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Species Description:
Both marine (Ariidae) and freshwater catfishes (Ictaluridae) are
notable for their unscaled skin, forked caudal fins, adipose fins
set anterior to the caudal peduncle, and the presence of large,
serrated spines positioned anteriorly to the dorsal fin and the
pectoral fins. Marine catfishes are separated from Ictalurids based
on the absence of barbels on the nostrils, and by body color, which
is typically steel blue dorsally, fading to silver laterally, and
white ventrally.
Ariopsis felis, the sea catfish,
is an elongate marine catfish that reaches 49.5 cm in length (Perret
et al. 1971). The head is depressed in profile, with the mouth inferior.
There are 3 pairs of barbels present. The maxillary barbels are
nearly as long as the head, while the other 2 pairs are much shorter
and set under the chin. The dorsal fin, anal fin and pectoral fins
each bear a single strong spine. The dorsal fin has 7 soft rays,
the anal fin has 19-20 rays and the pectoral fin has 6-10 rays.
A pair of ventral fins is set far posterior to the origin of the
dorsal fin. The adipose fin is black in color. The caudal fin and
anal fins are generally tipped with black, while the remainder of
the fins are dusky in color. Females have larger pelvic fins than
males (Lee 1937; Merriman 1940;
Muncy and Wingo 1983).
II. HABITAT AND
DISTRIBUTION
Regional Occurrence:
Bagre marinus ranges
from Cape Cod, Massachusetts south through coastal Florida and the
Gulf of Mexico to the Yucatan Peninsula. They are much more common
south of the Chesapeake Bay region (Muncy and Wingo 1983).
IRL Distribution:
Sea catfishes are common throughout the IRL and can be seasonally
abundant.
III. LIFE HISTORY AND POPULATION
BIOLOGY
Age, Size, Lifespan:
The maximum reported size of a sea catfish was 70.0 cm (27.6 inches)
total length (TL), with a maximum reported weight of 5.5 kg (12.2
pounds) (IGFA 2001). The lifespan may be as long as 5 - 8 years
(Benson 1982; Doermann et al. 1977).
Age 0 sea catfishes in southwestern
Florida were measured at 118 - 133 mm (4.6 - 5.2 inches) TL, while
Age 1 sea catfishes grew to 193 mm (7.6 inches) TL (Gunter and Hall
1963).
Reproduction:
Ariopsis felis reaches sexual maturity before the age
of 2 (Benson 1982). Female size at maturity has been reported within
the range of 12.6 - 26.5 cm (4.9 - 10.4 inches) (Merriman 1940;
Benson 1962). In males, maturity is thought to occur at a somewhat
larger size of approximately 25 cm (9.8 inches) in length (Merriman
1040).
Females develop flap-like fatty tissue
on their pelvic fins at maturity, and thus have larger pelvic fins
than males of the species (Lee 1937; Merriman 1940). It has been
proposed that the highly modified pelvic fins may be the site of
fertilization and may play a role in transferring fertilized eggs
to the mouth of the male for incubation (Gunter 1947). However,
it is also possible that males pick up eggs from shallow depression
in sand, as eggs, while adhesive, tend to be demersal.
Ward (1957) examined eggs of females
captured from Mississippi Sound. He noted eggs generally measured
6-8 mm in diameter in April, 9-14 mm in May, and 14-16 mm in June
and July. Eggs were enriched with yolk by early June. Motile sperm
occur in male Ariopsis felis from March - July in Mississippi
Sound. Spawning occurs from May through August in shallow bays and
estuarine waters, sometimes in less than 1 m (3.3 feet) of water
(Muncy and Wingo 1983).
Embryology:
Oval or elliptical eggs are large at fertilization, measuring 12-19
mm in diameter (Merriman 1940), are greenish in color, and develop
in the mouth of the male parent. Parental care by males offsets
low fecundity of females, which have only 20 - 65 eggs per spawning
event. Numerous small, non-functioning eggs are often found attached
to large, viable eggs. Gunter (1947) speculated that these smaller
eggs might be utilized as a food source for males brooding offspring.
Eggs of Ariopsis felis are brooded
in the mouth of males and hatch after approximately 30 days when
held under laboratory conditions at a temperature of 30 °C (86
°F) (Jones et al 1971). Larvae measure 29 - 45 mm (1.1 - 1.8
inches) TL at hatching and are retained in the mouths of male parents
until their yolk sacs are absorbed approximately 2-4 weeks after
hatching. Adult characteristics are present at absorption of the
yolk sac but juveniles tend to remain with the parent, returning
to its mouth for protection, for a short time thereafter.
Juveniles measure 68-88 mm (2.7 - 3.5 inches)
TL.
IV. PHYSICAL TOLERANCES
Temperature:
Adult sea catfishes prefer water temperatures between 25 - 36 °C
(77 - 96.8 °F)(Jones et al 1978), and actively avoid waters
where temperatures exceed 37 °C (99 °F). They also tend
to avoid water temperatures below 6 °C (43 °F) in the winter
months by migrating offshore where water temperatures are more stable,
returning to inshore areas in the spring. However, Tabb and Manning
(1961) reported that catfishes in southern Florida waters remain
inshore year-round.
Salinity:
Spawning salinity 13-40 parts per thousand (ppt) (Jones et al. 1978;
Muncy and Wingo 1983). Harvey (1972) reported that yolk sac larvae
of the sea catfish were collected at salinities ranging from 8.33
- 12.78 ppt, but not higher. Juveniles in the same study were collected
at salinities of 16.6 - 28.32 ppt, with older juveniles able to
osmoregulate in higher salinities.
Other Physical Tolerances:
Wang and Nicol (1977) reported on the effects of fuel oil on sea
catfishes and noted that the lethal concentration where 50% of the
laboratory population died was 0.14 ml/L (0.0012 ounces per gallon).
However, the presence of 0.02 ml of oil per liter (0.00018 ounces
per gallon) of water did not appear to affect feeding behavior in
sea catfishes. Raising the level to 0.08 ml fuel oil per liter (0.00071
ounces per gallon) of water caused catfishes to regurgitate food
and to lose the protective mucus layer of the stomach.
V. COMMUNITY
ECOLOGY
Trophic Mode:
Sea catfishes are opportunistic feeders that utilize mud and sand
flats as feeding grounds. Algae, seagrasses, cnidarians, sea cucumbers,
gastropods, polychaetes, shrimps, crabs, and smaller fishes comprise
the bulk of the diet (Merriman 1940). Several authors have noted
that blue crabs are a principal food source in the sea catfish diet
(Gunter 1945; Gallaway and Strawn 1974).
Males carrying
eggs or juveniles do not feed (Muncy and Wingo 1983). However, juveniles
under the protection of a male parent, feed on planktonic crustaceans
that are within range of, or enter, the parent's mouth (Merriman
1940).
Predators:
Reported predators of sea catfishes are the longnose gar, bull shark,
and large finfishes. Sea catfishes are also commonly caught as bait
for large gamefishes such as the cobia (Muncy and Wingo 1983).
Habitats:
Benson (1982) reported that juvenile sea catfishes tend to remain
in lower salinity estuaries and bays in Mississippi Sound. However,
Reid (1957), working in Texas, and Pristas and Trent (1978), working
in Florida, each reported that juvenile sea catfishes were most
commonly collected in offshore trawl sampling, rarely collected
while beach seining.
Depth preferences in gafftopsail
catfishes are apparently related to bottom type and to water temperature,
with higher abundances of gafftopsail catfishes noted when ample
organic debris is present in substrate, and water temperatures are
above 15 °C (Muncy and Wingo 1983).
Activity Time:
Gunter (1938) and Jones et al. (1978) reported that sea catfishes
sometimes school nocturnally.
VI. SPECIAL STATUS
Special Status:
Limited commercial and recreational importance.
Fisheries Importance:
COMMERICAL FISHERY:
Though edible, the sea catfish is not generally
consumed as a food fish, with many commercial and sport fishers
regarding it as a nuisance species due to its dorsal and pectoral
spines, which are large, serrated, and capable of causing painful
wounds (Muncy and Wingo 1983). However, sea catfishes do have limited
commercial importance and are harvested for industrial purposes
in commercial bottom trawling operations (Muncy and Wingo 1983)
and are taken recreationally for both bait and as food.
From
1987 - 2001, 1.04 million pounds of marine catfishes (including
both the sea catfish, Ariopsis felis, and Bagre marinus,
the gafftopsail catfish) were harvested commercially in the 5-county
area (Volusia, Brevard, Indian River, St. Lucie, Martin) encompassing
the Indian River Lagoon. The harvest was valued at $777,497, which
ranks marine catfishes thirty-fifth in dollar value to IRL counties,
and forty-second in pounds harvested.
Figure 1 below shows the
dollar value of the commercial fishery of marine catfishes to IRL
counties by year. As shown, the commercial catch ranged from
a low of $9,167 in 1989 to a high of over $344,931 in 1992.
Martin County accounted for the largest percentage of the marine
catfish harvest with 32.8% in total (Figure 2), followed by
St. Lucie County, which accounts for 21.5% of the total. Brevard,
Volusia, and Indian River Counties accounted for 19.1%, 16.9% and
9.7% of the total respectively. Interestingly, the six-year
period between 1990 - 1995 accounts for 87% of the total harvest
of catfishes in the vicinity of the IRL. Of note is that 44% of
the cumulative harvest for the entire period between 1987 - 2001
occurs in 1992, a clearly anomalous year. Martin County again accounts
for the bulk of the harvest in 1992, however, the other 4 IRL Counties
also saw greatly increased catches of catfishes in this year.
Figure
1. Annual dollar value of the commercial catch of marine catfishes
(sea catfish and gafftopsail catfish) to the 5-county area of the
Indian River Lagoon.
Figure 2. Total marine catfish (sea catfish and gafftopsail
catfish) dollar value and percentage by county for the years 1987
- 2001.
Table 1. Total dollar value
of IRL marine catfishes, Ariopsis felis and Bagre marinus, between
1987 - 2001.
Table 2. By-county annual
and cumulative percentages of the marine catfish (sea catfish and
gafftopsail catfish) harvest for the years 1987-2001.
Table 3. By-county cumulative
dollar value and percentage of total for the marine catfish (sea
catfish and gafftopsail catfish) harvest from 1987 - 2001.
RECREATIONAL
FISHERY:
Though the sea catfish is considered a nuisance species by many
anglers, it is among the thirty most harvested species within the
IRL region based on Marine Recreational Fisheries Statistics Survey
information compiled by the National Marine Fisheries Service. From
1997 - 2001 IRL anglers captured 123,022 sea catfishes either for
use as bait, or for food.
Another 238,000 sea catfishes were harvested from other inshore
waters, nearshore waters and offshore waters around the IRL. The
bulk of the recreational harvest (35.7%), was taken in nearshore
waters to the 3-mile state territorial limit. The IRL accounts for
34.1% of the harvest, while other inland waters, and offshore waters
to the 200-mile federal limit account for 38.6% and 1.7% of the
catch respectively.
Figure 3. Survey data for the sea catfish recreational fishery
showing the number of fishes harvested in East Florida waters from
1997 - 2004.
Figure 4. Summary of the
sea catfish recreational harvest and percentage of total by area
from 1997 - 2004.
Table 4. Summary data for
recreational fishery in Eastern Florida waters for the sea catfish,
Ariopsis felis, from 1997 - 2004. Data provided
by National Marine Fisheries Service, Fisheries Statistics Division,
NOAA.
Table 5. By-county annual
and cumulative percentages of the sea catfish harvest for the years
1997 - 2001. Data
provided by National Marine Fisheries Service, Fisheries Statistics
Division, NOAA.
Table 6. Summary of the
sea catfish recreational harvest and percentage of total fish captured
in each area from 1997 - 2004. Data provided by National Marine
Fisheries Service, Fisheries Statistics Division, NOAA.
VII.
REFERENCES
Benson, N.G., ed. 1982. Life history requirements
of selected finfish and shellfish in Mississippi Sound and adjacent
areas. U.S. Fish and Wildlife Service, Office of Biological Services,
Washington, D. C. FWS/OBS-81/51. 97 pp.
Doermann, J.E., D. Huddleston, D. Lipsey,
and S.H. Thompson. 1977. Age and rate of growth of the sea catfish,
Arius felis, in Mississippi coastal waters. J. Tenn. Acad.
Sci. 52(4):148 pp.
Gallaway, B.J., and K. Strawn. 1974. Seasonal
abundance and distribution of marine fisheries at a hot-water discharge
in Galveston Bay, Texas. Contrib. Mar. Sci. 18:71-137.
Gunter, G. 1938. Seasonal variations in abundance
of certain estuarine and marine fishes in Louisiana with particular
reference to life histories. Ecol. Monogr. 8(3):313-346.
Gunter, G. 1947. Observations on breeding
of the marine catfish, Gaelichthys felis (Linnaeus). Copeia
4:217-223.
Gunter, G., and G.E. Hall. 1963. Biological
investigation of the St. Lucie estuary (Florida) in connection with
Lake Okeechobee discharges through the St. Lucie Canal. Gulf Res.
Rep. 1(5):189-307.
Harvey, E.J. 1972. Observations on the distribution
of the sea catfish Arius felis larvae with and without
chorion, with respect to salinity in the Biloxi Bay - Mississippi
Sound Area. Miss. Acad. Sci. 17:77.
IGFA, 2001 Database of IGFA angling records
until 2001. IGFA, Fort Lauderdale, USA.
Jones, P.W., F.D. Martin, and J.D. Hardy,
Jr. 1978. Development of fishes in the mid-Atlantic bight. An atlas
of egg, larval, and juvenile stages. Acipenseridae through Ictaluridae.
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Vol . I : 301-307.
Lee, G. 1937. Oral gestation in the marine
catfish, Galeichthys felis. Copeia:49-56.
Merriman, D. 1940. Morphological and embryological
studies on two species of marine catfish, Bagre marinus
and Galeichthys felis. Zoologica 25(13):22i-248.
Muncy, R .J., and W.M. Wingo. 1983. Species
profiles: life histories and environmental requirements of coastal
invertebrates (Gulf of Mexico) – sea catfish and gafftopsail . U.S.
Fish and Wildlife Service, Division of Biological Services, FWS/OBS-82/11.5.
U.S. Army Corps of Engineers, TR EL-82-4. 17 pp.
Perret, W.S., B.B. Barrett, W.R. Latapie,
J.F. Pollard, W.R. Mock, G.B. Adkins, W.J. Gaidry, and C.J. White.
1971. Cooperative Gulf of Mexico estuarine inventory and study,
Louisiana. Phase I. Area description by Perret, W.S. Phase II. Biology
p. 31-69. La. Wildl. Fish. Comm. 171 pp.
Pristas, P.J. and L. Trent. 1978. Seasonal
abundance, size, and sex ratio of fishes caught in gill-nets in
St. Andrew's Bay, Florida. Bull. Mar. Sci. 28(3):581-589.
Reid, G.K., A. Inglis, and H.D. Hoese. 1956.
Summer foods of some fish species in East Bay, Texas. Southwest
Nat. 1(3):100-104.
Snelson, F.F., Jr., T.J. Mulligan and S.E.
Williams, 1984 Food habits, occurrence, and population structure
of the bull shark, Carcharhinus leucas, in Florida coastal
lagoons. Bull. Mar. sci. 34(1):71-80.
Swingle, H.A. 1971. Biology of Alabama estuarine
areas – Cooperative Gulf of Mexico estuarine inventory. Ala. Mar.
Resour. Bull. 5. 123 pp.
Swingle, H.A., and D.B. Bland. 1974. A study
of the fishes of the coastal water courses of Alabama. Ala. Mar.
Resour. Bull. 10:17-102.
Taylor, W.R. and N.A. Menezes, 1978 Ariidae.
In W. Fischer (ed.) FAO species identification sheets for fishery
purposes. West Atlantic (Fishing Area 31). volume 1. FAO, Rome.
Wang, R.T., and J.A.C. Nicol. 1977. Effects
of fuel oil on sea catfish: feeding activity and cardiac responses.
Bull. Environ. Contam. Toxicol. 18(2): 170-176.
Ward, J.W. 1957. The reproduction and early
development of the sea catfish, Galeichthys felis in the
Biloxi (Mississippi) Bay. Copeia 4:295-298.
Report by:
K. Hill, Smithsonian Marine Station
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