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Red Drum
Description
The red drum, also called "channel bass" or "spottail
bass," is a member of the drum family, Sciaenidae, and a close relative
of Atlantic croaker, spot, and kingfish. Red drum have elongate bodies,
reddish-bronze color, and a distinct spot or spots at the base of the
caudal fin. Scientists believe that the prominent spot on the tail confuses
predators into attacking the fish's tail instead of its head, thus giving
the fish a better chance to escape. Similar to other members of the drum
family, the red drum has an inferior mouth and a lateral line that extends
to the tip of the caudal fin. Also, red drum males produce "drumming"
sounds during the spawning season to attract females. Males also undergo
a color change during this time, becoming dark red or bluish gray on top
with a pale underside.
Habitat and Biology
Along the Atlantic coast of the United States, red drum are found from Delaware to southern Florida. They also inhabit the Gulf of Mexico, from southern Florida to northeastern Mexico. In South Carolina, red drum can be found in estuarine areas, including those in the ACE Basin. Red drum utilize different habitats as they develop. The large, adult fishes do not live in the same habitat as the subadults. In general, adults are found in nearshore and coastal waters, whereas subadults are usually found in larger creeks and rivers, although they have been observed in waters off barrier islands and sandbars. Juveniles are abundant in the shallow creeks that meander through cordgrass (Spartina alterniflora) marshes. As juveniles mature, their habitat preferences change and they move from the shallows of the estuaries into deeper inlets and along the front beaches. Because of difficulty in sampling the adult stock, very little is known of their biology. After spawning in August and September, the adults can be found around the front beaches and inlets. As water temperatures decline in the fall (late October-November), the adults move gradually offshore to deeper, warmer water. This offshore movement initiates a flurry of successful surf fishing. The movement is repeated in the opposite direction in the spring. As inshore water temperature warms in the spring, the red drum move from the deeper, warmer offshore waters to the inlets and front beaches, where they are once again available to anglers.
In general, individuals found inside the state's estuaries are juveniles; that is, they have not as yet reached sexual maturity and are frequently called subadults. Males mature at age three (68.6-76.2 cm or 27-30 inches long); females mature at age four (81-91 cm or 32-36 inches long). Reproductive activity in this species coincides with cooling temperatures and shorter days in late August. Spawning in South Carolina waters is thought to occur in coastal inlets, including St. Helena Sound, although some nearshore spawning activity is believed to occur in South Carolina during August and September. At this time, male red drum produce characteristic "drumming" sounds by contracting muscles near the swim bladder, in an effort to attract females. Fertilized eggs are pelagic, and hatching occurs in 28 to 29 hours, depending on water temperature (longer in cool water and shorter in warmer water).
Upon hatching, larvae face the difficult task of reaching nursery grounds
in the upper reaches of estuaries. They are transported to the mouths
of estuaries in currents generated by wind and tides. By swimming towards
the surface when currents are rising (flood tide) and staying close to
the bottom when the tide is ebbing so as not to be swept back out to sea,
they eventually reach the shallow tidal creeks, where they settle out
of the plankton community and spend the first few months of life. As larvae,
after yolk sac reserves are exhausted, red drum feed on zooplankton in
the water column. Once in the estuary, larval red drum feed on crustaceans
and small fishes. The smallest fish feed on copepods, and as they grow,
they eat ghost shrimp known as mysids and eventually consume grass and
penaeid shrimps. As waters cool in December, these small fishes (2.54-7.62
cm or 1-3 inches long) leave the shallow marsh creeks for the relative
warmth of deeper creeks and estuarine rivers. When water temperatures
rise in the spring, small red drum re-enter these tidal marsh creeks and
begin to grow very rapidly. At this time they feed on small fishes and
crustaceans. In May and June, these 20.3-25.4 cm (8-10 inch) fish, along
with fish of previous year classes, begin to leave the small creeks to
inhabit the open estuarine shallows. At one year of age, red drum are
25.4-30.48 cm (10-12 inches) long, and weigh just under .45 kg (1 pound).
Most meet the minimum legal size of 35.56 cm (14 inches) in October (13
months of age) and weigh on average slightly more than .45 kg. By December
(15 months of age), many of these fishes may weigh almost .9 kg (2 lbs).
Many of the 1 to 3 year old red drum inside the estuary show an interesting pattern of movements and feeding that is related to the stage of the tide. During the warmer months of the year, as the incoming tide begins to reach the smooth cordgrass, fish move into the grass, where they feed on fiddler crabs (80% of their diet), mud crabs, grass shrimp, and fishes that are associated with this structured habitat. As the tide ebbs, the red drum move off the marsh surface and are generally found on mud bars with oyster reefs in shallow water adjacent to the marsh. In the winter when water temperatures are low and the fiddler crabs are no longer active, red drum display the same pattern of tidal movement, but they become sluggish and less active since they are unable to regulate their body temperature. During the warmer months, their movements reduce their exposure to bottlenose dolphin, which is a major predator. In the coldest part of the year, they tend to be more vulnerable to predation by this marine mammal.
Species Significance
In South Carolina, red drum are classified as a gamefish and can only be bought or sold through a mariculture operation or imported from a state that allows commercial fishing. Moreover, this species can only be harvested by hook and line and by gig during the appropriate season. Drum that are less than 14 inches and are caught in South Carolina State waters must be released by law. Also, there is a bag limit of five fish per angler per day, only one of which can be longer than 27 inches.
In recent years, the red drum has been placed among the nation's important recreational and commercial species which have been fished into a state of decline. Red drum numbers in South Carolina have increased in recent years, but commercial fishing is still restricted. The fisheries for red drum have been conducted almost entirely within the internal waters of the states; therefore, management has traditionally been by individual state regulation. In South Carolina, restrictions have been issued to help manage red drum populations.
References
Mercer, L.P. 1984. A Biological and fisheries profile of the red drum, Sciaenops Ocellatus. Special Scientific Report No. 41. North Carolina Department of Natural Resources and Community Development, Division of Marine Fisheries, Morehead City, NC.
Vaughan, D.S. and T.E. Helser. 1990. Status of the red drum stock of the Atlantic coast: Stock assessment report for 1989. National Oceanic and Atmospheric Administration, Beaufort, SC.
Wenner, C.A. 1992. Red drum: Natural history and fishing techniques in South Carolina. Educational Report No. 17. South Carolina Department of Natural Resources, Marine Resources Division. Charleston, SC.
Wenner, C.A., W.A. Roumillat, J.E. Moran Jr., M.B. Maddox, L.B. Daniel III, and J.W. Smith. 1990. Investigations on the life history and population dynamics of marine recreational fishes in South Carolina. Part I. Report to Fish Restoration Act under Project F-37. South Carolina Department of Natural Resources, Marine Resources Division. Charleston, SC.
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