212 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



most soft-ray does not branch in some specimens 



until about 28 mm. 



Lengths 



The anal-fin lobe becomes discernible at about 

 11 mm. Relative length of the anal-fin lobe 

 increases with increasing standard length to about 

 60 mm. in T. carolinus. A similar increase occurs 

 in T. Jalcatus and T. glaucus and continues 

 throughout all sizes examined, except in large 

 T. jalcatus of 170 to 190 mm., which reach about 

 36% S.L., and in the largest T. glaucus which 

 reach about 67% S.L. At 10-20 mm., anal-fin 

 lobe lengths for T. carolinus, T. Jalcatus, and T. 

 glaucus are about 18-20%, 18-22%, and 22% 

 S.L., respectively, and by about 60 mm. they are 

 about 22-25%, 24-26%, and 23-27% S.L., 

 respectively. T. carolinus maintains a lobe length 

 of 23-26% S.L. to about 280 mm., after which 

 relative length decreases to about 21-24% S.L. 

 (appendix table 2 and fig. 22). 



Relative anal-fin base length increases with 



increasing standard length to about 100 mm. in 



T. carolinus and T. jalcatus. Relative length 



increases in all sizes of T. glaucus, approaching 



43% S.L. at 211 mm. Below 10 mm., base 



lengths for T. carolinus, T. jalcatus, and T. 



glaucus are about 27%, 29%, and 28% S.L. 



respectively, and at about 100 mm., the base 



lengths are about 40%,, 45%o, and 37% S.L. 



T. carolinus and T. jalcatus maintain relative 



anal-base lengths of about 38-42% S.L. and 45- 



47% S.L., respectively, between about 100 and 



280 mm. in T. carolinus, and between about 100 



and 216 mm. in T. jalcatus (appendix table 2 



and fig. 21). 



PECTORAL FIN 

 Elements 



Trachinotus sp. — No spines or soft-rays are 

 evident at 3.07 and 4.0 mm. (figs. 1 and 2). 

 Four or five soft-rays are barely discernible at 

 4.66 mm. (%. 3). 



T. carolinus. — ^Elements I, 16 to 18. Ginsburg 

 (1952) shows the pectoral soft-ray range (compen- 

 sated) as 16 to 18 on 174 specimens; 15 specimens 

 had 16 soft-rays, 130 had 17, and 29 had 18. 

 Of 102 specimens I examined, 14 had 16 soft-rays, 

 75 had 17, and 13 had 18 (table 4). At about 7 

 mm., all but about 4 of the soft-rays are seg- 

 mented and, by about 11 mm., all rays have 

 segmented and branching has probably begun 

 (it is difficult to examine the innermost, or lower- 



most rays in small specimens, therefore error is 

 possible in determining when these soft-rays 

 segment or branch). Branching is complete by 

 about 21 mm. The uppermost ray (adjacent to 

 the spine) remains unbranched. 



T. jalcatus. — Elements I, 17 to 19. La examin- 

 ing 17 specimens, Ginsburg (1952) found two 

 with 17 soft-rays, 14 with 18, and 1 with 19. 

 In 78 specimens I examined, 29 had 17 soft-rays, 

 47 had 18, and 2 had 19 (table 4). At 5.0 mm., 

 the individual rays are discernible, but no seg- 

 menting has occurred. By about 7 mm., all 

 but 4 to 5 soft-rays are segmented and segmen- 

 tation is complete at about 9-12 mm. Branching 

 begins at about 14 mm., and most has occui-red 

 by 20 mm. In some individuals branching is 

 complete by 17 mm., whereas in others it is not 

 complete until about 45 mm. 



Table 4. — Pectoral soft-ray counts for Trachinotus caro- 

 linus, T. falcatus, and T. glaucus 



[Upper numbers in blocks represent specimens with the indicated combi- 

 nation; numbers in parentheses represent approximate percentage of the 

 sample with that combination] 



T. glaucus. — Elements I, 15 to 19. Thirty-six 

 specimens examined by Ginsburg (1952) showed 2 

 specimens with 15 soft-rays, 5 with 16, 24 with 17, 

 and 5 with 18. Of 71 specimens I examined, 1 

 had 15 soft-rays, 8 had 16, 52 had 17, 8 had 18, 

 and 2 had 19 (table 4). All soft-rays are seg- 

 mented by 11.8 mm. and branching has begun by 

 about 16 mm. By about 19 mm., all but 3 to 10 

 soft-rays are branched and branching is complete 

 by 35 to 48 mm. 



Lengths at sizes below 10 mm., T. carolinus 

 and T. jalcatus have pectoral-fin lengths about 

 19% and 13-22%, S.L., respectively. At 10-20 

 mm., T. glaucus and T. jalcatus have reached 

 their maximum relative pectoral-fin lengths of 

 about 25% S.L. Relative pectoral length in- 

 creases in T. carolinus to about 22-25% S.L. at 

 about 70 to 80 mm. (appendix table 2 and fig.23). 

 Relative pectoral-fin lengths are constant above 



