GRISWOLD and McKENNEY: LARVAL DEVELOPMENT OF SCUP 



stained as are the pterygiophores. The hypural plates 

 are all present and completely ossified; a few dorsal 

 plates are still partially cartilaginous. 



By the time scup are 18-19 mm long, they are 

 juveniles. Ossification continues in the skull with the 

 bones being joined at suture points; the pelvic girdle 

 is complete. The pterygiophores and ribs have com- 

 pleted ossification. 



PREOPERCULAR SPINES 



Figure 2 shows the development of preopercular 

 spines. We saw them first on a 4.1 mm specimen, 

 which has three spines on the preopercular margin. 

 Thereafter their number increases until there are so 

 many on a 16.9 mm specimen that the margin is 

 serrate. Specimens larger than about 25 mm have 

 nearly smooth preopercular margins. 



and Schroeder 1928) placed S. aculeatus in the 

 synonomy of S. chrysops; Robins et al. (1980) did not 

 list S. aculeatus. Dahlberg (1975) mentioned young 

 stages of S. chrysops with crossbars (i.e., juveniles) in 

 his account of Georgia coastal fishes, although it is 

 not clear whether he had taken such specimens in 

 his collections. 



This issue is further complicated by lack of informa- 

 tion about the northern extent of spawning of other 

 sparid fishes. If their spawning ranges overlap with 

 that of S. chrysops, then the younger larvae of some 

 species will probably be confused with scup larvae, at 

 least until the dorsal, anal, and pectoral fin rays can 

 be counted. Except for the reference to juvenile scup 

 on the Georgia coast by Dahlberg, the authors can 

 find no references to such an overlap. 



We have seen larval scup in collections misiden- 

 tified as Scomber scombrus, the Atlantic mackerel, 

 from which they can be separated at all stages by the 

 numbers of myomeres (24 in scup and 31 in mack- 

 erel). We have also seen larval gerreid fishes misiden- 

 tified as scup. Among other characters, scup differ 

 from gerreid fishes in lacking the long premaxillary 

 spines that extend up between the eyes in gerreids. 



Figure 2.— Development of the preopercular spines of Stenotomus 

 chrysops. Standard lengths in millimeters of the specimens are A) 

 4.1, B) 5.6, C) 8.3, D) 9.8, and E) 16.9. 



ACKNOWLEDGMENTS 



We are grateful to John Colton, Bernard Skud, 

 Donna Busch, Wallace Smith, and Michael Fahay for 

 their reviews of the manuscript. We thank Jennie 

 Dunnington and Maureen Montone for typing and 

 retyping the manuscript. We are particularly indebt- 

 ed to Lianne Armstrong who prepared Figure 1 and 

 Alyce Wells for help with Figure 2. 



SCALES 



The first scales are seen between 9.9 and 10.8 mm. 

 At 12.3-13.0 mm the larvae are completely scaled. 



COMPARISONS 



The geographical extent of spawning of S. chrysops 

 is not known. The authors can find no record of it 

 spawning south of the New York Bight. At least one 

 other species of Stenotomus, S. caprinus (Bean 

 1882), occurs in the western North Atlantic. Accord- 

 ing to Geohagen and Chittenden (1982), the major 

 population of this species is in the northern Gulf of 

 Mexico and it occurs only rarely along the east coast 

 to North Carolina. A third nominal species, S. aculeatus 

 (Valenciennes 1830), said to replace S. chrysops 

 south of Cape Hatteras, is of doubtful validity. 

 Birdsong and Musik (in 1977 reprint of Hildebrand 



LITERATURE CITED 



BlGELOW, H. B., AND W. C. SCHROEDER. 



1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Serv., 

 Fish. Bull. 53, 577 p. 

 Bremer, C. ML, Jr 



1948. Field book of marine fishes of the Atlantic coast from 

 Labrador to Texas. G. P. Putnam's Sons, N.Y., 349 p. 

 Dahlberg, M. D. 



1975. Guide to coastal fishes of Georgia and nearby 

 states. Univ. Georgia Press, Athens, 186 p. 

 Geohagen, P., and M. E. Chittenden, Jr. 



1982. Reproduction, movements, and population dynamics 

 of the longspine progy, Stenotomus caprinus. Fish. Bull., 

 U.S. 80:523-540. 

 Herman, S. S. 



1963. Planktonic fish eggs and larvae of Narragansett 

 Bay. Limnol. Oceanogr. 8:103-109. 

 Hildebrand, S. F., and W. C. Schroeder. 



1928. Fishes of Chesapeake Bay. T. F. H. Publications, Inc., 

 Neptune, N.J., 388 p. (1 972 reprint with comments by R. 

 S. Birdson and J. S. Musik.] 



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