538 



Fishery Bulletin 88(3). 1990 



and Goodyear (1985) used tag-recapture days-at-large 

 data to estimate a total annual mortality rate of 0.73 

 during 1984-85. Also based on tag-recapture data, total 

 annual mortality rates in Texas bays were about 68% 

 during 1976-77 (Matlock and Weaver 1979) and 

 80-87% during 1975-1979 (Green et al. 1985). Matlock 

 (1984) estimated the total annual mortality rate to be 

 80% for all Texas bays during 1977-1981. 



Apparent total annual mortality rates in Florida for 

 red drum ages 2-6 are high, especially for a species 

 that may live about 25-35 years. Theoretically, fish 

 with such longevity (assuming constant mortality rate) 

 would have a natural mortality rate of only about 

 12-18%; this rate allows for survival to the observed 

 maximum ages (Royce 1972, Hoenig 1983). Our much 

 greater estimates of total annual mortality for fish ages 

 2-6 may reflect one or more of the following: (1) a 

 higher rate of natural mortality for younger fish (i.e., 

 natural mortality is not constant), (2) high fishing- 

 mortality rates within estuaries, and/or (3) emigration 

 from estuaries (sampling area) before age 4 on the Gulf 

 coast or age 6 on the Atlantic coast. In the first two 

 cases, estimates of total mortality are unbiased, al- 

 though component parts (fishing and natural mortal- 

 ity) are not the same. In the third case, total annual 

 mortality would be overestimated because older fish 

 that left the sampling area would be underrepresented 

 in the catch. 



While data for evaluating whether natural murtal- 

 ity changes with age are not available, tag-recapture 

 data suggest that fishing mortality is high and that 

 emigration does occur. Annual tag-return rates of 



