AbStrSCt.— Commercial and rec- 

 reational catches of red drum Sciae- 

 nops ocellatus were sampled from 

 Tampa Bay and Mosquito/upper In- 

 dian River Lagoon, Florida, between 

 August 1981 and March 1983. Males 

 matured at smaller sizes and young- 

 er ages than did females. Males ma- 

 tured when they were 350-799 mm 

 FL (ages 1-3), and females matured 

 when 550-899 mm (ages 3-6). In 

 1981 and 1982, red drum spawned 

 between August and November, with 

 peak spawning occurring in Septem- 

 ber-October. Histological evidence 

 suggested that spawning occurred in 

 nearshore Gulf of Mexico waters, in 

 passes, and in the estuary. Ages deter- 

 mined from thin sections of otoliths 

 were validated by length-frequency 

 and marginal-increment analyses for 

 fish ages 1-3 and by observations of 

 oxytetracycline-marked fish for ages 

 5, 12, 16, and 18. Growth was rapid 

 through age 4 or 5 but then slowed 

 markedly. Growth rates of males and 

 females were similar on each coast. 

 Estimates for the von Bertalanffy 

 growth equation parameters K and 

 ifl were not significantly different 

 between coasts; however, L^ was 

 significantly greater on the Atlantic 

 coast. Therefore, predicted lengths 

 of Atlantic fish were greater at all 

 ages. Maximum observed lengths 

 were 980 mm on the Gulf coast and 

 1110 mm on the Atlantic coast. Max- 

 imum observed ages of sampled fish 

 were 24 years on the Gulf coast and 

 33 years on the Atlantic coast. The 

 range of 95% confidence intervals 

 for estimates of total annual mortal- 

 ity rate on the Gulf coast was 87-98% 

 for ages 2-4; on the Atlantic coast, 

 the range was 50-76% for ages 2-6. 



Reproduction, Growth, and Mortality 

 of Red Drum Sciaenops ocellatus 

 in Florida Waters 



Michael D. Murphy 

 Ronald G. Taylor 



Florida Marine Research Institute, Department of Natural Resources 

 100 8th Avenue SE, St Petersburg. Florida 33701 



Manuscript accepted 9 March 1990. 

 Fishery Bulletin, U.S. 88:.531-.542. 



The red drum Sciaenops ocellatus 

 is an estuarine-dependent sciaenid 

 found in nearshore waters (usually 

 <22 m deep) from northern Mexico 

 to Massachusetts (Yokel 1966, Ltix 

 and Mahoney 1969, Ross et al. 1983); 

 it is occasionally found north of Ches- 

 apeake Bay (Yokel 1980). Red drum 

 support important recreational and, 

 until recently, commercial fisheries in 

 most coastal areas of the U.S. south 

 Atlantic and Gulf of Mexico (Mercer 

 1984). These fisheries have recently 

 undergone strict management in 

 Florida to reduce growth and recruit- 

 ment overfishing (Swingle et al. 1984, 

 Goodyear 1987). 



Despite the importance of the red 

 drum, little is known about its life 

 history in Florida. While the spawn- 

 ing season and size at maturity have 

 been described for red dnmi in Texas 

 (Pearson 1929, Miles 1951, Matlock 

 1985) and Mississippi (Overstreet 

 1983), the spawning season in Florida 

 has been inferred only from larval 

 collections taken along the Gulf coast 

 (Springer and Woodburn 1960, Yokel 

 1966, Jannke 1971, Peters and 

 McMichael 1987). Age and growth 

 have been described for juvenile and 

 adult red drum in U.S. south Atlan- 

 tic waters (Bearden 1967, Theiling 

 and Loyacano 1976, Music and Paf- 

 ford 1984, Daniel 1988) and in the 

 northern and western Gulf of Mexico 

 (Pearson 1929; Simmons and Breuer 

 1962; Rohr 1964, 1980; McKee 1980; 

 Doerzbacher et al. 1988). In Florida, 

 larval and juvenile age and growth 

 have been studied in Tampa Bay 



(Peters and McMichael 1987), but 

 only limited data are available on 

 early growth in other areas (Kilby 

 1955, Roessler 1967). 



This paper describes reproduction, 

 age, growth, and mortality for red 

 drum on the Gulf and Atlantic coasts 

 of Florida. Weight-length and length- 

 length relationships are also pre- 

 sented. 



Methods and materials 



From August 1981 through March 

 1983, monthly samples of red drum 

 were collected from commercial and 

 recreational catches in two coastal 

 areas of Florida: (1) Tampa Bay (27° 

 40'N, 82°35'W) on the Gulf coast, 

 and (2) Mosquito/upper Indian River 

 Lagoon (28°40'N, 80°40'W) on the 

 Atlantic coast. Fish were captured 

 using a variety of gear, including 

 trammel nets, gill nets, hook-and- 

 line, and haul seines. Fork length 

 (FL) in millimeters was measured on 

 all fish in the catch. Each month on 

 both coasts, a random subsample was 

 taken, and up to ten fish per length 

 interval (<300, 400-499, 500-699, 

 700-899, and >899 mm) were mea- 

 sured for total length (TL) and stan- 

 dard length (SL), weighed for whole 

 weight (W) to the nearest ounce 

 (later converted to grams), and sam- 

 pled for gonads and otoliths (sagit- 

 tae). Gonads were preserved in the 

 field in Davidson's or Zenker's fix- 

 ative (Humason 1972), soaked in 

 water for 24 hours in the laboratory, 

 and then stored in 70% ethanol. A 



531 



