SMITH and DAIBER: BIOLOGY OF SUMMER FLOUNDER 



TABLE 5. — Meristic and morphometric data for summer flounder taken from Delaware 

 Bay in 1966, and ranges reported in the literature that were exceeded. 



'Ginsburg (1952) 



2 Hildebrand and Schroeder (1928). 



3 Deubler (1958). 



"Jordan and Evermann (1898) 



TABLE 6. — A comparison of some summer flounder meristic characters between Delaware Bay ( present 

 study), Chesapeake Bay (Ginsburg 1952), and North Carolina [1 (Deubler 1958), 2 (Ginsburg 1952), and 3 

 (Woolcott et al. 1968)]. 



significant difference at 0.05 level, 

 significant difference at 0.01 level. 



the definitive number of gill rakers is not usually 

 present until summer flounder are 18 mm stan- 

 dard length. Woolcott et al. used fish below this 

 length, and this could account for the significant 

 difference between their counts of lower arch gill 

 rakers and the counts by Ginsburg ( 1952), also for 

 fish from North Carolina. 



Anal fin and gill raker data (Table 6) do suggest, 

 however, that summer flounder from North 

 Carolina belong to a population that is racially 

 different from the population containing 

 Chesapeake Bay and Delaware Bay flounder. This 

 supports Smith's (1973) observation that there is 

 mounting evidence for the existence of separate 

 populations of summer flounder based on: 1) dis- 

 tribution of eggs and larvae, 2) meristic differ- 

 ences, 3) tag returns, and 4) commercial flounder 

 landings. It is possible that separate populations 

 or stocks exist because summer flounder undergo 



fairly rapid development, 74 to 94 h hatching time 

 (Smith 1973), and conditions affecting egg and 

 larval transport may minimize mixing between 

 geographic areas. This possibility is suggested by 

 Chang and Pacheco (1976) even though they 

 assumed a unit stock for their population evalua- 

 tion. There should be more research into the possi- 

 bility of multiple populations before final man- 

 agement recommendations are made. 



ACKNOWLEDGMENTS 



We thank George R. Abbe, Gary W. Schmelz, 

 Raymond C. Wockley, and the boat crew at the 

 Lewes Field Station for all their help in the field. 

 Special thanks go to Henry B. Tingey for help in 

 some statistical analyses; to Earl E. Deubler, Jr., 

 of the University of North Carolina for donating 

 otoliths and data from small summer flounder; 



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