Fishery Bulletin 88(4), 1990 



capture (Table 1). The differences were attributed to 

 growth after mark formation. Gulf bluefish were con- 

 sistently greater in length for age compared with 

 Atlantic bluefish. The difference gradually increased 

 through age-4, the ma.ximum age of the available Atlan- 

 tic samples. 



The Gulf samples included large fish (>600 mm FL) 

 in relatively large numbers (>30% of the sample) only 

 in May and June 1978. During other years, the large 

 fish made up only 4% or less of the Gulf samples. 

 Bluefish of this size are not commonly found in the 

 Gulf. Fable et al. (1981) reported that these fish were 

 decidedly larger than Gulf bluefish observed in 1973 

 and 1977. Atlantic samples included fish estimated to 

 be no older than age 4 and FL less than 600 mm. 



A general comparison with some previous bluefish 

 studies was made (Fig. 3). All other studies used scales 

 to age bluefish and did not report validation. Scale 

 studies were used, as no similar otolith studies could 

 be obtained. Wilk (1977) analyzed scales from bluefish 

 sampled along the Atlantic coast. His results showed 

 slower gi-owth to age-1 than either Gulf or Atlantic 

 samples from this study. By age-2 a larger rate of 

 growth had converged his reported lengths to just short 

 of the Gulf samples from this study, a relationship 

 maintained until age-7 at which point small sample sizes 

 may have contributed to errors. Reported lengths- 

 at-age from scales of Long Island Sound bluefish 

 (Richards 1976) were similar to those of this study. 

 North Carolina spring-spawned bluefish aged by scales 

 (Lassiter 1962) fall within range of Gulf bluefish from 

 this study, but have shorter lengths at each age. 



The von Bertalanffy (1938, 1957) theoretical growth 

 parameters derived from this study are: 



Gulf: k = 0.180, 1^ = 944, t„ = -1.033 

 Atlantic: k = 0.096, 1^ = 1,019, t,, = -2.493. 



Growth coefficient (k) for Gulf bluefish is within the 

 range of those reported by Lassiter (1962) for North 

 Carolina spring-spawned (0.103) and summer-spawned 

 (0.342) and by Manooch (1979) for Gulf and Atlantic 

 maximum age-8 (0.230) and maximum age-9 (0.340) 

 bluefish. The high growth coefficient of Gulf bluefish 

 reflects the relatively rapid initial growth. The large 

 bluefish taken in the summer of 1978 may influence 

 this coefficient. 



Otoliths appear to be better than either scales or 

 vertebrae for ageing Gulf bluefish. Based on the per- 

 cent of opaque edge occurrence and the close fit with 

 other studies, it appears that age marks on the otoliths 

 of Gulf bluefish are formed annually. Direct validation 

 of age, which was not possible in this study, should be 

 included in future studies. The cause of a higher per- 

 cent of otoliths with opaque edges in the months of 



f ; ' I U A U D ft f, [ 



Figure 3 



Meai) length iif bluefish from the ( nJf of Me.xico and the U.S. Athmlic 

 coast by age in years from this and other published studies. North- 

 ern Gulf of Mexico, this study (»); U.S. South Atlantic coast, this 

 study ( + ); Long Island Sound. NY (Richards 1976), (0); New York 

 Bight (Hamer 1959). (O); Atlantic coast (Wilk 1977), (D); North 

 Carolina (Lassiter 1962), (A). 



June and July in Gulf bluefish should also be a point 

 of further investigation. 



Acknowledgments 



I wish to thank Drs. Charles S. Manooch III of the 

 National Marine Fisheries Service, Stephen Bortone 

 of the University of West Florida, and Michael J. Van 

 Den Avyle of the University of Georgia for their critical 

 reviews of the original manuscript. I would like to 

 thank Drs. Allyn G. Johnson and J. Jeffery Isely of the 

 National Marine Fisheries Service for assistance in 

 reading structures and guidance in statistical analysis. 



Citations 



Backus, R.A. 



1962 Age in a small sample ul' hluel'ish {PditKiloniiia salliilrix 

 Linneaus). Breviora l.'i9:l-4. 

 Briggs, J.C. 



1960 Fishes of worldwide (circumtropical) distriliution. Copeia 

 1960:171-180. 

 Fable. W.A. Jr.. H.A. Brusher. L. Trent, and J. P'innegan Jr. 

 1981 Fos.sible temperature effects on charter Ixi.-it catclies of 

 king mackerel and other coastal pelagic species in northwest 

 Florida. Mar. Fish. Rev. 43(8):21-26. 

 Hamer, P.E. 



1959 Age and growth studies of the bluefish (Pomaloynus 

 saltatrii Linnaeus) of the New York Bight. M.S. thesis, 

 Rutgers Univ.. New Brunswick. N.I, 27 p. 



