226 



Fishery Bulletin 105(2) 



400 450 500 550 500 650 700 



Fork length (mm) 



Figure 15 



First pterygiophore of anal fin in lateral view (outlines traced from radiographs, anterior to left, 

 plotted against fork length) of Pacific crevalle jack (Caranx caninus) (ptergygiophore numbers 

 1-8) and crevalle jack (C. hippos) (9-21). Numbers correspond to those given in Appendix 3 

 where associated catalog numbers, specimen sizes and localities are also provided. 



caught fish, the underside of the caudal peduncle of 

 C. caninus is never bright yellow as in C. hippos, and in 

 fish with uniformly white anal fins the caudal peduncle 

 is also white. 



Remarks We have not had the opportunity to study C. 

 caninus in the field although we have examined many 

 color photographs of recently caught adults. The pro- 

 nounced differences in color of the anal fin in this species 

 (see above) indicate the possibility of sexual dichroma- 

 tism but determining the sex of large Caranx is best 

 done with freshly caught specimens. The striking and 

 inconsistent occurrence of hyperostosis of the third rib 

 in this species (see Table 1) is also puzzling and the 

 possibility that its presence or absence in adults may 

 be sex linked and should be investigated. 



Distribution This species is restricted to the eastern 

 tropical Pacific (Fig. 2), ranging north to San Diego 

 Bay, California, where its occurrence is associated with 

 El Nifio events (Lea and Rosenblatt, 2000), and from 

 Mexico south to Lobos de Tierra Island, Peru (6°27'S); 

 also known from the Galapagos, Malpelo, Cocos, and 

 Revillagigedo islands, but it is unrecorded from Clip- 

 perton Atoll (Robertson and Allen, 1996). Meek and 

 Hildebrand (1925) reported the species, as C. hippos. 

 from tidal streams at Corozal and Balboa, Panama. 



Material examined One hundred ten specimens 

 (59-670 mm FL) from 51 collections. CALIFORNIA; 

 SIO 75-383 (643), San Diego Bay. TRES MARIAS 

 IS.: CAS 216871 (538); MEXICO: ANSP 144417 (25, 

 98-176); ANSP 158506 (4, 248-313); CAS 66825 (155); 

 CAS 11112 (329); CAS-SU 55737 (2, 180-182); CAS 

 216872 (421); SIO 62-61 (3, 372-420); SIO 62-2725 

 (377); SIO 65-176A (670); SIO 65-182 (431); USNM 

 28293 (304); USNM 29556 (152); USNM 29617 (156); 

 USNM 47143 (185); USNM 47144 (213); USNM 

 47145 (191); USNM 100991 (381); USNM 100998 

 (399); USNM 101006 (261); USNM 205166 (307). 

 GUATEMALA: USNM 114469 (8, 77-233); EL SAL- 

 VADOR: ANSP 136539 (172); ANSP 144401 (220); 

 ANSP 144406 (169); USNM 220728 (2, 240-248); 

 USNM 367522 (185); USNM 367542 (156); USNM 

 367671 (81); USNM 367946 (8, 61-77); USNM 367968 

 (63); USNM 367990 (166). PANAMA: ANSP 144409 

 (163); CAS 42539 (333); CAS 66826 (177); CAS 89955 

 (201); USNM 82080 (7, 75-187); USNM 79984 (2, 

 335-348); USNM 128659 (520); USNM 226417 (4, 

 59-112); USNM 321987 (2, 67-84). COLOMBIA: ANSP 

 144413 (164); USNM 206999 (493). ECUADOR: ANSP 

 158998 (137); CAS 66938 (212). GALAPAGOS IS.: 

 USNM 89751 (2, 109-121), Indefatigable Id. PERU: 

 SIO 58-83 (588); USNM 127917 (158); USNM 127918 

 (359); USNM 127919 (360). 



