LAROCHE ET AL.: CARANGIDAE 



517 





Fig. 273. Late postflexion larvae oi (\) Elagatis bipinnulata (1 1.4 mm); (B) Oligoplites saurus (8.6 mm) and (C) Seriola zonata (9.5 mm) 



yolk sac, ventral to the head, are the most outstanding characters 

 of yolk sac larvae. The mouth is not formed, and the gut is 

 undeveloped. Eyes lack melanistic pigmentation; fins are un- 

 developed; the notochord is straight; and head spines are lacking 

 (Ahlstrom and Ball, 1954; Aprieto, 1974; Miller and Sumida, 

 1974). The present state of knowledge is not adequate to estab- 

 lish a set of characters which will distinguish pre-fin formation 

 carangid larvae from larvae of all other marine fish families in 

 the world. Newly hatched carangid larvae are difficult to identify 

 even to family due to the paucity of diagnostic morphological 

 characters and multitude of perciform taxa which co-occur and 

 have similar-appearing larvae. Since larvae of many taxa remain 

 unknown, the problem is even more complicated. However, 

 within restricted and well-defined geographic areas it may be 

 possible to define such a character set if the fish fauna is well 

 known (Laroche et al., MS). 



Following yolk absorption, larval carangids range from rel- 

 atively slender forms, i.e., body depth (BD) 20 to 27% SL in 

 Oligoplites saurus (Fig. 273B), to relatively deep bodied forms, 

 i.e., BD 32 to 59% SL in Selene sp. (Aprieto, 1974) (Fig. 274A). 

 The gut develops as a narrow straight tube on the first day after 

 hatching. A single gut loop is present in larvae 3-4 mm NL, 

 which is about 5 days after hatching in Atule mate and Oligo- 

 plites saurus (Aprieto, 1974; Miller and Sumida, 1974). This 

 pattern seems to be common among other species although 

 lengths at which the gut loops vary slightly. The gut extends to 

 midbody with snout to anus length in preflexion and flexion 

 larvae usually ranging from 46 to 67% SL (Aprieto, 1974; Lar- 

 oche et al., MS). The head ranges in length from about 24 to 

 41% SL and is typically about 33% SL. 



Head spines form relatively early in development. The first 

 head spine to develop is a preopercular spine at the angle of the 



