Murphy and Taylor: Saaenops ocellatus in Florida waters 



539 



70-80% occurred in southwest Florida during the 

 1961-65 Schlitz Tagging Programs, and the average 

 tag-return rate throughout the state was 46% (Beau- 

 mariage 1969). More recent annual tag-return rates in 

 Florida were 11-25% (Murphy and Taylor 1985) and 

 12% (Rago and Goodyear 1985), but if these are ad- 

 justed to account for a probable low tag-reporting rate, 

 e.g., 36% in Texas (Green et al. 1983), then actual an- 

 nual recapture rates in Florida could still be high: 

 31-69%. Limited data on the emigration of red drum 

 suggest a little exchange from estuarine to nearshore 

 waters. Subadult red dnmi tagging studies within Tam- 

 pa Bay have shown that about 2-6% of recaptured red 

 drum came from outside the Bay (Murphy and Taylor 

 1985); similar results (1.4%) were reported for the 

 Texas coast (Osburn et al. 1982). Fishing effort and 

 "catchability" of red drum are probably lower in near- 

 shore waters than within the estuary, which could 

 cause the rates of emigration to be underestimated. 



Weight-length and length-length relations 



Weight-length regressions (Table 6) were not signifi- 

 cantly different (;)>0.05) between sexes on each coast, 



although the slopes and elevations were different be- 

 tween coasts with sexes combined. 



slope 

 elevation 



df=l, 971 

 df=l, 972 



F = 18.96 

 F = 27.5. 



Predicted weights for subadult red drum were similar; 

 e.g., the predicted weight of a 500-mm fish is about 1.4 

 kg on both coasts. However, adult red drum on the Gulf 



coast were heavier at a given length than they were 

 on the Atlantic coast; e.g., a 900-mm fish weighs 8.8 

 kg on the Gulf coast and 8.3 kg on the Atlantic coast. 

 Length-length regressions show that total length and 

 standard length increase more rapidly than fork length 

 as fish get larger (Table 7). Total length is about 1% 

 greater at 300 mm FL and 6% greater at 1000 mm FL. 

 Standard length is 18% less than fork length at 300 

 mm FL but only 12%. less at 1000 mm FL. 



Summary 



The following are significant features of the life history 

 of red drum in Florida: rapid growth through age 4 or 

 5, relatively early sexual maturation (total maturity by 

 age 3-6), a discrete peak in spawning activity during 

 September-October, a life span of up to about 35 years, 

 and spawning grounds located in nearshore waters, in 

 passes and inlets, and inside large estuaries. These 

 characteristics and the apparently high rate of annual 

 mortality for red drum ages 2-6 suggest that only a 

 small portion of the population survives to reach 

 maturity. However, this annual rate of mortality (disap- 

 pearance) has a component of emigration that warrants 

 investigation. Recent management measures enacted 

 by the Gulf of Mexico Fishery Management Council and 

 the Florida Marine Fisheries Commission have limited 

 fishing on the spawning stocks and have reduced fish- 

 ing pressure on the immature fish. 



