ABSTRACT 



The young of five species of jack crevalles (Caranx) commonly occur off the 

 Atlantic coast of the United States: Caranx crysos, C. ruber, C. bartholomaei, 

 C. latus, and C. hippos. Morphometric, meristic, and morphological characters, 

 and serial illustrations are presented for each of these species from the smallest 

 larval or early juvenile sizes available into the better-known juvenile and adult 

 stages. Development of certain body parts is defined and discussed, and com- 

 parisons are made for the species. The smallest available specimens of C. 

 dentex and C. lugubris — species which occur in the Western Atlantic, but have 

 not been reliably reported from inshore waters of the United States — are briefly- 

 compared with the five common species. Nomenclatorial problems are dis- 

 cussed; several identification and distribution records are corrected; and a key 

 to the seven species is given. 



Apparently the five common species have an offshore larval existence. Off 

 the southeastern Atlantic coast of the United States the larval stage occurs in 

 association with the offshore waters of the Gulf Stream. C. latus and C. hippos 

 lose their preopercular spines (a larval character persisting into the juvenile 

 stage) at about 20 mm standard length — at a smaller body size than occurs 

 in the other three common species — and they tend to migrate inshore at about 

 this size. C. crysos, the relatively most-abundant young Caranx in this area, 

 apparently does not migrate inshore before its late juvenile stage; C. bartholomaei 

 occurs inshore only occasionally as a juvenile or adult; and C. ruber has an 

 apparent tendency to remain offshore. As late juveniles or adults, all these 

 species may return to more southern areas. 



The following suppositions are made regarding spawning of the five common 

 species: Spawning tends to occur in offshore waters, at least partially in associ- 

 ation with major current systems, and extends from about February into Sep- 

 tember. C. bartholomaei probably spawns off the southeastern Atlantic coast 

 of the United States, and the other four common species do spawn there; but 

 the major spawning areas for these species are to the south of this area. 



The time and place of spawning and the larval and early juvenile forms are 

 unknown for C. dentex and C. lugubris. Their juvenile and adult habitats are 

 apparently in offshore waters and in association with offshore islands. 



The smallest, definitely identified specimens available for study were, in 

 standard length, C. crysos, 5.4 mm.; C. ruber, 12.4 mm.; C. bartholomaei, 8.1 mm.; 

 C. latus, 16.1 mm.; C. hippos, 15.3 mm.; C. dentex, 87 mm.; and C. lugubris, 

 242 mm. A series of specimens, 5.4 to 8.3 mm., identified only as Caranx sp. 

 {"latus and/or hippos") includes either one or both of these species. 



The affinity of Hemicaranx fasciatus (Cuvier) and Uraspis heidi Fowler 

 to the genus Caranx is briefly discussed. 



