Species Description: The red drum, Sciaenops ocellatus, has a elongate, moderately compressed body with a relatively straight profile along the ventral surface (Chao 2002). Like similar species, the head slopes forward, terminating in a blunt snout and a large, inferior mouth (Robins et al. 1986). Pores are present on the head, 5 on the chin and 10 on the snout (Chao 2002). Unlike several drum species, the chin lacks barbels. Background body coloration is iridescent silvery copper, which is darker above. One to several black spots about the size of the eye are present on the sides from just before the posterior tip of the dorsal fin to the base of the caudal fin. Usual fin ray counts are as follows: dorsal fin = 10 spines, posterior section with 1 spine and 23-25 soft rays; anal fin = 2 spines and 8-9 soft rays, with the second spine about half the height of the first soft ray (Chao 2002).
Potentially Misidentified Species: The red drum and the spot, Leiostomus xanthurus, are the only two local species of drums without chin barbels (Robins et al. 1986). The spot has a distinctly forked caudal fin, a brown dot on the shoulder, and 12-15 narrow, dark diagonal lines on the upper body. The average size of L. xanthurus typically does not exceed 36 cm (see “Age, Size, Lifespan”).
Regional Occurrence: The range of S. ocellatus extends from Massachusetts to northern Mexico, including the Gulf of Mexico (Robins et al. 1986; Chao 2002). Fishes are found in a variety of coastal habitats (see 'IRL Distribution'). Some studies have linked the predation and growth of larval and juvenile red drum to the type of habitat in which they reside. Seagrass beds and salt marshes may be considered to be the most favorable habitats to increase survivorship, with shoal grass, Halodule wrightii (formerly H. beaudettei), cited as the optimal vegetation (Rooker & Holt 1997; Rooker et al. 1998).
IRL Distribution: Little information is available concerning the distribution of the red drum in the IRL, but the species can be found throughout the lagoon on submerged tidal flats, in seagrass beds and salt marshes, among mangrove roots and in shallow nearshore waters off nearby sandy beaches.
Age, Size, Lifespan: The maximum documented size of the red drum is 1.6 m, but individuals under 1 m are more common (Chao 2002). Growth rates vary with habitat type and age of the fish, but newly settled juveniles grow at an overall reported rate of 0.45 mm per day (Stunz et al. 2002). Males mature between 1 and 3 years old, while females reach maturity at 3-6 years (FWCC 2008). The maximum reported age for the red drum is 60 years (FWCC 2008).
Abundance: Detailed abundance records for S. ocellatus populations within the IRL are scarce. However, studies conducted by Rooker & Holt (1997) on populations in a Texas estuary revealed densities up to 3.4 individuals per square meter.
Reproduction & Embryology: Reproductive and embryological studies on the red drum are elusive, despite the success of the species in aquaculture and stock enhancement programs. Spawning occurs in the late summer and early fall from estuaries to nearshore waters (Rooker & Holt 1997; FWCC 2008), and planktonic larvae settle and metamorphose into juveniles in a variety sheltered coastal habitats.
Temperature: Little information is available concerning the physical tolerances of S. ocellatus. However, its natural range encompasses marine and estuarine habitats in temperate to tropical climate zones. This pattern of distribution suggests that red drum populations prefer and/or require somewhat warm, saline waters in order to thrive.
Trophic Mode: The red drum feeds on a variety of crustaceans, mollusks and fishes (Chao 2002), and is quite effective at using its powerful jaws to break through hard-shelled prey (Ruehl & DeWitt 2007). Studies on populations in Texas revealed that S. ocellatus adjusts its diet to the seasonal variability of prey items, consuming mostly white shrimp, Penaeus setiferus, in the fall, and gulf menhaden, Brevoortia patronus, in the spring (Scharf & Schlight 2000). Swimming crabs of the genus Callinectes were abundant and consumed year-round. It is likely that similar trends in diet variation among red drum exist in other locations where prey availability fluctuates seasonally.
Predators: Studies have been conducted to assess the importance of habitat on deterring predation of larval and juvenile red drum by the pinfish, Lagodon rhomboides (Rooker et al. 1998) (see ’Habitat & Distribution’). Other information concerning predators of S. ocellatus is scarce, but additional fish species and a variety of coastal birds likely consume red drum as well.
Associated Species: Although there are no obligate associations documented between the red drum and other species, S. ocellatus is commonly found alongside organisms from the various coastal marine and estuarine habitats in which it resides. For more extensive information on these ecosystems and their associated species found in and around the IRL, please visit Habitats of the IRL.
Economic & Ecological Importance: The red drum is widely consumed and is the basis of an important recreational fishery in Florida waters (e.g. Robins et al. 1986; Chao 2002; FWCC 2010). Current Florida recreational fishing regulations for S. ocellatus allow the collection of one fish per person per day, 18-27 inches in length. Gigging, spearing and snatching are prohibited, as is harvesting in federal waters (FWCC 2010). The red drum has also become a successfully cultured species, which may prove a beneficial first step in conserving similar species through captive breeding programs (Chao 2002).
Chao, NL. 2002. Sciaenidae. pp. 1583-1639. In: The living marine resources of the Western Central Atlantic. Volume 3: Bony fishes part 2 (Opistognathidae to Molidae), sea turtles and marine mammals. Carpenter KE (Ed.). FAO species identification guide for fishery purposes and American Society of Ichthyologists and Herpetologists special publication no. 5. FAO, Rome. pp. 1375-2127.
FWCC. 2008. Red drum, Sciaenops ocellatus. Florida Fish & Wildlife Conservation Commission: Red Drum. Online at http://myfwc.com/wildlifehabitats/profiles/saltwater/drums/red-drum/.
FWCC. 2010. Florida Saltwater Fishing Regulations. Florida Fish & Wildlife Conservation Commission. Online at http://myfwc.com/fishing/saltwater/recreational/.
Robins CR, Ray GC, and J Douglas. 1986. A Field Guide to Atlantic Coast Fishes. The Peterson Field Guide Series. Houghton Mifflin Co., Boston. 354 pp.
Rooker, JR & SA Holt. 1997. Utilization of subtropical seagrass meadows by newly settled red drum Sciaenops ocellatus: patterns of distribution and growth. Mar. Ecol. Prog. Ser. 158: 139-149.
Rooker, JR, Holt, GJ & SA Holt. 1997. Condition of larval and juvenile red drum (Sciaenops ocellatus) from estuarine nursery habitats. Mar. Biol. 127: 387-394.
Rooker, JR, Holt, GJ & SA Holt. 1998. Vulnerability of newly settled red drum (Sciaenops ocellatus) to predatory fish: is early-life enhanced by seagrass meadows? Mar. Biol. 131: 145-151.
Ruehl, CB & TJ DeWitt. 2007. Trophic plasticity and foraging performance in red drum, Sciaenops ocellatus (Linnaeus). J. Exp. Mar. Biol. Ecol. 349: 284-294.
Scharf, FS & KK Schlight. 2000. Feeding habits of red drum (Sciaenops ocellatus) in Galveston Bay, Texas: seasonal diet variation and predator-prey size relationships. Estuaries 23: 128-139.
Stunz, GW, Minello, TJ & PS Levin. 2002. Growth of newly settled red drum Sciaenops ocellatus in different estuarine habitat types. Mar. Ecol. Prog. Ser. 238: 227-236.