Table 3— Observed allelic frequencies (obs. freq.) and number (obs. no.) of alleles 

 at the ldh-2 locus in heart tissue of the dolphin, Coryphaena hippurus. from Miami 

 and Barbados. Expected values (exp. no.) refer to the number expected if the 

 samples do not differ. 



tion observed at ldh-2 did not differ from that 

 predicted under Hardy-Weinberg equilibrium for 

 either population (chi-square goodness of fit: for Bar- 

 bados, x 2 = 6.337, df = 3, 0.25 > P > 0.1; for Miami, 

 X 2 = 9.9145, df = 6, 0.25 > P > 0.1; Table 4). 



The differences in life history traits of Miami and 

 Barbados dolphin could in principle be environmen- 

 tal. The genetic differences observed at the ldh-2 

 locus suggest that there may be little gene flow be- 

 tween the northern and southern groups; but could 

 in theory result from a regional cline. The primary 

 evidence supporting our suggestion of more than one 

 dolphin stock in the western central Atlantic is there- 



Table 4.— The number of each phenotype observed (obs.) 

 at the ldh-2 locus in heart tissue of the dolphin, Coryphaena 

 hippurus, from Barbados and Miami. Expected values (exp.) 

 refer to the numbers expected if the populations are in 

 Hardy-Weinberg equilibrium. 



fore the seasonality of catch data and the mean size 

 of dolphin landed in each territory. Taken together, 

 the three data sets certainly suggest that the 

 assumption of a single stock may be unjustified. Ef- 

 forts should now be made to test the two stock 

 hypothesis proposed and to investigate the possible 

 presence of additional dolphin stocks, particularly 

 in the western Caribbean Sea and in the Gulf of 

 Mexico. 



Acknowledgments 



This project was supported by an Inter-University 

 Council (British Council) grant to Hazel Oxenford, 

 a University of the West Indies research grant to 

 Wayne Hunte and a Manual Noreiga Morales Science 

 Prize from the Organization of American States to 

 Wayne Hunte. The electrophoresis was carried out 

 at the Bedford Institute of Oceanography, Dart- 

 mouth, Nova Scotia, with technical supervision by 

 J. McGlade, and C. Annand, and with technical 

 assistance from D. Beanlands. We thank C. Limouzy 

 for collecting specimens in Miami, R. Mahon for 

 assistance in compiling regional catch records, and 

 J. Horrocks and J. Marsden for comments on the 

 manuscript. Cooperation of fisheries officers and 

 fisheries biologists in the region is gratefully 

 acknowledged. 



Literature Cited 



Allendorf, F. W. 



1979. Rapid loss of duplicate gene expression by natural selec- 

 tion. Heredity 43:247-258. 

 Allendorf, F. W., and F. M. Utter. 



1979. Population genetics. Fish. Physiol. 8:407-454. 

 Bagenal, T. B. 



1971. The interrelation of the size of fish eggs, the date of 

 spawning and the production cycle J. Fish. Biol. 3:207-219. 

 Beardsley, G. L., Jr. 



1967. Age, growth, and reproduction of the dolphin, Cory- 

 phaena hippurus, in the Straits of Florida. Copeia 1967: 



458 



