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Other Taxonomic Groupings:
Superclass: Osteichthyes
Subclass: Neopterygii
Infraclass: Teleostei
Superorder: Acanthopterygii

Species Description:
Sciaenops ocellatus is a robust, elongate and moderately compressed Sciaenid that reaches as much as 150 cm (5 feet) in length, and may weigh in excess of 41 kg (90 pounds). The head is straight in profile, with a cone-shaped snout and large, inferior mouth. The first gill arch bears 7-8 gill rakers on the lower limb. The dorsal fin bears 11 spines, the third and fourth of which are the longest. The eleventh dorsal spine is separate from the others. A deep notch separates the spinous potion of the dorsal fin from the soft dorsal fin, which has 23-25 soft rays. The anal fin has 2 spines and 8-9 soft rays. Scales are large and ctenoid, with 45 - 50 running along the lateral line, which extends to the posterior margin of the truncate caudal fin. Body color is typically an iridescent silvery gray, bronze or copper dorsally, fading to silver laterally and whitish ventrally. There are one or more dark spots set near the base of the caudal fin. The caudal fin and dorsal fins are dusky in color, while the anal and pelvic fins are more pale. No barbels are present on the chin, as occurs in other drums (Hoese and Moore 1977).

II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
Sciaenops ocellatus, the red drum, occurs from the Gulf of Maine south through Florida and the Gulf of Mexico to approximately Tuxpan, Mexico. It is most common in Florida and in coastal waters off Louisiana and Texas (Reagan 1985).

IRL Distribution:
Red drum are common throughout the IRL, but are especially abundant in the northern Indian River Lagoon in the vicinity of Cape Canaveral.

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Sciaenops ocellatus grows to 150 cm (5 feet) or more and may weigh more than 41 kg (90 pounds). They may live 40 years or longer (Taylor and Murphy 1994).

Growth is fastest during the first year of life. Johnson et al (1977) reported newly hatched red drum reached 5.1 mm (0.2 inches) total length (TL) within 12 days of hatching. Parrish (1968) studied growth in red drum, reporting that juveniles hatched in winter grew to 71 mm (2.8 inches) standard length (SL) by March, 109 mm (4.3 inches) by April, 147 mm (5.8 inches) by May, and 216 mm (8.5 inches) by June. Roessler (1970) reported that red drum in the Everglades grew 20 mm (0.79 inches) TL per month during the fall and winter months and were approximately 81 mm (3.2 inches) TL by March.

Perret et al (1980) reported growth rates per day in tagged and recaptured Florida red drum. In this study, 282 mm (11.1 inches) fishes grew approximately 0.66 mm (0.03 inches) per day (Topp 1963); 310 mm (12.2 inches) fishes grew 0.58 mm (0.03 inches) per day (Beaumariage and Wittich 1964); 350 mm (13.8 inches) fishes grew 0.35 mm (0.01 inches) per day; (Beaumariage 1964); 420 mm (16.5 inches) fishes grew 0.24 mm (0.009 inches) per day; and 655 mm (25.8 inches) fishes grew 0.098 mm (0.004 inches) per day (Beaumariage and Wittich 1964).

Etzold and Christmas (1979) reported mean standard lengths of red drum by age in Mississippi. Age I fishes were approximately 340 mm (13.4 inches) , Age II were 540 mm (21.3 inches); Age III were 640 mm (25.2 inches); Age IV were 750 mm (29.5 inches); and Age V were 840 mm (33.07 inches).

Reproduction:
Red drum are fully mature at lengths of approximately 305 - 750 mm (12 - 29.5 inches) TL when they are 4-5 years old (Pearson 1928). Males begin maturing at 1-3 years old, females at 3-6 years.

Red drum in some areas migrate from estuaries to the deeper waters of inlets and bay mouths for spawning, while others spawn within estuaries. In eastern Florida, spawning occurs during the fall when daylight hours begin to shorten and water temperatures begin to cool. On Florida's Gulf coast, spawning begins in September, peaking in October (Yokel 1966). In the northern Gulf of Mexico, red drum spawn from August through December. In Alabama spawning occurs from mid-August through December, while in Mississippi, spawning occurs from from September through November.

Spawning behavior in red drum was described by Guest and Lasswell (1978). Males initiate spawning by vibration of the swim bladder to produce a drumming sound. Drumming increases in intensity around dusk as males encounter females and swim nearer to them, nudging them in their abdomens. When females are finally induced to release eggs, males swim close to them, releasing milt. Spawning behavior in this study peaked between 9:30 - 10:00 p.m.

Red drum held in mariculture ponds in Florida produced 20,000 - 2 million eggs per spawn (Roberts et al1978).

Embryology:
Eggs of Sciaenops ocellatus are spherical in shape, measure 0.80 - 0.98 mm (0.03 - 0.04 inches) in diameter and contain 1 or more clear oil droplets (Johnson et al 1977). Optimum hatching and survival temperature was estimated by Holt et al. (1981) to be 25 °C (77 °F) and 30 parts per thousand (ppt), with hatching success decreased at higher temperature and lower salinity. Eggs were noted to sink at salinities below 20 ppt.

Eggs hatch as larvae 4-6 mm (0.16 - 0.23 inches) total length. At this stage, the dorsal and caudal finfolds are continuous with the well developed caudal fin, and the pelvic and pectoral fins are underdeveloped. Many brown chromatophores are present at the bases of the anal fin, and the dorsal fin (Pearson 1928).

Postlarvae are approximately 7 mm (0.27 inches) TL, and retain a small area of the ventral finfold between the anal fin and the vent. Chromatophores are now present on the head and along the length of the body. By 10 mm (0.39) TL, postlarvae are heavily pigmented. Color patterns develop at approximately 25 mm (0.98 inches) TL. By this point, scales and teeth have now developed. Body color becomes silvery with a row of 5-7 blotches of heavy pigment along the lateral line (Pearson 1928).

Postlarvae spend approximately 20 days in the water column before becoming demersal (Rooker et al 1999).

IV.  PHYSICAL TOLERANCES

Temperature:
Red drum tolerate widely varying temperatures of 2 - 37.5 °C (35.6 - 99.5 °F). However, sudden environmental changes cause physical stress and can lead to mass mortality (Gunter 1941). Based on laboratory studies by Holt et al. (1981) hatching success and larval survival is optimized at temperatures of 25 °C and 30 ppt salinity, with better survival and growth at 25 - 30 °C (77 - 86 °F). Postlarvae and juveniles less than 120 mm (4.7 inches) also had a preference for waters of 25 °C (Loman 1978).

Salinity:
Red drum tolerate both low and high salinity and have been collected from waters where salinity was measured between 0.14 - 50 ppt (Gunter and Hall 1962; Simmons and Breuer 1962). They can be successfully acclimated to freshwater (Lasswell et al 1977).

Holt et al. (1981) showed that eggs of red drum float when salinity is above 25 ppt, but sink at salinity below 20 ppt, likely reducing egg survival in low salinity waters. Postlarvae and juveniles less than 120 mm (4.7 inches) showed a preference for 30 - 35 ppt salinity (Loman 1978).

V.  COMMUNITY ECOLOGY

Trophic Mode:
Sciaenops ocellatus are major predators of fishes and decapods within estuaries. The smallest juveniles, less than 10 mm (0.4 inches) TL, consume primarily copepods. Juveniles 10 - 49 mm (0.4 - 1.9 inches) TL consume up to 67% mysids; juveniles 50 - 69 mm (1.9 - 2.7 inches) consume up to 57% fishes; juveniles 70 - 99 mm (2.7 - 3.9 inches) TL consume up to 60% decapods; juveniles 100 - 149 mm (3.9 - 5.7 inches) consume mainly decapods, fishes, and mysids; while those 150 - 180 mm (5.9 - 7.0 inches) consume decapods and smaller fishes (Bass and Avault 1975).

Adults feed mostly on fish, shrimp and crabs. Important fish species in the diet include menhaden, anchovies, and inshore lizardfish. Boothby and Avault (1971) reported that fishes are apparently more important to the diet during the winter and spring months, while a changeover to crabs is observed in the summer and fall.

Predators:
The role red drum play as prey for other species has not been widely documented.

Habitats:
Though red drum inhabit both inshore and offshore waters, the majority of life cycle is spent in nearshore waters and estuaries (Reagan 1985). Postlarvae and small juveniles move into rivers, bays, canals, and the mangrove creeks of estuaries (Miles 1950, Bass and Avault 1975, Holt et al 1983; Peter and McMichael 1987), utilizing these areas as well as seagrasses as nursery grounds. Older juveniles are commonly captured over sand and mud substrates, tending to move into wetlands on the high tide (Bass and Avault 1975). Subadults are also found in these habitats, tending to aggregate in seagrasses and over oyster bars, mud flats and sand bottoms.

Adults on Florida's Atlantic coast are found primarily in nearshore waters, except in east central Florida, where they are found in large numbers within the Indian River Lagoon, especially in the northern reaches of the Lagoon around Cape Canaveral. Gulf of Mexico populations tend to travel in schools in nearshore waters, with some returning to estuaries in the summer. Many of the larger fishes however, remain in nearshore waters year-round (Simmons and Breuer 1962).

Edge effects are apparently important to red drum juveniles, as they are more commonly collected on patch edges than in the interiors of seagrass flats (Reagan 1985).

Activity Time:
Sciaenops ocellatus feed both in daylight and in the evening hours. Juveniles measuring 65-85 mm (2.6 - 3.3 inches) TL fed primarily on grass shrimp during daylight hours, but switched to spot (Leiostomus xanthurus) during the evening hours (Bass and Avault 1975).

VI. SPECIAL STATUS

Special Status:
Recreationally important.

Fisheries Importance:

COMMERCIAL FISHERY:
The U.S. total harvest for red drum from 1987 - 2001 was 9.04 million pounds, with a value of approximately $9.4 million. The average harvest per year is approximately 600,000 pounds, with the bulk of the harvest taken in Louisiana.

There has been no reported commercial fishery for red drum in Florida since 1988 when commercial harvesting was essentially banned. However, even when the red drum fishery was active, the commercial harvest accounted for only 5-16% of the total catch on the Atlantic coast and 14-36% on the Gulf coast (Murphy 2005).

RECREATIONAL FISHERY:
The red drum is one of the most important recreational species throughout its range due to its intense fight and popularity as a food fish. Louisiana typically has the largest annual recreational harvest of red drum, with most catches higher in inshore waters rather than in offshore waters.

Since 1987 in Florida, there has been an increasing trend in total number of fishing trips directed at red drum each year. Since 1995, there have been approximately 1.1 annual directed fishing trips for red drum on the Atlantic coast, and 1.8 million since 1995 on the Gulf coast.(Murphy 2005). Fishing mortality rates for Sciaenops ocellatus have been increasing on both coasts since 1990, reaching historical highs in the early 2000s (Murphy 2005). The 2003 recreational harvest in Florida totaled 2.3 million pounds. Landings were greater on the Gulf coast, which accounted for approximately 69% of statewide landings. 2003 landings were 17% higher than occurred in the previous 5 years.

The Florida Fish and Wildlife Conservation Commission regulates the fishery for red drum. Current regulations state that to be harvested, red drum must measure not less than 18, or more than 27 inches. There is a bag limit one per person per day.

Figure 1.  Survey data for the red drum recreational fishery showing the number of fishes harvested in East Florida waters from 1997 - 2004. Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.

Figure 2.  Summary of the red drum recreational harvest and percentage of total by area from 1997 - 2004. Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.

Table 1.  Summary data for recreational fishery in Eastern Florida waters for the red drum, Sciaenops ocellatus, from 1997 - 2004.   Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.

Table 2.  By-county annual and cumulative percentages of the red drum harvest for the years 1997 - 2001.  Data provided by National Marine Fisheries Service, Fisheries Statistics Division, NOAA.

Table 3.  Summary of the red drum 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 

Arnold, C.R., W.H. Bailey, T.D. Williams, A. Johnson and J.L. Lasswell. 1977, Laboratory spawning and larval rearing of red drum and southern flounder. Proc. Annu. Conf. Southeast Assoc. Game Fish Comm., 31: 4377–440.

Bass, R.J., and J.W. Avault, Jr. 1975. Food habits, length-weight relationship, condition factor and growth of juvenile red drum (Sciaenops ocellata) in Louisiana. Trans. Am. Fish. Soc.104:35-45.

Beaumariage, D.S. 1964. Return from the 1963 Schlitz tagging program. Fla. Board Conserv. Mar. Res. Lab. Tech. Ser. 43. 34 pp.

Beaumariage, D.S., and A.C. Wittich. 1966. Return from the 1964 Schlitz tagging program. Fla. Board Conserv. Mar. Res. Lab. Tech. Ser. 47. 51 pp.

Boothby, R.N., and J.W. Avault, Jr. 1971. Food habits, length-weight relationship, and condition factor of the red drum Sciaenops ocellata in southeastern Louisiana. Trans. Am. Fish. Soc. 100:290-295.

Brown-Peterson, N.J. 2003. The reproductive biology of spotted seatrout. In Biology of the spotted seatrout (S. A. Bortone, ed.) p. 99-133. CRC Press, Boca Raton, FL.

Guest, W.G., and J.L. Lasswell. 1978. A note on courtship behavior and sound production of red drum. Copeia 1978:337-338.

Hoese, H.D., and R.H. Moore. 1977. Fishes of the Gulf of Mexico. Texas A&M University Press, College Station. 327 pp.

Holt, G. J., S. A. Holt, and C. R. Arnold. 1985. Diel periodicity of spawning in sciaenids. Mar. Ecol. Prog. Ser. 27:1-7.

Holt, J., C.L. Kitting, and C.R. Arnold. 1983. Distribution of young red drum among different sea grass meadows. Trans. Am. Fish. Soc. 112:267-271.

Johnson, A.G., W.A. Fable, Jr., T.D. Williams, and C.R. Arnold. 1977. Description of reared eggs and young larvae of the red drum Sciaenops ocellata. Pages 118-127 in Marine Fish Propagation Study, Federal Aid Project F-31-R: - Completion Rep. Texas Parks Wildlife Department.

Lee, W. Y., G. J. Holt, and C. R. Arnold.1984. Growth of red drum larvae in the laboratory. Trans. Am. Fish. Soc. 113:243–246.

McMichael, R. H., and K. M. Peters. 1989. Early life-history of spotted seatrout, Cynoscion nebulosus (Pisces: Sciaenidae), in Tampa Bay, Florida. Estuaries 12:98-110.

Miles, D.W. 1950. The life histories of the spotted seatrout Cynoscion nebulosus and the redfish Sciaenops ocellata. Tex. Game Fish Oyster Comm., Mar. Lab. Annu. Rep. (1949-1950):66-103.

Murphy, M.D. 2005. A stock assessment of red drum, Sciaenops ocellatus, in Florida: status of the stocks through 2003. Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research institute, St. Petersberg, FL. 36 pp.

Murphy, M.D. and R.E. Crabtree. 2001. Changes in the age structure of nearshore adult red drum off west-central Florida related to recruitment and fishing mortality. North American Journal of Fisheries Management 21:671-678.

Murphy, M. D., and R. G. Taylor. 1994. Age, growth and mortality of spotted seatrout in Florida waters. Trans. Am. Fish. Soc. 123:482-497.

Parrish, P.R. 1968. Seasonal occurrence of marine and freshwater fishes in relation to salinity and temperature in the lower Ochlockonee River, Florida. M.S. Thesis. Florida State University, Tallahassee. 79 Pp.

Pearson, J.C. 1928. Natural history and conservation of the redfish and other commercial sciaenids on the Texas coast. Bull. U.S. Bur. Fish. 4:129-214.

Perret, W.S., J.E. Weaver, R.O. Williams, P.L. Johansen, T.D. McIlwain, R.C. Raulenson and W.M. Tatum. 1980. Fishery profiles of red drum and spotted sea trout. Gulf States Mar. Fish. Comm. No. 6. 60 pp.

Reagan, R.E. 1985. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico) -- red drum. U.S.Fish Wildl. Serv. Biol. Rep. 82(11.36). U.S. Army Corps of Engineers, TR EL-82-4. 16 PP.

Roberts, D.E., Jr., B.V. Harpster, and G.E. Henderson. 1978. Conditioning and induced spawning of the red drum (Sciaenops ocellata), under varied conditions of photoperiod and temperature. Proc. Annu. Meet. World Maricult. Sot. 9:311-332.

Roessler, M.A. 1970. Checklist of fishes in Buttonwood Canal, Everglades National Park, Florida, and observations on the seasonal occurrence and life histories of selected species. Bull. Mar. Sci . 20(4) :861-890.

Rooker J.R., S.A. Holt, G.J. Jolt, and L.E. Fuiman. 1999. Spatial and temporal variability in growth,mortality, and recruitment potential of post-settlement red drum, Sciaenops ocellatus, in a subtropical estuary. Fish. Bull. 97:581–590.

Simmons, E.G., and J.P. Breuer. 1962. A study of redfish, Sciaenops ocellata Linnaeus, and black drum, Pogonias cromis Linnaeus. Publ. Inst. Mar. Sci. Univ Tex. 8:184-211.

Topp, R. 1963. The tagging of fishes of Florida, 1962 program. Fla. Board Conser. Mar. Res. La b. Prof. Pap. Ser. 5. 76 Pp.

Yokel, B.J. 1966. A contribution to the biology and distribution of the red drum, Sciaenops ocellata. M.S. Thesis. University of Miami, Coral Gables. 160 pp.

Report by:  K. Hill, Smithsonian Marine Station
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Page last updated: September 29,  2005