Fishes
Introduction
Commercial Fishery Resources
Description of Species
American
sand lance
sculpins
flounders
spiny dogfish
Atlantic herring
Atlantic cod
haddock
pollock
hake
butterfish
American plaice
bluefish
scup
redfish
cusk
squid
Atlantic mackerel
bluefin tuna
The
Gulf of Maine supports a wide variety of fish and shellfish species;
approximately 100 species of fish and invertebrates have been identified
throughout the Gulf of Maine-Georges Bank area. The large variety of
species in this region is due to the geographic and thermal transition
zone at Cape Cod that separates the Gulf of Maine from the Mid-Atlantic
region. The Gulf of Maine supports mainly boreal, cold temperate, non-migratory
species while the Mid-Atlantic is composed largely of warm-water, migratory
species.
Among
the pelagic (open water) species found in the Gulf of Maine are herring,
mackerel, sharks, swordfish, bluefish, bluefin tuna, capelin, and menhaden.
Most of these species exhibit clear seasonal migratory movements in
response to changes in water temperature. Demersal species (those that
live at or near the bottom) in the gulf include cod, haddock, hake,
pollock, whiting, cusk, and several species of flatfish, such as halibut
and flounder. Seasonal movements among several demersal species are
generally confined to shifts within the gulf, though some, such as pollock,
are migratory (USDOC 1993d).
The seasonal
distribution and migration of fish and invertebrate species can be grouped
into classifications of abundant species which demonstrate particular
movement patterns (Table 7). These groupings are based on their seasonal
movements within the 60-fathom (110 meter) contour (USDOC 1993d; Azarovitz
and Groslein 1987).
System
boundaries for many fish species may be provided by the circulation
patterns of the Gulf of Maine. Massachusetts Bay, located at the southwestern
end of the coastal circulation pattern, acts as a "catch basin"
for a variety of species.
Spawning
areas for several fish species occur within the general southwestern
Gulf of Maine area, including many species important to commercial fisheries,
such as pollack, Atlantic cod, herring and squid (US DOC 1993d). NOAA
reported that spawning for the Atlantic herring occurs in the Gulf of
Maine during late August through October, and that Jeffrey's Ledge is
an important spawning ground (USDOC 1989b). One of the major spawning
grounds for Atlantic Cod is Massachusetts Bay, west of Stellwagen Bank
(Campbell 1987). Spawning of the Atlantic cod occurs from December through
April. The only known spawning stock of pollock in the northwest Atlantic
uses Massachusetts Bay as its primary spawning ground (Campbell 1987).
The spawning period for this species occurs in Massachusetts Bay October
through March (Pett and McKay, 1990).
Strong
evidence exists that Stellwagen Bank provides spawning habitat for the
American sand lance (Ammodytes americanus), a ubiquitous fish in the
Stellwagen Bank area (USDOC 1993d). Schools of 500-10,000+ are found
over Stellwagen Bank (Meyer et al. 1979). The sand lance forms an important
link in the trophic chain between the zooplankton upon which they prey
and their predators: cod, haddock, silver hake, yellowtail flounder,
striped bass, bluefish, and several species of whale (Meyer et al. 1979,
Pett and McKay, 1990), such as humpback and fin whales (Sherman, et.
al. 1981; Sherman, et. al. 1984; Richards, 1965). Other species known
to spawn in the Gulf of Maine area include Fourbeard rockling (April
through June), and Witch flounder (March through June) (USDOI 1984,
Pett and McKay, 1990).
Table
7: Seasonal distribution of certain abundant fish and invertebrate species
on Georges Bank, based on bottom trawl surveys (based on table 30.3,
Azarovitz and Grosslein 1987).
Considerable
information has been collected on commercially important in the region,
but only a few studies have treated the fauna as a whole (Azarovitz
and Grosslein 1987). A historical review of the fishes of Massachusetts
Bay is provided by Collette and Hartel (1988). Table 8 presents a summary
of the results of that study.
A number
of surveys have been done which show higher than average concentrations
of certain species in the general area of Stellwagen Bank (Pett and
McKay, 1990). While surveying the northwest Atlantic, Bowman et al.
(1987) found the greatest concentrations of juvenile Atlantic cod on
Stellwagen Bank and the Great South Channel during autumn. The greatest
concentrations of haddock in the northwest Atlantic were found to occur
on Georges Bank and Stellwagen Bank (USDOI 1984), although haddock is
widely distributed throughout the Gulf of Maine. Campbell (1987) and
Lux and Kelly (1978) found haddock in high concentrations over Stellwagen
Bank from February through September. Lux and Kelly (1978) found concentrations
of redfish on the outer grounds east of Stellwagen Bank. Concentrations
of spiny dogfish on Stellwagen appear to be higher than the immediate,
surrounding areas of Massachusetts Bay, Cape Cod Bay, and the area east
of Stellwagen Bank.
Information
on the invertebrates of Stellwagen Bank is found in a comprehensive
review of the invertebrates of the north Atlantic region by TRIGOM (1974).
Hubbard et al. (1988) and Gilbert (1975) sampled invertebrate populations
found in Stellwagen Basin, and specifically, invertebrate populations
found at or near the Massachusetts Bay Disposal Site.
Pelagic
invertebrates found over Stellwagen Bank include coelenterates (jellyfish)
and molluscs (squid). Species of coelenterates found in the Gulf of
Maine include Lucernaria sp., Haliclystus sp., and Cyanea sp. (Payne
and Selzer 1986, TRIGOM 1974). Squid found on Stellwagen Bank include
the short-fin squid, Illex illecebrosus, and the long-fin squid, Loligo
pealei (Pett and McKay 1990). Other pelagic invertebrates found in this
area are the American lobster, the Northern, or Pink shrimp, the Surf
clam, the Ocean Quahog, and the Sea Scallop. Both the short-fin and
long-fin squid migrate into Massachusetts Bay waters from summer to
early autumn (Hubbard et al. 1988; Pett and McKay, 1990).
Commercial
Fishery Resources
Many
of the fish species in the Gulf of Maine area have been an important
commercial resource for the New England region (Table 9).
Data
on fishery resources is collected both from research vessel sampling
programs which provide "fishery-independent information" and
directly from the commercial and recreational fisheries in what is known
as "fishery-dependent information" (Clark 1981).
The Northeast
Fisheries Science Center (NEFSC) of the National Marine Fisheries Service
(NMFS) conducts research vessel surveys of northeast fishery resources.
The objective of the surveys is to provide realistic estimates of the
trends in populations over time. The data also provides a general quantitative
picture of the distribution and seasonal movements of the fish.
Landings
data (fishery-dependent information) has been collected by NMFS Among
the surveys conducted by NMFS are the spring and autumn bottom trawl
surveys begun in 1963 and 1968 respectively; these represent the longest
running continuous time series of research vessel sampling in the world.
The one-half hour trawls are made at sites randomly selected prior to
each survey. The objective of each tow is to catch a representative
sample of the various species and relative numbers in a particular area.
The species in the catch are counted, weighed, and measured, findings
made on age distribution, sex, feeding, and disease-related conditions
and the information entered into a cumulative trawl survey data set.
Table
9: Commercially important fish species.
Landings
data (fishery-dependent information) has been collected by NMFS port
agents through interviews with a statistically significant number of
fishermen at the dock (NMFS ceased conducting these port interviews
in 1994). This information, on what fish have been caught, how much,
and where the fish were caught are compiled in NMFS's commercial fisheries
"weigh-out" data base. The data is collected for squares of
10-minutes of longitude and latitude which encompass approximately 770
square nautical miles. Consequently, the "area fished" information
is not very precise. Further, for purposes of determining the amount
of fish caught in the Stellwagen Bank and sanctuary area, the squares
do not correspond well with either the physical feature of the bank
or the shape and orientation of the sanctuary boundary. The reliability
of the data is also affected by changes from year to year in the amount
of interview data collected (Kellogg 1990). Another factor is that the
information in the weigh-out data base is from boats greater than five
tons and a large number of the boats taking fish in the area of Stellwagen
Bank are smaller.
According
to NOAA, a number of these commercially important species are overexploited
(USDOC 1989). These include: the Atlantic cod stock in the Gulf of Maine,
pollock, haddock, redfish, witch flounder, American plaice, and yellowtail
flounder stocks. In addition, NOAA considers that spawning biomass is
below maintenance level for cod, pollack, haddock, and yellowtail flounder.
Two species are labeled by NOAA as "underexploited". These
are the current stocks of the silver hake, and stocks of red hake (USDOC
1989) (Pett and McKay, 1990; USDOC 1993d).
Descriptions
of the Species
American
Sand Lance
American
sand lance is an eel-like fish which grows to, on average, 25cm in length.
They prey primarily on copepods, but also eat fish eggs and larvae.
In turn, they are important in the diet of bluefish, cod, pollock, spiny
dogfish, silver hake, and whales. The sand lance rely on sandy bottoms
for habitat and are therefore found in somewhat patchy distributions.
They do not migrate and their geographic distributions do not vary significantly
seasonally (Azarovitz and Grosslein, in Backus and Bourne (eds.), 1987).
Sculpins
Sculpins
are not an important commercial species; they are used by fishermen
only for lobster bait. However, they are important to the ecology of
their habitat as result of their feeding behavior: they eat almost any
bottom-dweller they encounter, including most invertebrates, fish eggs,
and juvenile fish of many important species. They are demersal fish,
found on all bottom types (Avarovitz and Grosslein, in Backus and Bourne
(eds.), 1987). They are often partially buried in bottom sediments.
Sculpins are also an important forage species for carnivorous fish and
concentrate in the Great South Channel during fall (USDOI 1984e).
Flounders
Three
flounder species are considered to be of commercial importance in New
England fisheries: Winter flounder, Witch flounder, and Yellowtail flounder.
Winter flounder are also known as "blackback", and are sought
after for sport fishing as well as commercial fishing. This fish ranges
from Labrador to Georgia, and can grow to 62cm in length and obtain
the age of 12 years (Brown, 1987). They are sedentary fish, preferring
soft muddy or sandy bottoms. In winter, coastal populations move into
very shallow or estuarine waters to spawn. The Winter flounder feeds
during the day, and primarily eats small invertebrates (Azarovitz and
Grosslein, 1987).
Witch
flounder are most common along the continental shelf of Georges Bank
in waters 300-450m deep. They are demersal, preferring fine, soft ground
between rocky patches (USDOI 1984e; Avarovitz and Grosslein, 1987).
This fish is also known as "gray sole", and feeds primarily
on small invertebrates, rarely eating fish (Avarovitz and Grosslein,
1987).
Yellowtail
flounder can reach 65cm in length, however, most individuals caught
currently are less than 50cm long. They are found, as adults, distributed
widely in waters 10 to 100m deep, on sandy or sandy-mud bottoms; they
avoid soft mud or hard, rocky bottom types (Avarovitz and Grosslein,
1987; Pett and McKay, 1990). Juveniles prefer rough bottoms, which offer
more protection (Avarovitz and Grosslein, 1987). Yellowtail flounder
can reach a maximum age of about 14 years (Brown, 1987). Lux and Kelly
(1978) reported 897 yellowtail flounder from the Stellwagen Bank area
(Lux and Kelly, 1978; Pett and McKay, 1990). Heavy fishing has strongly
affected the spawning populations of the Yellowtail flounder (Azarovitz
and Grosslein, 1987).
Spiny
dogfish
Spiny
dogfish are voracious predators of almost any species smaller than themselves,
and have, therefore, a significant impact on mackerel, herring, scup,
cod, silver hake, and haddock populations. Spiny dogfish are themselves
generally 1m in length, and have no significant natural enemies (Avarovitz
and Grosslein, 1987; Brown, 1987). They are abundant in the Gulf of
Maine area where they remain year-round, avoiding warm shallows. Spiny
dogfish can live for 30-40 years (Avarovitz and Grosslein, 1987; Brown,
1987), but have a low reproductive potential; females do not reach maturity
until age 14, and generally do not exceed 4-6 pups for each two-year
gestation period (Avarovitz and Grosslein, 1987).
Atlantic
Herring
Atlantic
Herring are pelagic fish found widely distributed throughout the Gulf
of Maine (Avarovitz and Grosslein, 1987; Pett and McKay, 1990). Herring
are migratory, but maintain individual populations in certain areas
(Avarovitz and Grosslein, 1987). They range from polar ice in Greenland
to Cape Hatteras; can grow to 44cm and live to the age of 18 years (Brown,
1987). This fish feeds on copepods, euphausiids, mollusk larvae, and
fish eggs, mainly in the upper water column (Avarovitz and Grosslein,
1987; Pett and McKay, 1990). They are in turn preyed upon by many fish
as well as seabirds, porpoises and whales. The herring population of
Georges Bank was decimated by intense fishing activity in the 1960's
and 1970's, collapsing altogether in 1977. As a result of the tendency
to maintain discreet populations, there has been no appreciable increase
in herring abundance on Georges Bank since its demise (Avarovitz and
Grosslein, 1987).
Atlantic
Cod
The Atlantic
Cod is a demersal to midwater fish, ranging from surf to 366m (Pett
and McKay, 1990). Cod can grow to 90kg, however, currently they do not
get much bigger than 7 or 8kg. Cod can reach the age of 22 years (Brown,
1987). They prefer rocky or pebbly bottoms. This fish forages for clams,
crabs, shrimp, worms, squid, and many fishes; larger cod may eat skates,
flatfish, and even sculpin and searobins. Cod are a cool-water fish,
and regional abundance shifts seasonally (Avarovitz and Grosslein, 1987).
This fish spawns mainly during the winter in the Gulf of Main region
(Brown, 1987). Lux and Kelly (1978) found cod on Stellwagen Bank in
their study, with n=1465 (Pett and McKay, 1990; Lux and Kelly, 1978).
Haddock
Haddock
are bottom-feeders, foraging for crabs, worms, clams, and sometimes
fishes (Avarovitz and Grosslein, 1987). Haddock are found on sand and
gravel bottoms, in waters varying in depth from 45-135m (Pett and McKay,
1990). This fish prefers cool waters, and migrates northeastward from
most locations in the summer and fall. Haddock can reach the age of
18 years and obtain 122cm in length (Brown, 1987). Haddock have always
been a highly prized commercial species; small haddock may be more familiar
as "scrod". In the 1970's the Georges Bank haddock fishery
collapsed completely and has currently not completely recovered (Avarovitz
and Grosslein, 1987). Lux and Kelly found 4071 haddock on Stellwagen
Bank when sampling in 1978 (Pett and McKay, 1990; Lux and Kelly, 1978).
Pollock
Pollock
are generally found in large, fast-swimming schools, frequenting almost
all depths and feeding on large zooplankton and fish. They are generally
4-7 kg in weight, but have been known to exceed 30kg. Pollock prefer
cool water and rough bottoms; they are often found near wrecks. This
fish migrates seasonally to follow the cooler waters (Avarovitz and
Grosslein, 1987).
Hake
Three
species of hake are commercially important in New England regional fisheries:
White hake, Red hake, and Silver hake. Red Hake are generally 50cm in
length and 2kg in weight (Avarovitz and Grosslein, 1987), but can reach
a maximum of 75cm in length (Brown, 1987). Red hake have a life span
of approximately 12 years (Brown, 1987). They migrate seasonally according
to water temperature as well as part of their spawning pattern. Red
hake can be found from the Gulf of St. Lawrence to North Carolina (Brown,
1987). Juveniles live in empty scallop shells, which is thought to be
an instinctive protective measure. This fish is good to eat when fresh,
but does not keep well; this limits its usefulness as a directed commercial
fishery. Red Hake are often confused with White hake, especially as
juveniles. Both species occur throughout the same range, although White
hake are found distributed in general farther to the north.
Silver
hake are also known as "whiting" and prefer warmer waters
than do most of the other member of the Cod family, and ranges from
the Newfoundland Banks to South Carolina (Avarovitz and Grosslein, 1987;
Brown, 1987). This fish is a voracious feeder which ranges throughout
the water column, preying primarily upon fish and squid (Avarovitz and
Grosslein, 1987). This fish was fished extensively in the 1960's and
1970's by Soviet and East bloc fleets, and is an important commercial
fishery resource for the New England region (Avarovitz and Grosslein,
1987). Silver hake reach a maximum length of 66cm; females of the species
can live to 12 years of age whereas the males only live for about 6
years. Silver hake spawns principally in July and August in the Gulf
of Maine area (Brown, 1987).
Butterfish
Butterfish
are schooling pelagic fish which migrate seasonally within the range
from Georges Bank to Cape Hatteras. They are an important ecological
link in the food web; Butterfish eat jellyfish, copepods, and sometimes
other small fish, and are themselves preyed upon heavily by squid, bluefish,
and others. Commercially, they are fished for use in fish meal and as
bait, and to a minor extent as a foodfish. Most butterfish spawn in
inshore waters (Avarovitz and Grosslein, 1987).
American
Plaice
American
Plaice are bottom-living fish with a small midwater foraging range (Avarovitz
and Grosslein, 1987). They prefer sand-mud bottoms and are most concentrated
in the Gulf of Maine from 150-250m depth (USDOI 1984e; Pett and McKay,
1990). They are not migratory and regional populations are can be physiologically
distinguished from one another. American plaice forage for a variety
of invertebrates and very rarely eat fish. Juvenile plaice are food
for many species but adults are preyed upon only by halibut, dogfish,
and other large predators. This fish prefers cold waters (Avarovitz
and Grosslein, 1987). Lux and Kelly (1978) reported 2073 American plaice
in the Stellwagen Bank area, and greater concentrations in Massachusetts
Bay (Pett and McKay, 1990).
Bluefish
Bluefish
are a favorite of sport and commercial fishermen alike, but the recreational
catch exceeds the commercial catch. This is largely because Bluefish
have replaced striped bass, stocks of which are currently very low,
as the main recreational fishery of the Middle Atlantic. This fish is
a voracious, fast-swimming predator which feeds throughout the water
column on fishes only slightly smaller than itself. Bluefish have a
wide range of distribution, but generally prefer warmer waters and migrate
seasonally to follow water temperature (Avarovitz and Grosslein, 1987).
They are fast-growing and can live for 14 years; this fish reaches a
maximum length of 114cm (Brown, 1987).
Scup
Scup are
an important commercial and recreational fishery south of Georges Bank
to Cape Hatteras. Scup are bottom-feeders and forage for small invertebrates.
This fish moves to inshore waters in late spring and summer, where they
spawn (Avarovitz and Grosslein, 1987).
Redfish
Redfish,
also known as "ocean perch", are found generally in deep waters,
where they remain on the bottom during the day. They feed at night near
the surface. Redfish grow extremely slowly, and it often takes ten years
for an individual to reach a length of 20cm. This, coupled with the
fact that they are easily taken by trawlers during the day when on the
bottom, makes them especially vulnerable to overfishing (Avarovitz and
Grosslein, 1987).
Cusk
Cusk is
a member of the Cod family that prefers hard, rocky bottoms and is found
in deep, cold waters. This fish is solitary-living. They are not extremely
abundant throughout the Gulf of Maine area, and though harvested commercially,
this limits their usefulness for a directed fishery (Avarovitz and Grosslein,
1987).
Squid
There
are two squid species found in the Stellwagen Bank region: Shortfin
squid and Longfin squid. Shortfin squid are distributed throughout the
Northwest Atlantic from Greenland to Florida. They are a fast-growing
species with a lifespan of little more than two years. Shortfin squid
grow to maximum of 50cm mantle length, and feed primarily on small crustaceans
and some pelagic fishes such as herring or mackerel. They have been
known to feed on their young. This fish is in turn an important prey
species for many fish and mammals. They are most abundant in shelf waters
in the fall, and overwinter from the edge of the continental shelf out
to an unknown extent (Avarovitz and Grosslein, 1987).
Longfin
squid is also a shelf species, moving inshore from the shelf edge during
spring and summer, where they spawn. Like the Shortfin squid, Longfin
eat small crustaceans, fish, and often their own young, and play an
important role in the diets of many fish and marine mammals. They have
been shown to account for up to 30% of the bluefish diet (Avarovitz
and Grosslein, 1987).
Atlantic
Mackerel
The Atlantic
mackerel is a pelagic fish of commercial importance which moves inshore
in the Gulf of Maine region during spring (USDOI 1984e; Pett and McKay,
1990). This fish ranges from Labrador to North Carolina. Mackerel can
reach the age of 18-20 years and a maximum length of 56cm. In spring
and early summer mackerel spawn in the Gulf of Maine region (Brown,
1987).
Bluefin
Tuna
The Atlantic
bluefin tuna is an important recreational and commercial fish in the
Stellwagen Bank area (Jarvis 1990, Terkla 1990). The Atlantic bluefin
is a pelagic fish which is present in the Gulf of Maine from June to
October (USDOI 1984e; Pett and McKay, 1990).
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