing Shellfish Populations Theory
It must be recognized at the outset that the decision to undertake resource enhancement is
often motivated by falling shellfish abundance and landings and is thus driven by politics. As a
result, there is a prevailing sense of urgency which means that there is neither the time nor the
interest to undertake extensive studies or research as to the causes of the condition of the stock. It
also means that the enhancement must begin immediately.
' ' ' '*'!. - ., ' : ' ' ' ' ' ' '
The underlying assumption of shellfish resource enhancement is that a shellfish
population is not at its environmental carrying capacity and that if whatever conditions are
preventing the shellfish population from attaining its carrying capacity are eliminated or
counteracted, the size of the shellfish population will then increase to the carrying capacity.
Determining the carrying capacity and the conditions limiting shellfish abundance for a particular
shellfish population is not a simple technical task and one that is made more difficult because
both the carrying capacity and the limiting condition probably vary both temporally and spatially.
The necessary studies are also likely to be costly and time consuming.
An additional complication in undertaking shellfish resource enhancement stems from the
fact that shellfish populations fluctuate from year to year (Caddy, 1989). The implication is that
the strength of the condition limiting abundance varies as well which could, in turn, mean that
enhancement will succeed in adding individuals to a shellfish population only when conditions
are favorable for the existing population to produce recruits and that enhancement will make a
minimal contribution when conditions re not favorable for .the existing population to produce
recruits. Thus, resource enhancement rather than increasing abundance when population size is
depressed and therefore most needed, may only succeed when production is naturally high and
not as needed.
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For convenience, the conditions limiting the* size of a shellfish population can be divided
into life history based, environmental based, ,and management based. For shellfish, the life history
based conditions can be further subdivided into three stages: (1) larval supply including
gametogenesis and fertilization; (2) settlement success together with initial post-settlement growth
and survival; and, (3) juvenile growth and survival. Environmental based conditions that may be
limiting population size include deterioration of water quality, habitat loss or alteration, and
unusual biological or climatic events. Management based conditions include the harvest of
undersized shellfish and overfishing. Assuming that management is not a limiting condition or
can be addressed independently, if a resource enhancement strategy is to increase shellfish
abundance, it must therefore either bypass the limiting life history stage or mitigate the limiting
environmental condition.
Unfortunately, the limiting life history stage or limiting environmental condition at a
particular time and location is often not known and may not be easily identified within the time
frame available. The choice of enhancement strategy must therefore often rely upon the best
available information from limited field data as well as the scientific literature. For each of the
life history stages and environmental conditions that may be limiting population abundance, there
are number of alternative resource enhancement strategies that could be implemented. For each
strategy, however, there are numerous technical and theoretical reasons why it should and
shouldn't succeed in increasing the abundance of shellfish. The different enhancement strategies
also vary with respect to cost, length of time required to achieve results, and ease of
implementation. Acceptability to shellfish harvesters may also be a significant factor as shell
fishermen are often politically active and can use this to block the implementation of an
enhancement strategy that they do not support.
The Practice, The Location
The Great South Bay is the largest in a chain of bays created by a series of barrier islands
that extend nearly the entire length of the south shore of Long Island, New York The bay is 50
km long, varies in width from 2.5 to 8.0 km and has an area of approximately .16 million hectares
,(Kassner,1988B). During the 19th century, the Great South Bay was a major
producer of the east coast oyster (Crassostrea virginica) and was world famous for its "Blue Point"
oyster (Mattiessen, 1992). The oyster fishery began to decline shortly after the turn of century
due to a variety of social and economic actors as well as a shift in the bay's ecology that greatly
reduced the abundance of oysters. The abundance of hard clams rose, however, and a fishery for
hard clams replaced the oyster fishery. Over the past half century, the hard clam fishery has
undergone two periods of expansion and contraction (Kassner, 1988B) Following a peak in hard
clam production in the mid 1940s, hard clam abundance and landings fell through the early 1950s.
Beginning in the early 1960s, hard clam abundance and landings rose, reaching a peak of over
600,000 bushels in the early 1970s. After 1976, abundance and landings fell dramatically.
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The distribution and abundance of the hard clam is weather, bottom type, harvesting
effort, and predator abundance (Stanley and DeWitt, 1983). In the Great South Bay, hard clams
are widely distributed with distinct and stable areas of high and low hard clam abundance
(Kassner, Cerrato, and Carrano, 1991). Hard clam abundance also varies from year-to-year and
appears to be limited by either a low level of hard clam setting or poor survival to age 1.
The Strategies
Four strategies have recently been or are now being used to enhance the public hard clam
resource in the Great South Bay: spawner relays, spawner transplants, spawner sanctuaries, and
the planting of hatchery raised seed hard clams. The first three strategies address abundance
limiting conditions due to problems with larval supply and the fourth strategy addresses
abundance limiting conditions due to problems with post settlement survival.
Spawner relays entail increasing the abundance of spawning individuals by transplanting
adult hard clams from other coastal waters into the Great South Bay. It is an appropriate
enhancement strategy when there is an inadquate supply of larvae or when the proximity of
breeding individuals to each other is too great to ensure fertilization success. Spawner relays are a
traditional enhancement strategy that enjoy the support of the shell fishermen.
Typically, several hundred bushels (approximately 150 large, chowder size hard clams)
of "spawners" are purchased at a cost of $15 to $20 per bushel for planting in the Great South Bay
in the spring and early summer. The spawners are typically spread out in several areas of the bay
from slow moving boats. A spawner sanctuary is defined as a site that is stocked with large,
fecund adult hard clams and located such that the setting of larvae from the site will be maximized
in a previously selected area which has been identified as good-hard clam habitat It is an
appropriate enhancement strategy when breeding subpopulations are positioned so that hard clam
larvae are not being transported to desired areas.
Fortunately, computer modeling of the circulation in the Great South Bay was done in the
1980s and has provided guidance in the selection of spawner sanctuary locations (Carter, Wong,
and Malouf, 1984). The use of spawner sanctuaries has been gaining increased acceptance over
the past several years. To increase larval production, adult hard clams are initially transplanted
into a sanctuary and to protect the spawning population, harvesting within a spawner sanctuary
may be prohibited. One advantage of a spawner sanctuary is that once established, it should
continue to supply hard clam larvae indefinitely. A major problem with the implementation of
spawner sanctuaries is the high abundance of shellfish which is attractive to poachers so that the
success of a spawner sanctuary may depend highly upon enforcement.
Determining the contribution of spawner relays and spawner sanctuaries to the hard clam
population is very difficult Monitoring spawning and tracking larval abundance and distribution
is time consuming and methods for differentiating the larvae of the natural population from the
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those arising from the relay or sanctuary are not readily available. It is also probable that spawner
relays and spawner sanctuaries are not successful every year and must therefore be viewed as
long-term enhancement strategies.
Spawner transplants are a variation of the spawner relays. This strategy involves
harvesting adult clams during early spring from waters cooler than the Great South Bay and then
transplanting them into the expectation that they will spawn, because of their presumed delayed
gametogensis (Loosanoff, 1937), after the native hard clam population has spawned. The rational
is that reproductive success is dependent upon the chance co-occurrence of hard clam larvae and
suitable environmental conditions so that the longer larvae are present in the bay, the greater the
chances at least some will encounter favorable conditions for survival and setting. Timing is
therefore critical but problematical (Kassner and Malouf, 1982). Although highly popular with
shell fishermen, spawner transplants are no longer undertaken primarily because of difficulties in
obtaining bloodstock.
The planting of hatchery produced seed hard clams having shell lengths of 5 to 25 mm
has been practiced in the Great South Bay since the late 1970s and several million seed hard
clams are currently being planted annually. The planting of seed hard clams is the appropriate
enhancement strategy if larvae are reaching an area but are not setting or do not have high
survival to some minimum size. Seed clams thus bypass the larval period and initial high
mortality sizes. This strategy is relatively popular among most baymen and elected officials
because it is tangible, offers increased control and lets the shellfish be placed into a particular
area. The survival rate of seed hard clams planted to increase natural production is, however,
largely uncertain. Survival is likely to increase with increasing seed size but because the cost per
seed hard clam increases with seed size, there is a tradeoff between number of seed planted and -
the expected return. At its present scale, seed planting does not contribute a significant number of
hard clams; to the total harvest, although it does increase abundance in discrete areas.
Discussion
While enhancement offers the potential of increased abundance, the cost-effectiveness of
the various resource enhancement strategies to increase stock size is not known. It is difficult to
differentiate natural production and natural population fluctuations from production arising from
enhancement activities and for various technical reasons, tracking the subsequent survival and
contribution to the shellfish population has proven to be very difficult In addition, trying to
assess the contribution of an enhancement project can be costly and enjoys little support because
the money spent on evaluation is not available for enhancement. Small pilot projects may not
yield the type of information needed because scale may be influence the results. There has been
relatively little attention given to mitigating environmental conditions that may be limiting the
abundance of hard clams in the Great South Bay. .This may be, in part, because the benefits of
environmental based strategies do not seem as tangible as putting more hard clams into the bay,
either as bloodstock or seed hard clams. It is also probably reflects a lack of knowledge as to what
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conditions are causing low hard clam abundance (or are conducive to high abundance) and the
inability to mitigate many of the environmental conditions that can limit abundance.
Increasing the amount of favorable hard clam habitat in the Great South Bay is one
environmental enhancement strategy that may hold considerable long term potential. Hard clam
abundance in the Great South Bay has been found to be generally higher in course sediments
containing shell and many areas of high hard clam abundance are associated with relic oyster
reels (Kassner, Cerrato, and Carrano, 1991). The planting of shell to create to this type of habitat
could increase the amount of productive bay bottom. A pilot scale planting using surf clam
(Spisula solidissima) shells was undertaken in 1989 (Kassner, Cerrato, and Carrano, 1991) but the
project has been subsequently deemed unsuccessful because the volume of shell used was too
small and it was placed on a muddy bottom where it sank into the sediment.
One aspect of shellfish resource enhancement that is often neglected is the matter of
scale. The logistics and expense of producing enough hard clams to significantly increase
production is considerable. The problem is that according to McHugh (1981), enhancement tends
to consider that "millions are sufficient when billions may be required". Population enhancement
can be an important component of a shellfish management program, although enhancement
should not be seen as a justification not to limit harvesting or institute other regulatory controls.
The absence of scientific certainty should not preclude trying to enhance population abundance
such that the only realistic option may be to simply do what makes sense and to then hope for the
best-
Acknowledgements
The continuing support of Brookhaven Town Supervisor John LaMura and members of
the Brookhaven Town Board for improving the shellfish resources of the Town of Brookhaven
is recognized and appreciated. The commercial shellfish harvesters have provided many hours of
stimulating discussion and considerable assistance and are the reason why shellfish resources
must be enhanced whenever possible.
References
Belding, D. L. 19iO. A.report upon the quahaug and oyster fisheries of Massachusetts.
Contribution No. 12, Massachusetts Division of Marine Fisheries, Department of Natural
Resources, Boston, Massachusetts. 127pp.
Caddy, J. F. 1989. Recent developments in research and management for wild stocks of bivalves
and gastropods. Pages 665 - 724 in J. F. Caddy ed. Marine Invertebrate Fisheries: Their
Assessment And Management. John Wiley & Sons, New York.
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Carter, H.H., K-C Wong, and RE. Malouf 1984. Maximizing hard clam sets at specified
locations in Great South Bay by means of a larval dispersion model. Marine Science
Research Center, State University of New York at Stony Brook, Special Report 54, Reference
84-1. 66pp.
Kassner, J. 1988 A. The baymen of the Great South Bay, New York: a preliminary ecological
profile. MAST 1(2): 182-195.
Kassner, J. 1988B. The consequence of baymen: the hard clam (Mercenaria mercenaria Linne')
management situation in Great South Bay, New York. J. Shellf, Res. 7(2):289-293.
Kassner, J., R. Cerrato, and T. Carrano. 1991. Towards understanding and improving the
abundance of quahogs (Mercenaria mercenaria) in the eastern Great South Bay, N. Y. Pages 69-
78. in M. A. Rice, M. Grady and M. L. Schwartz eds. Rhode Island Sea Grant publication
P1235.
Kassner, J. and R E. Malouf. 1982. An evaluation of "spawner transplants" as a management tool
in Long Island's hard clam fishery. J. Shellf. Res. 2(2) 165-172.
Kochiss, J. M. 1974. Oystering from New York to Boston. Wesleyan University Press,
Middletown, Connecticut 251 pp.
Loosanoff, V. L. 1937. Seasonal gonadal changes in adultclams Venus mercenaria (L.). Biol
Bull.72(3):406-416.
Malouf, R E. 1989. Clam culture as a resource management tool. Pages 427 - 449. in J. J. Manzi
and M Castagna eds. Clam mariculture in North America. Elsevier, New York.
Matthiessen, G. C. 1992. Perspective on shellfisheries in southern New England. The Sounds
Conservancy, Inc. Essex, Connecticut. 56pp.
McHugh, J.L. 1981. Recent advance in hard clam mariculture. J. Shellf. Res. 1(1): 51 - 55.
Stanley,!. G., and RDeWitt. 1983. Species profiles: life histories and environmental
requirements of coast fishes and invertebrates (North Atlantic) ~ hard clam. U.S. Fish and Wildl.
Serv. FWS/OBS-82/11.18. U.S. Army Corps of Engineers, TREL-82-4. 19pp.
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CHAPTER 6
SHELLFISH ENHANCEMENT PROGRAMS: ARE THEY
ENOUGH TO MAINTAIN A FISHERY RESOURCE?
Sandra L. Macfarlane
Town of Orleans Conservation
Department
Orleans, Ma. 02653-3699
l!' , V ' , , - ,
Introduction
The landmass of Cape Cod, Massachusetts resembles an arm when viewed frona a
satellite image. But this peninsula is not much more than a large sandbar sticking out into the
Atlantic. And like a sandbar, it is a fragile piece of land that is part of a geologic evolutionary
cfaain qf events with a finite lifespan. The people who live there as residents and those who visit
as tourists enjoy the multitude of natural resources that Cape Cod offers, but protecting those
resources tomorrow is an increasingly difficult challenge for the 15 towns that delineate the
municipal boundaries of Cape Cod.
Shellfishing has been an important activity, both economically and culturally, for
hundreds of years as indicated by the number and location of shell middens found along our
cdasts, but it is mostly within the last century that shellfish resources have been "managed".
Shellfish management in the Town of Orleans, a small community located in the "elbow" of
Cape Cod, takes place primarily at the local level where each individual town controls its own
shellfish resources under broad guidelines by the state. Size limits of shellfish, duties of shellfish
officers, and contaminated shellfish are all regulated by the state hut harvesting areas, catch
limits, methods, and licenses are all managed on the local level1.
The Town of Orleans (it may be referred to as Orleans in this document) is fortunate to
have three separate estuaries within its jurisdictional boundary: Cape Cod Bay, Pleasant Bay and
Hauset/Town Cove. Each of the embayments are very productive estuaries,) that provide habitat
for four major species of commercially important shellfish: soft shell clams (Mya arenaria). hard
clams or quahaugs (Mercenaria mercenaria). mussels (Mytilus edulis^ and bay scallops
(Argopecten irradians irradians).
Roman, C.T. and K.W. Able ct. al. 1989.
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Figure 1
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ORLEANS
Figure 2
(Jiike tit' Water
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Town., of. Or I e a n s E m b a y m e n t s
Figure 3
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Most of the shellfish harvest statistics have shown a decline over the years with the
exception of scallops that show typical peaks and valleys of abundance. Although over-fishing
is a problem and may be one of the causes of decline, other factors such as land use patterns over
the last twenty years, and their effect on shellfish resources and habitat may play a more
important role. Attempts to counteract the decline in abundance of shellfish involve various
management tools including, but not limited to, enhancement programs.
Management Options
" ' , |JV! ' ' ' " ' . ' , : '
Enhancement projects have been conducted by the town for all species of shellfish over
the years but the primary programs have concentrated on clams and quahaugs. Propagation
techniques included re-seeding programs using hatchery reared seed, transplants of seed shellfish
from abundant areas to less prolific areas, and transplants, of spawner stocks to the natural
environment.
In addition to enhancement or propagation projects, the primary tools used for shellfish
management in Orleans have been seasonal opening or closing of specific areas to allow for
either harvest or natural re-seeding (harvest area rotations), catch limits, gear restrictions and
enforcement of established regulations.
Commercial and recreational permit holders may fish in any open area, but commercial
harvesters are prohibited from fishing in areas reserved for recreational permit holders in
accordance with state mandate. Areas may also be restricted according to the season of the year
or by harvest methods. Some are open during the summer setting (and tourist) season while
others are closed during that time to allow for natural propagation.
Established harvest limits are dependent on the type of permit issued and may change
according to abundance. Generally, recreational permit holders are allowed 1 ten quart bucket of
clams or quahaugs per week, 0.5 bushel of mussels per week and 1 bushel of scallops per day
during scallop season (October 1-April 30). Scallops are the most valuable species of shellfish
within the town, and when abundance is high, the economic boon to the local economy is
substantial.
Soft Shell Clam Projects
Orleans has experimented with transplanting seed clams (Mya arenana) from Lonnie's.
River in the Pleasant Bay system to Town Cove and Cape Cod Bay fiats with excellent results.
For several years, 1977-1980, a portion of Lonnie's River yielded seed clams in excess of
400/square foot (1/3 square meter). When the clams were approximately 0.5 -1 inch (15-25mm),
the town transplanted some of them to less productive areas. The clams were harvested from the
river by using a pump to loosen the substrate in which they had become embedded. The clams
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and sand were then vacuumed into a hardware clottfbasket where the sand was pumped through
the mesh and the clean clams were captured. Damage to the clams was minimal using this
method. The clams were transferred to onion bags and usually held overnight in the water.
On the following day, the intertidal flats scheduled to receive the seed clams were
narrowed with a mechanized plow. The clams were broadcast in the loosened furrows on an
incoming tide. The majority of clams burrowed in quickly (within an hour) and transplant
mortality, usually caused by avian predation, was limited to damaged clams. By the next season
those clams that survived the initial transplant and the following winter had become both
sexually mature and of legal size for harvesting. - . -
The Cape Cod Bay flats, which extend approximately 1.5 miles from shore are
considered to be a hostile environment for shellfish because of wind and wave action in the 9-
foot tidal range and ice scour in the winter. The town conducted experiments on these intertidal
flats where netting was added to the experimental plots the following year after transplant to
contain the clains. The clams had attained sexual maturity and the town attempted to produce a
new set of seed clams in the same area from these adult clams. Wooden frames covered with
netting were placed over the transplanted clams in late spring. The transplanted clams produced
a new set of seed. Covering large areas with netting was prohibitively expensive; yet without the
netting; successful .setting of new seed clams was inefficient, therefore, the town opted to
transplant clams to areas where natural production gained from the, transplant was more assured
instead of continuing with a "put and take" approach.
Quahaugs
The major propagation program from 1975-1989 utilized by the Town of Orleans was the
nursery culture of hatchery-reared quahaugs rMercenaria mercenari^ Orleans used bottom and
raft cultures; (?) extensively utilizing the natural environment for both methods. In addition, the
town transplanted thousands of bushels of spawner-size quahaugs from the deep waters of Cape
Cod Bay to the Town Cove and Pleasant Bay. Orleans also developed a small hatchery using
pumped seawater which evolved into an upweller facility.
The program began with bottom cultures in which hatchery-raised seed was embedded in
plots that were covered with netting attached to wooden frames (3 feet X 6 feet) at 10
experimental sites throughout the estuaries. The success in the first year, based mostly on
survival, led to an expansion of the program. The contained areas, outlined by the wooden
frames, were increased (6 feet X 10 feet) and embedded with more seed. These larger boxes were
dug into the substrate at locations that had shown promise the previous year. Since the winter of
1976-77 was more harsh than the previous winter, the survival of the seed was substantially less
than the previous year. . .
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Based on a design by George Souza, shellfish constable of the neighboring Falmouth, the
town constructed floating sand-filled rafts in 1976. The rafts were set a float in two protected
ponds, one in the Pleasant Bay area (Lonnie's Pond) and one in the Nauset system (Mill Pond).
The rafts proved very successful with very little mortality and excellent growth. As a bonus, the
seed was large enough by the end of the growing season to be transplanted to the wild without
having to worry about over wintering. However, a planting density of about 500 per sq. ft.
inhibited the expansion of the program further because of the number of rafts that would be
required and the labor necessary to manage the rafts.
When waterfront property became available, a small (16 feet X 24 feet) building was
moved to a site on Town Cove where a small low-tech, low-cost hatchery was established. The
rafts were used while the hatchery was being developed. The hatchery used plastic trash cans for
larval tanks and free plastic buckets for sieves; typical hatchery algal species (T-Isochrisis,
lylonochrisis, and Dunaliella) were grown on site to feed the larvae and juveniles. Spawning
stock was harvested from different areas in town and spawning took place in June and July using
me animal's natural spawning time.
The hatchery was successful in spawning quahogs but using the animal's natural rhythm
and spawning them in the summer did not allow enough time for them to grow to a size where
they would survive the winter and therefore the seed had to be over wintered, which proved to be
a difficult task. Fortunately, while methodologies for over wintering seed were being developed,
the upweller technology became available.
The building was modified as an upweller facility rather than a hatchery by adding tanks
and silos. Upwellers are designed with a container (silo) of seed inserted in a tank with flowing
seawater. Water flows into the tank, up through netting on the bottom of the silo and exits the
silo from an outfall pipe near its top. The flow of water allows some fecal particles to be washed
away but daily cleaning of the silos is generally required especially when the seed is very small.
The silos were made of free 5-gallon plastic buckets with tight fitting lids that contain holes and
netting. If the volume of water being pumped is sufficient, each silo can handle tens of thousands
of seed. As the seed grew, they were thinned and transferred to more silos.. At the completion of
this process, 1.0 million seed were raised from 1.0 mm. to 12-15mm in 46 silos. Growth
appeared to be directionally proportional to the density, volume of water and the number of silos
available.
Algae, the animals' daily source of food, was grown on site. It was observed that
quahogs generally stop feeding in late July and early August because of the high water
temperature, lack of oxygen, and the type of phytoplankton in the water. This phytoplankton was
predominantly dinoflagellates. To overcome this, the water was aerated; the animals were given
a dose of food and their environment was kept clean. These techniques were apparently
successful. During the four year period, between 1986 and 1989, 1 million seed was raised per
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year, with a greater than 95% survival jpi-ior to transplant ,
- By utilizing upwellers, the facility was operated only in the summer; therefore it was not
necessary to expend funds on heating seawater during the winter which would have been
necessary to condition and spawn quahogs in the hatchery. From 1975-1989,. the Town of
Orleans raised approximately 6 million seed quahogs which were transplanted throughout the
estuaries bordering the town. To prevent predation during transplant, the seed was transplanted in
November when the water temperature had cooled to approximately 8-10° C. It was observed
that transplanting earlier, in September or October, especially if the seed was less than 1 inch, was
futile because of predation, primarily from baitfish which ate either the foot or siphon of the
seed. It was also noted that quahogs stop feeding entirely when the water temperature falls to 38°
F and start feeding again at 42° F. By planting them at around 45° F, the seed had enough energy
to burrow and their predators had slowed their own feeding activity; thereby creating a favorable
environment for the seed to survive the initial transplant and generally the winter as well. The
land-based facility was abandoned in 1990 in favor of lower cost (less labor and no seawater
system to maintain) bottom boxes and floating trays. Orleans currently raises 300.000 seed per
year. ' ' ,
Although the propagation program was successful, the impact of pollution became a
concern. Meetinghouse Pond in Pleasant Bay was closed to harvest by the Mass, Division of
Marine Fisheries because of higher than acceptable levels of fecal coliform bacteria (14/1OO
ml.). In 1988 and 1989, large areas of the estuaries bordering Orleans were being closed. At one
point, the entire Nauset estuary, the marsh creeks on Cape Cod Bay (5), and several ponds in '
Pleasant Bay were closed. All of the areas closed were productive habitat for shellfish with the
exception of the upper marsh creeks on Cape Cod Bay.
..[See Figures 4- 7 for shellfish harvest information.]
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5COOOO
<
Figure 5
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HARVEST OF BAY SCALLOPS IN ORLEANS
Figure 6
8000CO
700000 f
HARVEST OF MUSSELS IN ORLEANS
YEAR
Figure 7
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Demographics
Orleans was considered a rural fishing/farming community until the middle of this
century but the economy has shifted more toward tourism. As a tourist area, Orleans- located
adjacent to the Cape Cod National Seashore is known for its sandy beaches and as a haven for
water-dependent activities such as boating and fishing. It is accessible to millions of people who
live within a day's drive and because of its location at the confluence of three major roads.
Routes 6, 6 A and 28, it is the business hub of the Lower Cape. Visitors, especially retirees.
stayed and made Orleans their home. A building boom in the 70's and 80's2 took place to
accommodate the influx of new residents who were attracted to the town (Figure 8).
2CCOQ
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Figure 8
2Cape Cod Marine Quality Task Force, 1988.
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HARVEST Or GUAHAUGS IN RELATION
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Figure 9
The population in Orleans in 1970 was 2700; by 1988 it had increased to 6000 permanent
residents. Although the population triples during the summer tourist season3, it was estimated
that in 1980 sixty-nine percent of .all homes in the town were occupied year round (or at least one
half of the year4.
The development of single family homes on 40,000 square feet of land per lot has '
resulted in the construction of 2378 new housing units from 1970 to 19905. Individual septic
systems are the method of waste removal and although they are efficient at removing bacteria,
they are inefficient'at removing nutrients, especially nitrogen compounds, that can cause nutrient
enrichment in the estuaries. However, this development also resulted in an increase in
impervious surfaces, especially roads. Storm water runoff from impervious surfaces has been
documented as a source of nonpoint pollution including bacteria, nutrients and toxic chemicals.
These pollutants have been implicated in water quality degradation. Therefore, the impact of
pollution from development, specifically nonpoint source pollution, is a growing concern.
3 Marilyn Fifield, Statistics Office, Gape cod Commission, personal communication
4 Town of Orleans, 1994.
5 ibid ; / "' ''-
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Shellfish harvest is directly related to abundance and effort, and effort is directly related
to economic factors such as price and abundance of off-shore fin and lobster fisheries and/or the
availability of shore side construction related jobs6. Abundance, however, may be related to such
factors of as over-fishing; however, it could also be associated with the effects of land use
patterns hi the watershed of the estuary (Figure 9). These factors may play a more important
role than harvesting. Since 1980, most species have shown a decline in harvest. Scallops, which
are notorious for peaks and valleys of abundance 7,8,9, have been abundant sporadically but high
quantity is generally the exception, not the rule. Because of the economic factors, harvest
statistics do not necessarily reflect the amount of stock present; they can indicate the condition of
the stock but they can also indicate problems within the embayments.
In 1974, most of the Nauset estuary was closed to shellfishing because of "red tide" or
paralytic shellfish poisoning found primarily in two semi-enclosed ponds within the estuary. The
"red tide" are algal blooms consisting of motile cells in ideal conditions and produce resting
cysts during unfavorable conditions. These cysts often bloom again into a planktonic stage when
conditions are favorable. The Environmental Protection Agency ocean survey vessel, the Peter
W. Anderson10 while monitoring conditions in Orleans, found a correlation'between
temperature, salinity and possibly nutrient levels as triggers for an algal bloom.
In 1982, Meetinghouse Pond (Pleasant Bay) was closed to shellfishing by the State
because of fecal coliform levels that exceeded the established limit (Figure 10). In 1988,
portions of the Pleasant Bay estuary were closed as were the marsh creeks on Cape Cod Bay and
the entire Nauset/Town Cove estuary was again closed during the summer and in 1989, and
portions of the Nauset system have been closed for extensive periods of tune. Since fecal,
coliform bacteria originates from warm blooded animals, including but not limited to humans,
finding the source of contamination became an important aspect of shellfish management.
6 Macfarlane, S.L., personal observation
1, ' . it' .'
7 Belding, D.L. 1910.
8 Macfarlane, S.L., 1991.
9 Capuzzo, J.M and R.E. Taylor, Jr. 1980
10 Anderson, D.M., 1979
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MEETINGHOUSE POND DRAIN
Figure 10
It has been determined that land use practices may seriously impact both the
quantity of stock present in the bays through habitat degradation and the harvest readiness of the
stock due to fecal coliform contamination. While the Town of Orleans has used available
management tools as well as stock enhancement programs, past experience has led to the
conclusion that the mitigation of some of the effects of land uses is critical for the continued
production of harvestable shellfish from uncontaminated estuaries.
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Issue Identification
',"' " i " ' . ,!l ,"'',"'" * ' , , . ,- '
As a result of the shellfish closures in Orleans, the town formed a Water Quality Task
Force in 1987 to identify some of the problem areas and recommend solutions. The Task Force
recognized that some areas needed to be cleaned up whereas other areas needed to be protected in
ojrder to maintain high water quality. Water quality problems were divided into several broad
categories:
l.Stormwater runoff ,
2 Nutrient enrichment/eutrophication
3.Effects of private docks and piers , . ' .
4. Erosion
Stormwater Runoff
The Water Quality Task Force identified and mapped all the existing surface drainage
systems within the town. Also, a water quality monitoring laboratory was developed to test for
fecal coliform bacteria using the membrane filtration technique. Orleans collected water samples
from pipes, roads and estuaries. Using the results obtained from the testing, the task force
prioritized the drainage systems and recommended remedial measures for the worst drains
according to resources affected.
.,..,. j . '
Meetinghouse Pond had been closed since 1982 and since over $ 100,'000 worth of clams
had been harvested from the pond in 1987, and two separate road drains were identified as the
primary cause of the contamination, remediation projects for those drains were a top priority
(Figures 11 and 12). In addition, two drains collected most of the drainage from the downtown
business district and another collected water from the state road and a private corporation. These
five drams (see map) became the focus of a drainage remediation program. Over $400,000 was
appropriated by the town for initial study of the problem, for final plans and for construction. In
addition, the Friends of Meetinghouse Pond, a neighborhood association, donated funds for
initial engineering for one of the drains in Meetinghouse Pond (Barley Neck Road site), the state
highway drains were retrofitted with leaching catch basins that were installed during a re-
surfacing project and a private corporation constructed an innovative filter dam system on their
property.
Each drainage system was mapped and the contributing area and amount of stormwater
was calculated14. Each remediation method was sized to handle the first 1 inch (2.5 cm) of
rainfall, known as the "first flush" which is the amount of water most likely to contain the
majority of contaminants, including bacteria, sediments, nutrients and toxics. In all but one case,
infiltration leaching chambers were judged to be the best method of treatment. In each area, a
gross particle separator, (a tank with baffles that allows sediment to be deposited in the bottom of
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the tank and floating hydrocarbons are trapped witriin the baffled area) was installed prior to the
leaching galleys, to accumulate sediments-and floating hydrocarbons. Diversion manholes were
constructed to divert water to the leaching galleys but to also allow for heavy rain storms to flow
freely to the estuaries after the leaching galleys were filled. The leaching galleys were laroe
concrete structures, surrounded by stone, where stormwafer could filter through the oravel and
percolate to the grouhdwater where it would enter the estuary in a more diffuse manner. -'
The Barley Neck Road drain was completed in 1992 and construction of the other drains
was completed by May, 1993. A new water quality laboratory was established jointly with
Eastham, a neighboring town. Volunteers were trained in laboratory techniques so that the
systems could be monitored in a cost-effective manner. Lack of rainfall during the summer of
199, precluded the monitoring efforts but the results from one test site, Meetinghouse Pond at
Mam & Beach exhibited a dramatic-decrease after May, 1993 when the new system was
installed Even with high water temperature, when bacteria counts have traditionally been in the-
range of 100,000, either no water was seen coming from the pipe or the bacteria had been
effectively removed from the water. These preliminary results have shown that the shellfish
growing area was not receiving additional fecal coliform bacteria.
The Barley Neck Road, Beach Road, and Academy Place sites have all been successful
Academy Place is especially effective. Only in storm events much greater than 1 inch (2 5 cm)'
has there been any water observed coming from the pipe. This is gratifying because of the
potential for very serious contamination due to the proximity of this drain to the business district
Water sampling will continue so that we can monitor the effectiveness of these systems over time
and judge the amount of maintenance they will need in order to remain effective. In addition the
results of the sampling effort has been forwarded to the Mass. Division of Marine Fisheries so
that they can re-sample the closed areas and hopefully open them to shellfishing. In addition to
the major pipes, minor drains have been prioritized for remediation. Some of these include roads
that have asphalt beams constructed along the side of the road to channel the water off the road
but which also serve as a conduit for accumulated stormwater. Many of these roads typically end
in launching ramps for boats which means that the stormwater has an unobstructed entrancewav
to the embayment. These systems wMl^be addressed in order of priority when funds are available
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r I e a n s S. tm r m w a t e r Drainage
R feiri eci i ation Sites
(J
Figure 11
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Chapter 6
Figure 12
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Nutrient Enrichment/Eutrophication
. , ,.>i,"> / ' < ' ,. . : ' , .'»
Nutrients enter the estuaries through natural pathways and through land'use practices ('').
On-site septic systems are the major source of nitrogen from the land, followed by fertilizers, and
storm-water. Although a natural component of the estuary., excessive amounts of nutrients can
lead to microscopic and macroscopic algal blooms, anoxic conditions, fish kills and sediment
changes that result in a loss of shellfish habitat.
Prior to 1987, scattered areas throughout Orleans exhibited, effects of nutrient enrichment.
Eelgrass in the expanse of Little Pleasant Bay were covered with epiphytic growth and
"companion" seaweeds such as Calithamnion sp. Some poorly flushed areas contained pockets of
concentrated macrophytic growth and moriospecific blooms of phytoplankton (primarily
dinoflagellates) were fairly common especially in the upper reaches of Pleasant Bay. Changes in
sediment from hard bottom to silty, heavy organic mud were observed in several locations that
had previously been clam habitat. Areas of obvious groundwater seeps were very likely to have
profuse amounts of sea lettuce (Ulva lactuca) and/or Enteromorpha sp. by the end of the summer.
Since groundwater moves relatively slowly through the ground12 the Task Force recognized that
the effects of the building boom would not be observed in the estuary until some time in the
future and became concerned as to what steps may he taken to lessen the impact.
In 1987, Orleans received a reprieve of sorts from advancing eutrophication because of a
breech hi the barrier beach that protects Pleasant Bay. The new inlet, formed in January, 1987,
created a set of hydrodynamic circumstances that have changed the flushing characteristics of the
bay entirely. The Orleans portion of the bay has experienced a 1 ft. rise and fall of the tide since
the break; currents are stronger while channels and exposed flats have been created; eelgrass beds
are healthier; blooms of algae were less frequent or widespread; mats of macrophytes have
become less abundant; and sediment has changed slightly to harder substrate.
However, these changes are temporary. The inlet is part of a long term cycle13 and will
migrate south again in time. Meanwhile, the building of homes continues. The Task Force
identified several steps which were needed *,o counteract the effects of nutrient enrichment.
First, we needed to have our groundwater mapped. Cape Cod has been designated as a
sole source aquifer by the EPA. Several distinct lenses of water have been determined Cape-wide
11 Buzzards Bay Comprehensive Conservation and Management Plan, 1991.
12 Tom Cambareri, Cape Cod Commission Water Resources Coordinator, personal
communication
13Geise,G.S. 1988.
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but because of its geographic location at the "elbow1* of the Cape, Orleans is situated in a
groundwater divide. Soil conditions throughout much of the town are variable and therefore, very
little information is known about the groundwater direction of flow.-Funds were appropriated in
May, 1994 to, have the groundwater mapped which we hope will be finished by January, 1995.
Second, once the groundwater has been mapped, watersheds will be delineated-to
ascertain where the groundwater divide is between the estuaries.
Third, flushing analyses will be undertaken to determine the residence time within each
estuary. This will enable us to determine whether areas of high land-based nutrients entering the
estuary are likely to tip the balance toward eutrophication.
Fourth, a buildout analysis will be,conducted using existing zoning regulations to
determine what the town could look like at maximum density. This is a powerful planning tool
because of the visual nature of the product and the shock value such a picture portrays especially
with the technological advances with GIS systems. This analysis will also project the areas of
town where nutrients may be a real threat to the health of the bays.
Finally, .using the data, the town can then plan for the nutrients that are presently entering
the embayments as well as the nutrients that are heading toward the bays but have not gotten
there yet. The use of alternative septic'system technology, currently under review by the '
Massachusetts Department of Environmental Protection, may be approved which will allow the
town greater flexibility in dealing with nutrient enrichment in sensitive areas. With this
information the town can plan for the future and through regulations, education and guidelines,
and use of alternative waste disposal methods, it is conceivable that the nutrient problem can be
reduced over time. Since reduction of nutrients entering the estuary is a goal, public education
regarding use of fertilizers, septic system maintenance and other sources of nitrogen is critical to
achieving the goal. '
Docks and Piers
Private docks for boats have been identified as a problem for many reasons. A single
dock in a long stretch of shoreline probably poses no threat to shellfish resources. However, the
cumulative effects of docks positioned every 150 feet (SOm) (the average waterfront frontage per
lot) along the shore of narrow shallow embayments can negatively affect the shellfish resources
of an area.
Much of the clam and cowhage populations are located in a ribbon of bottom from the
edge of salt marshes that fringe our bays and rivers, to a distance of about 200 feet seaward
which is also the area where docks are located. The impacts from the docks can occur from
construction, materials/design, and location/use. On-going studies in Waquoit Bay National
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Estuarine Research Reserve and the NOAA office in Gloucester, Ma. are attempting to document
the environmental effects, both individually and cumulatively from private docks.
Waterfront landowners often feel that they have a right to have a private dock because in
Massachusetts, property ownership extends to the mean low water. However, the Colonial
Ordinance of 1637 dictates that the area below the mean high water is located in the public
tidelands for the purposes of fishing, fowling and navigation. Most of the docks extend beyond
thie mean high water and into the public tidelands which belong to everyone. Docks in Orleans
are supported by galvanized pipes, wood supports or pilings, all of varying size. Some docks are
considered "seasonal" where they are put in the water each spring and removed in the fall, or
"permanent" where they are put in place once until replacement or maintenance is necessary.
A support (pipe, piling, etc.) of any dimension displaces sediment and therefore it also displaces
shellfish habitat; the amount displaced depends on the size of the material used. We have
observed that when a dock located in soft sediment is put in and taken out each year, the
sediment around the support structure can become a "dead zone" of very soft muck. A 10" piling
may have a soft muck area of at least 24" in diameter around it where no shellfish will live and
therefore the habitat displaced or altered is about double the diameter of the piling. Although it
does not seem like much of an impact, multiplied by the number of piles in each dock and
multiplied by the number of docks in the similar type of area, the impact can be considerable.
Most docks are constructed with wood. With the introduction of CCA treated wood,
advertised to last longer than untreated wood and be especially resistant to destruction by wood
boring worms, almost all docks constructed or repaired in the last 15 years has been with
pressure treated CCA wood. There has been a debate regarding the toxicity of CCA wood in the
marine environment and only recently studies have shown the potential deleterious ramifications
of widespread use of this material14. In a hearing held in May, 1994, by the Orleans ,
Conservation Commission for a new dock in Pleasant Bay, the applicant proposed to construct
the structure with plastic "wood" manufactured from recycled milk containers. This material has
promise as an alternative to CCA treated wood but has not had enough use to provide
information of its effectiveness as a replacement.
Docks that have decking spaced close together create shading below. The environmental
ramifications of shading in northern estuaries is the subject of the continuing research.
The length of the structure and the number of bents needed to support the dock is generally a
function of depth of water at the end of the float. If a dock is inappropriately sited in a shallow
area, a boat approaching or leaving the dock may cause sediment to be displaced by severe
turbidity or "prop dredging" and can be a serious consequence which can further alter shellfish
habitat. Boats can motor through eelgrass beds to access the dock which can impact scallop
14 Weis. J.S. and P. Weis, 1994.
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resources. The turbidity of engines can impact neMy setting shellfish much as hydraulic
. harvesting for clams can be an inappropriate method of harvest during the summer15. Hydraulic
harvesting means using a pump and manifold to jet water into the substrate to dislodge shellfish
living beneath the sediment surface. Fishermen use this method where permitted'to harvest
. subtidal clams which would otherwise be very difficult to harvest.-
Erosion
Both Pleasant bay and Nauset are protected by undeveloped barrier beaches which are
constantly changing. Geise16 has indicated that the inlet to Pleasant Bay is determined by events
that fall within a 150 year cycle. As the barrier beach migrates south, the hydraulic pressure
become out of balance and pressure builds on the bay side. Eventually, the beach is breeched and
the cycle begins again. In January, 1987, we witnessed day one of the 150 year cycle. What
began as a small trickle through the beach became an inlet approximately 1.5 miles wide with
numerous sand bars within the harbor.
. . -- f
Although the upper portions of the bay received greater flushing because of the break, the
increased tidal amplitude also caused substantial erosion of coastal banks in the bay. Property
owners, who own houses on the water, arid who pay the highest tax rate, understandably
requested relief from the onslaught of erosion before houses were lost to the sea. Several houses
. were washed into the water in the neighboring town of Chatham, directly across from the new
inlet. Orleans has tried to prevent a similar circumstance. In addition to the problems in Pleasant
Bay, a similar situation occurred in the Nauset estuary which is smaller but the inlet location is
also cyclical17. In 1991, a severe northeaster flattened the dunes on the barrier beach and caused
severe erosion within the estuary. A new inlet was formed in another storm in 1992. The State
allowed eroded banks to be filled and revegetated but the storm in 1992 prevented most of the
vegetation the opportunity to become established. Property owners here were also nervous about
the loss of land and the failure of "soft" solutions and requested rock revetments to protect their
property.
15 Macfarlane, S.L. 1983
16 Geise, G.S.I 988.
17 Speer, P.E. et. al,. 1982,
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The local Conservation Commission is charged with the responsibility of permitting or
denying applications for erosion control18,19. Since 1987, the Orleans Conservation Commission
has permitted the re-vetting of approximately 1.5 miles of shoreline, with no technical basis for
knowing whether there will be a long-lasting negative effect on the productivity of the estuary
Since most of the information available on coastal engineered structures concerns structures on
"outside" or oceahfront shorelines, not the'embayments. Emotions run high on this issue.
Local Comprehensive Plan
The town is hi the process of trying to put these issues into a management framework
called a Local Comprehensive Plan. The plan will be based on resources and will encompass
diverse elements of planning for the town's future including economic development, housing
needs, infrastructure, and natural resources. The natural resources section will have a chapter on
the coastal resources.
In the coastal resources chapter, we hope to involve the neighboring towns in the
planning process since all our waters are bordered by other municipalities. At this point, a
flushing analysis will be conducted hi 1994 hi the Nauset estuary, shared by Eastham and the
groundwork has been laid for cooperative research in Pleasant Bay with the other towns, the
Cape Cod Commission and the Friends of Pleasant Bay, a non-profit organization.
Our hope is to identify all the issues, gather data, solicit opinions from residents about the
issues and offer recommendations for the future direction of the town. We will be using user
surveys, interviews, public meetings and any other tool to arrive at consensus regarding the uses
of the water and the land surrounding the water. The items outlined above concerning nutrients
are either being planned or will be completed by 1996. Recommendations will probably include
regulations and public education or guidelines for development.
If the Local Comprehensive Plan is based on resources and the residents feel that high
water quality is desirable for fishing and shellfishing, then restrictions may have to be imposed
on certain activities that would degrade the water quality. Such restrictions could include
utilizing specific waterfront shorelines for shellfish and others for private docks where the impact
to shellfish resources is minimal. However, the town must recognize, and generally does, that the
environment and natural resources are its economy.
It is clear to us that shellfish enhancement programs are not enough to maintain a fishery
resource. We have found that we must diligently work to resolve the issues identified above and
IS MGL 131 s. 40 and Chapter 160 of the Orleans Code
in ' ,-" '.' i . . ':',.
19 Town of Orleans, Chapter 16() of the Orleans Code
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that public education and consensus among the residents will be essential to correct the problems
of today. We are hopeful that a plan can be developed that takes all these elements into account
so that Orleans can continue to be the special place that it is and that shellfishing activity can take
place for generations to come.
References Cited
Anderson, D.M. 1978. Toxic dinoflagellate blooms in the Cape Cod region of Massachusetts', in
Toxic Dinoflagellate Blooms, Proceedings of the Second International Conference on Toxic
Dinoflagellate Blooms, Key Biscayne, FL, Oct. 31-Nov 5,1978. D.L. Taylor and Howard H.
Seliger, editors, Elsevier/North Holland, pp. 145-150
Belding, D.L. 1910. The scallop fisheries of Massachusetts including an account of the natural
history of the coranon scallop. Boston, MA: Commonwealth of Massachusetts Commission on
Fisheries and Game, Marine Series No.3 51 pp.
Buzzards Bay Comprehensive Conservation and Management Plan, 1991. Buzzards Bay Project.
U.S. Environmental Protection Agency and Massachusetts. Executive Office of Environmental
Affairs. Vol 1 254 pp ,
/ /
Cambareri, Thomas, Water Resources Coordinator, Cape Cod Commission, personal
communication
Cape Cod Marine Water Quality Task Force, 1988. Local efforts at controlling coastal pollution.
A Report to the Cape Cod Planning and Economic Development Commission, 42 pp.
Capuzzo, J.M. and E..E. Taylor, Jr. 1980. Preliminary investigations of local populations of the
bay scallop, Argopecten irradians irradians (lamarck) Woods Hole, MA.Woods Hole
Oceanographic Institution Annual Sea Grant Report 1978-79:26
" . ^ -
Fisk, J.D., C.E. Watson and P.O. Coates, 1967. A study of the Marine Resources of Pleasant Bay.
Commonwealth of Massachusetts Division of Marine Fisheries, Monograph Series Number 5. 56
PP- '.. " .' -.--'-'.
Geise, G.S. 1988. Cyclical behavior of the tidal inlet at Nauset Beach, Chatham, Massachusetts.
in Lecture Notes on Coastal and Estuarine Studies, Vol.29. D.G. Aubrey and L. Wishar editors.
Hydrodynamics and Sediment Dynamics of Tidal Inlets, SpringerVerlag, New York.
Macfarlane, S.L. Personal observation
Macfarlane, S.L., 1991. Managing scallops, Argopecten irradians (Lamarck) in Pleasant Bay,
\ ' - - , -, ' ,
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Massachusetts; large is not always legal, in Scallop Biology and Culture, S.E. Shumway and
P.A. Sandifer editors, World Aquaculture Society, pp 264-272.
Macfarlane, S.L. 1986. A comprehensive shellfish management plan for the Town of Orleans.
Report to the Orleans Board of Selectmen and Commonwealth of Massachusetts Division of
Marine Fisheries. 40 PP
Macfarlane, S.L. 1983. Harvesting clams with a pump - the effects on the seed. Report to Town
of Orleans. 13 pp.
Massachusetts General Laws, Chapter 130, s. 52
Massachusetts General Laws, Chapter 131 section 40, the Wetlands Protection Act
Roman, C.T. and K.W. Able et. al. 1989. An ecological analysis of Nauset Marsh, Cape Cod
National Seashore. National Park Service Cooperative Research Unit. 181 pp.
Speer, P.E. et. al., 1982, Beach changes at Nauset Inlet, Cape Cod, Massachusetts 1670-1981,
Woods Hole Oceanographic Institution Technical Report -HOI-82-40. 92 pp.
Town of Orleans, 1994. Conservation, recreation and open space plan
Town of Orleans, Chapter 160 of the Orleans Code, the Wetlands Protection Bylaw
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