(DRAFT) - Taxonomy
Species weakfish
Species Id M010401
Date 26 AUG 96
TAXONOMY
NAME - weakfish
OTHER COMMON NAMES - weakie, squteague, trout, seatrout, squit, squtee, sheantts, chickwick, succoteague, drummers, saltwater trout, gray seatrout, tide runner, gray trout, sun trout, shad trout, yellow-finned trout, yellowmouth trout and summer trout
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata, Vertebrata
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Perciformes, Percoidei
FAMILY AND SUBFAMILY - Sciaenidae,
GENUS AND SUBGENUS - Cynoscion,
SPECIES AND SSP - regalis,
SCIENTIFIC NAME - Cynoscion regalis
AUTHORITY - Bloch and Schneider
TAXONOMY REFERENCES - 102
COMMENTS ON TAXONOMY -
Other common names are weakie, squteague, trout, seatrout, squit, squtee,
sheantts, chickwick, succoteague, drummers, saltwater trout, gray seatrout,
tide runner, gray trout, sun trout, shad trout, yellow-finned trout,
yellowmouth trout, and summer trout.*102*
Taxonomy - 1 (DRAFT) - Status
Species weakfish
Species Id M010401
Date 26 AUG 96
STATUS
Coded Status
EPA Indicator
Sport Fish
Game (Consumptive Recreational)
Commercial
Commercial/consumption
Migrant
Existing, FMP exists
REFERENCES FOR STATUS - 178, 102 and 162
COMMENTS ON STATUS -
The weakfish is an important commercial and sport fish.*102*
The EPA has selected the weakfish as a target species on the premise that
early life stages could experience involvement with a power generating
station's cooling-water intake system while in the vicinity.*178*
Weakfish migrate seasonally, moving north and inshore in spring and summer
to spawning and feeding areas, and returning south and offshore in
fall.*102*
The 1984 Weakfish Fishery Management Plan of the Atlantic States Marine
Fisheries Commission was reviewed in 1988. The Advisory Committee felt
that the goal of the plan and its management objectives continued to be
valid but, since full implementation of the plan was lacking, its
effectiveness at that time in improving coastal stock status was
minimal.*171*
Status - 1 (DRAFT) - Distribution
Species weakfish
Species Id M010401
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Estuarine 2
Marine 2
REFERENCES FOR NWI - 102
COMMENTS ON HABITAT ASSOCIATIONS -
Spawning along the coast of Georgia and South Carolina occurs
in the deeper waters of the sounds, off the beaches, and in nearshore
coastal waters. Larvae probably utilize subsurface currents to move to
lower salinity nursery grounds. Juvenile weakfish are euryhaline and have
been collected in fresh water. Juveniles have been collected most
frequently in trawl sampling of the deeper waters of rivers, bays and
sounds rather than in beach seine collections from shoal areas. In North
Carolina juvenile weakfish were most abundant in areas designated as
secondary nursery areas (usually shallow bays or navigations channels,
moderate depths, slightly higher salinities, and sand and/or sand-grass
bottoms. The life of the adult weakfish includes estuarine and oceanic
residence and an inshore-offshore, north-south migration pattern. Warming
of coastal waters in spring prompts an inshore and northerly migration of
adults from their wintering grounds. They enter sounds, bays and estuaries
in early spring and may either stay there through summer or return to the
ocean. A greater proportion of the adults spend summers in ocean waters
rather than in sounds and bays of northern states. Declining water
temperatures of fall are associated with formation of weakfish aggregations
and a general southerly movement along the coast. Exact location of
wintering grounds for adult weakfish are not known, but existing evidence
suggests the continental shelf from Chesapeake Bay to Cape Fear, N.C.*162*
Habitat Associations - 1 (DRAFT) - Food Habits
Species weakfish
Species Id M010401
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 102
LIFESTAGE FOOD FOOD PART
Larva Copepods Not Specified
Juvenile Copepods Not Specified
Adult Annelids Not Specified
Adult Molluscs Not Specified
General Crustaceans Not Specified
General Osteichthyes Not Specified
REFERENCES FOR GENERAL FOOD - 178 and 102
REFERENCES FOR ADULT FOOD - 178 and 102
REFERENCES FOR JUVENILE FOOD - 178 and 102
REFERENCES FOR LARVAE FOOD - 178
COMMENTS ON FOOD -
Weakfish are important top carnivores in eelgrass habitat in the Chesapeake
Bay. A shift in food with growth has been noted. Young weakfish feed
primarily on mysid shrimp and anchovies while older weakfish feed on the
cluepeid species that are abundant in a given area. Cannibalism has been
reported. Young weakfish feed mainly above the bottom and therefore are
able to coexist with other species which have more benthic feeding habits.
*102* Copepoda are also important diet items for larvae and Juveniles under
50 mm SL. Weakfish will pray on a wide range of crustaceans, annelids, and
pelagic molluscs. Larger young and adults are predominantly piscivorous.
*178*
COMMENTS ON ADULT FOOD -
-see C.Food
COMMENTS ON JUVENILE FOOD -
-see C. Food
COMMENTS ON LARVAE FOOD -
-see C. Food
Food Habits - 1 (DRAFT) - Environment Associations
Species weakfish
Species Id M010401
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
LIM Water Temperature: Specified in Comments
LIM Dissolved Oxygen: Specified in Comments
E
A Water Temperature: Unknown
A
A Dissolved Oxygen: Unknown
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 102 and 178
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 102 and 178
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 102 and 178
REFERENCES FOR FEEDING LARVAE ENVIRONMENTAL ASSOC_ - 102 and 178
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 102 and 178
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Temperature, Salinity and Dissolved Oxygen:
Laboratory tests indicate that optimum hatching of weakfish eggs occurs
between 18 and 24 degrees C. In one study, weakfish eggs in all stages
of development were collected at temperatures of 12-24 degrees C and
salinities of 29-35ppt. The young, if not spawned within estuaries, are
probably carried there by tidal currents and migrate to low salinity
nursery grounds. Upriver movement of juvenile weakfish was blocked in one
study by low oxyen concentrations (1.0-2.3 ppm) and low salinities
(<3ppt).*102*
In another study, it was found that hatching success of weakfish eggs in
the laboratory was reduced by sudden changes in temperature (+ or - 6
degrees C) or salinity (+or-5-6 ppt), turbulence, and dissolved oxygen
below 4.3 mg/l. The addition of antibiotics resulted in a four-fold
increase in hatching success.*162*
Decreasing temperatures in the fall appear to initiate movement out of the
estuary to deeper waters. Only a few weakfish of any size have been
collected below 10 degrees C in the Delaware or Chesapeake Bays. In North
Carolina, smaller weakfish have been found to remain in shallow waters
except during brief cold snaps. Dead and numb weakfish were observed in
shallow waters when water temperatures dropped suddenly to 5 degrees C.
*102*
Environment Associations - 1 (DRAFT) - Environment Associations
Species weakfish
Species Id M010401
Date 26 AUG 96
Data addressing the tolerance levels of adult weakfish to temperature,
salinity, or dissolved oxygen are sparse or non-existant. Weakfish are
sensitive to cold, and declining temperatures are believed to prompt the
fall emigration from estuaries and bays toward southern wintering
grounds.*178*
Chlorine:
Chlorine avoidance studies on a limited number of age 0+ weakfish
indicate they will avoid relatively low chlorine concentrations (less than
0.1 mg/l).*178*
DDT:
It has been hypothesized that the widespread use of DDT along the Atlantic
coast, beginning in 1945 and 1946 and its continued heavy use for the next
few years, might be related to the dramatic decline in weakfish stocks
during the 1950s and 1960s. Although it has not been demonstrated that
weakfish concentrate DDT, levels of DDT as high as 8 ppm were reported in
the gonads of female spotted seatrout and breeding of that species was
not observed in two years in the lower Laguna Madre, Texas, where
pesticide residues were consistently high.*162*
Other contaminants:
Trace levels of 15 elements were determined in tissues of 204 species of
mollusks, crustaceans, and finfish, including weakfish, to provide
baseline data to help identify potential problems involving species,
elements, or locations. No interpretative comments were provided.*162*
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
-see C.Environ.
COMMENTS ON FEEDING JUVENILE ENVIRONMENTAL ASSOC_ -
-see C.Environ.
COMMENTS ON FEEDING LARVAE ENVIRONMENTAL ASSOC_ -
-see C. Environ.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
-see C.Environ.
Environment Associations - 2 (DRAFT) - Life History
Species weakfish
Species Id M010401
Date 26 AUG 96
LIFE HISTORY
Morphology:
The weakfish is distinguished from other Cynoscion species by the following
meristic characteristics: anal fin with 11 or 12 soft rays, 11-13 gill
rakers on lower limb of first arch, 10 scales in a series between the origin
of the anal and the lateral line, and lateral line scales ranging from 76 to
86. Further, adult weakfish exhibit a characteristic dark olive green
dorsal coloration which fades to a silvery or chalky white underside. The
back and sides are burnished with purple, green, blue and gold spots which
are most numerous above the lateral line. Lateral areas typicially exhibit
dark diagonal lines and blotches and fins are dusky to yellow.*178*
Body elongate, moderately compressed; head long, snout pointed; mouth
large, oblique, lower jaw projecting; maxillary reaching to posterior
margin of pupil or beyond. Dorsal fin with a deep notch between the spinous
and soft portions, the spines flexible, third and fourth longest; anal fin
relatively small, its base ending a little in advance of that of dorsal;
caudal fin emarginate in specimens less than 300 mm, the change from a
biconcave to an emarginate condition occurring at 250-300mm; pectoral fin
not reaching to tip of pelvic fin.*162*
Sexuality:
Weakfish are dioecious. The sexes appear identical externally. The males
produce "drumming" sounds with special muscles which are vestigial in
females.*178*
Maturity:
Most males and females are sexually mature by the end of their second summer
(age 1+) and practically all are mature by the end of their third (age
2+).*178*
Mating:
Weakfish are polygamous broadcast spawners. The male produces a croaking or
drumming sound which is believed associated with mating behavior.*178*
Spawn, Larvae, and Juveniles:
Spawning, hatching and early larval development take place in the near-shore
and estuarine zones along the coast from March to October with peak juvenile
production during late April through June.*102*
Identification of weakfish eggs is difficult because of the similarity to
eggs of several sciaenid species which spawn concurrently (weakfish, silver
perch, kingfish, black drum). Weakfish spawning areas have been identified
mainly on the basis of collections of spawning adults and larvae. Weakfish
spawn in the near-shore and estuarine zones along the Atlantic coast.
Ichthyoplankton surveys indicated that the principal spawning area is from
Chesapeake Bay to Montack, Long Island, New York. Weakfish larvae have been
collected from near shore to 70 km offshore in coastal ichthyoplankton
surveys as well as within estuaries and tidal passes. *102*
Juvenile weakfish are euryhaline and have been collected in fresh water.
Juveniles have been collected most frequently in trawl sampling of the
deeper waters of rivers, bays and sounds rather than in beach seine
collections from shoal areas. Extensive sampling of North Carolina sounds
revealed that juvenile weakfish were most abundant in areas designated as
Life History - 1 (DRAFT) - Life History
Species weakfish
Species Id M010401
Date 26 AUG 96
secondary nursery areas (usually shallow bay or navigation channels,
moderate depths, slightly higher salinities, and sand and/or sand-grass
bottoms) rather than in primary nursery areas (shallow tributaries, low
salinity, mud/or mud-grass bottom). In Chesapeake Bay and Delaware Bay
young-of-the-year weakfish migrate from high to low salinity areas
throughout the summer, return to high salinity waters in fall, and leave the
estuaries by December. Juvenile weakfish are distributed along the coast
from Long Island to North Carolina at depths of 9-26 m in late summer and
fall.*102*
Adults:
The life of the adult weakfish includes estuarine and oceanic residence and
an inshore-offshore, north-south migration pattern. Warming of coastal
waters in spring prompts an inshore and northerly migration of adults from
their wintering grounds. They enter sounds, bays and estuaries in early
spring and may either stay there through summer or return to the ocean.
Sport and commercial catch records suggest movements of adults from the
North Carolina-Chesapeake Bay area to more northerly areas. Summer
residence is established throughout coastal systems from Florida to the
northern range limit. A greater proportion of the adults spend summers in
ocean waters rather than in sounds and bays of northern states. Declining
water temperatures of fall are associated with formation of weakfish
aggregations and a general southerly movement along the coast. Exact
location(s) of wintering grounds for adult weakfish are not known, but
existing evidence suggests the continental shelf from Chesapeake Bay to Cape
Fear, N.C.*102*
Growth Characteristics:
Weakfish growth is particularly rapid during the first year. In Delaware
Bay, juveniles may grow from 20 to 35 mm per month during June-September
and may attain lengths ranging from 100 to 175 mm TL throughout the range.
The variability of size within year classes is due to the extended spawning
season throughout the range.
Annulus formation on weakfish scales takes place from March through
September with the highest incidence in June and July. Growth of adult
weakfish slows during reproduction as energy is shifted to the development
of gonads. Somatic growth is rapid after spawning and annulus formation, as
indicated by the increase in the scale marginal increment from July to
October.*102*
Behavior:
Weakfish are highly visually oriented when feeding; in addition they have a
highly developed chemo-sensing response mechanism. When fright or stress
stimuli, such as increased temperature, were introduced, schooling became
tighter and more frequent. Weakfish exhibited a 35% increase in swimming
speed accompanied by tighter and more frequent schooling as temperaure was
gradually increased (0.05 degrees C/h) from the acclimated temperature range
of 19-20 degrees C to almost 29 degrees C. As the fish became acclimated to
29 degrees C their activity decreased to a point similar to that before
temperature was increased. This increased activity may serve to move the
fish from regions of adverse temperature.
Weakfish exhibited three distinct activity patterns in a laboratory study of
predator-prey interactions in eelgrass: resting, observed only at night;
Life History - 2 (DRAFT) - Life History
Species weakfish
Species Id M010401
Date 26 AUG 96
swimming observed at all light intensities and generally throughout the
daylight period; and feeding, observed during all lighted periods, but most
intense at very low light levels. The pre-capture sequence included visual
fixaton and orientation towards prey, active pursuit, and once within
striking distance (20-50 cm), rapid beating of caudal fin, and forward and
upward lunge with jaws agape and opercles spread. Weakfish consumed fewer
prey as percent area of vegetative cover increased.*102*
Predators:
No reports of predation on weakfish eggs were noted in the literature,
although jellyfish, ctenophores and planktivorous fish are likely predators.
Larval weakfish are cannibalized by larger larvae and juveniles. In
addition to reported predation by striped bass and bluefish, it is likely
that summer flounder, catfish, eels and oyster toadfish are among the common
predators of larval weakfish during the months that they provide abundant
forage. Diamondback terrapin is also a potential predator.
Significant cannibalism among weakfish has been noted, with adults and large
young feeding on young and larvae. Weakfish young are likely prey for
piscivorous birds, such as cormorants and osprey.
Bluefish, striped bass, and larger weakfish have been sited as predators of
adult weakfish. Weakfish have also been found in the stomachs of
dogfish.*178*
Parasites, Diseases, and Abnormalities:
One report indicates parasites from the phyla Protozoa, Cestoda,
Acanthocephala, Trematoda, Nematoda, Copepoda and Isopoda as associated with
weakfish. In another study, fish 51-210 mm TL were common hosts of the
isopods Lironeca ovalis and Olencira praegustator. Weakfish are among the
hosts of the parasitic dinoflagellate Amyloodinium occellatum. Weakfish
have also been found to be one of the most susceptible of marine and
euryhaline fishes in New York Bight to "fin rot" disease. This
disease may be a consequence of their residence in polluted water.
Pugheadedness has also been found in weakfish.*178*
Abundance:
Catches of weakfish throughout the species range have fluctuated widely
since the late 1800s. Total commercial foodfish landings of weakfish during
the past 40 years reveal two peaks, one during the 1940s and another during
the 1970s*102*
LIFE HISTORY CODES -
Mating System (Single breeding season): Polygamy (mal
Average Number of Offspring/Reproductive Effort: Grea
Breeding/Spawning Season: March
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Breeding/Spawning Season: October
Life History - 3 (DRAFT) - Life History
Species weakfish
Species Id M010401
Date 26 AUG 96
REFERENCES FOR LIFE HISTORY- 102, 162, and 178
Life History - 4 (DRAFT) - Management Practices
Species weakfish
Species Id M010401
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Regulating harvest of species being described
Existing Regulating harvest - setting age limits
Beneficial
Beneficial Developing/maintaining/protecting wetlands
Beneficial Maintaining unique or special habitat features [wetlands, caves,
Beneficial Controlling pollution [thermal, chemical, physical]
Adverse Shoreline modification/development
Adverse Draining wetlands, marshes, ponds, lakes
Adverse Dredging
Adverse Harvest of species using non-selective gear
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 102
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 102
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 102
COMMENTS ON MANAGEMENT PRACTICES -
Habitat Protection:
Weakfish utilize both estuarine and coastal oceanic waters at various life
history stages and times of the year. Habitat alterations within estuarine
areas are probably the most damaging to weakfish stocks since these areas
are utilized for spawning and nursery grounds. Damage and/or destruction of
estuaries have largely been by filling, dredging of navigation channels, and
pollution.*102*
Fishing Equipment:
The principal commercial methods used to harvest weakfish include trawls,
pound nets, haul seines, and several variations of gill nets. In addition,
weakfish are caught in purse seines, flotation traps, trammel nets, fyke
nets, hoop nets, and hand lines. Generally, these fisheries can be
classified as mixed opportunistic fisheries which may concentrate directly
on weakfish for brief periods of time. The most significant innovation in
commercial harvesting methods has been the use of high speed pelagic trawls
in the form of paired trawls and midwater trawls. This methodology, which
began in earnest during the mid-1070s, primarily in the New Jersey-Delaware
area of the Middle Atlantic region, harvested over 700 mt annually in 1979
and 1980.*102*
Anglers catch weakfish while trolling, chumming and drifting, and by
casting, live-bait fishing, jigging, and still fishing.*178*
Incidental Catches:
The effect of industrial or scrap landings on weakfish stocks has not yet
been determined; however, studies suggest that shrimp trawling is a
significant factor in mortality of young-of-the-year weakfish.*102*
Regulatory Measures:
Weakfish occur mainly in the territorial waters of the coastal states from
Management Practices - 1 (DRAFT) - Management Practices
Species weakfish
Species Id M010401
Date 26 AUG 96
Massachusetts to Florida. Each state exercises jurisdiction over the
fisheries within its waters to three nautical miles from shore. *102*
Fishery Management Plan:
The Atlantic States Marine Fisheries Commission Weakfish Fishery Management
Plan was adopted by ASMFC'S member states in October, 1985. The major
provisions of the plan recommended that the states in northern areas (RI to
VA) delay entry of weakfish into fisheries at least to age one, and that the
use of TEDs be promoted in southern shrimp fisheries. The plan also calls
for cooperative interstate research to understand the coastal fisheries and
biology of weakfish.
The FMP was reviewed in 1988 and the following recommendations were made:
1. Efforts should continue towards full implementation of the FMP.
2. TEDs should continue to be promoted.
3. A more coordinated coastwide research program on weakfish should be
developed.
4. ASMFC should hold annual workshops to coordinate nearshore state and
federal finfish surveys on this species and others.*171*
Management Practices - 2 (DRAFT) - References
Species weakfish
Species Id M010401
Date 26 AUG 96
References
102* Mercer, L.P. (ed.). 1985. Fishery Management Plan for the
Weakfish. (7)Mercer, L.P. North Carolina Department of Natural
Resources Morehead City, North Carolina pp 129.
162* Mercer, L. P. 1983. A Biological and Fisheries Profile of
Weakfish, Cynoscion regalis. (39). North Carolina Department of
Natural Resources Morehead City, NC pp 107.
171* Street, Mike (ed.), Eric Smith, Joseph McGurrin, Paul Perra.
1988. Atlantic States Marine Fisheries Commission: Fisheries
Management Plans for American Lobster, Atlantic Menhaden,
Northern Shrimp, Red Drum, Shad and River Herrings, Spotted
Seatrout, Summer Flounder, Weakfish. (11). Atlantic States
Marine Fisheries Commission:83.
178* Public Service Electric and Gas Company. 1984. Weakfish
(Cynoscion regalis): A synthesis of information of natural
history, with reference to occurrence in the Delaware River and
estuary and involvement with the Salem Generating Station. Salem
Generating Station 316(b) Demonstration App. XI. Public Service
Electric and Gas Company 80 Park Plaza Newark, NJ 07101. 739 pp.
References - 1