210 



FISHERY BULLETIN OP THE FISH AND WILDLIFE SERVICE 



has a relative depth of about 30-40% S.L. By 

 100 to 140 mm., depth has increased to about 

 60-68% S.L. Relative depth decreases at sizes 

 above about 140 mm. and is less than 60% S.L. 

 at about 200 mm. (appendix table 2 and fig. 20). 

 In Trachinotus sp., depths of the 3.07-, 4.0-, 

 and 4.66-mm. specimens are 18.2, 19.2, and 20.2% 

 S.L., respectively (appendix table 2). 



DORSAL FIN 

 Elements 



Trachinotus sp. — At 3.07 mm., no spines or 

 soft-rays are discernible. At 4.0 mm., five spines 

 and about seven soft-ray buds are barely discern- 

 ible. At 4.66 mm., six spines and 20 soft-ray 

 buds are present (figs. 1-3). 



T. caroKnMs— Elements V to VI-I, 22 to 27. 

 Ginsburg (1952) found that of 346 specimens he 

 examined 51 had six (V-I) and 295 had seven 

 (VI-I) spines; and that of 342 specimens examined 

 36 had 23 soft-rays, 183 had 24, 110 had 25, 12 

 had 26, and 1 had 27. Of 197 specimens examined 

 in my study, 17 had six dorsal spines, and 180 

 had seven. Dorsal soft-ray counts were made 

 on 172 specimens: One had 22, 12 had 23, 99 

 had 24, 55 had 25, and 5 had 26 dorsal soft-rays 

 (table 1). Spines are prominent, and soft-rays 

 are developed by about 7 mm. (fig. 4). At this 

 size all but about six of the soft-rays are seg- 

 mented; none is branched. All soft-rays are 

 segmented by about 10 mm. Branching occurs 

 at about 18-20 mm. in all soft-raj's except the 

 first (anteriormost), which branches at approxi- 

 mately 40 mm. 



T. /aZca<Ms.— Elements VI-I, 17 to 21. Gins- 

 burg (1952) examined 24 specimens and found 

 aU to have seven dorsal spines. One specimen 

 had 18 dorsal soft-rays, 16 had 19, and 7 had 20. 

 All 386 specimens examined for this character 

 in my study had seven (VI-I) dorsal spines. One 

 specimen had 17 soft-rays, 13 had 18, 255 had 

 19, 113 had 20, and 4 had 21 (table 2). Spines 

 are prominent in the 5.0-mm. specimen (fig. 8), 

 and the individual soft-rays discernible. No 

 segmentation or branching has occurred. By 

 about 6.5 to 9 mm. all but 1 to 3 soft-rays have 

 segmented. All are segmented after about 9.5 

 mm. Branching begins at about 12 mm., and 

 all soft-rays except the first are branched by 

 about 17 mm. Branching is completed by about 

 20 to 24 mm. 



Table 1. — Dorsal and anal soft-ray relation for 172 speci- 

 mens of Trachinotus carolinus 



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

 nation; numbers in parentheses represent approximate percentage of the 

 sample with that combination] 



Table 2. — Dorsal and anal soft-ray relation for SS6 speci- 

 mens of Trachinotus falcatus 



lUpper numbers in blocks represent specimens with the indicated combi- 

 nation; numbers in parentheses represent approximate percentage of thfl 

 sample with that combination] 



T. glaii€us.— Elements VI-I, 19 or 20. AU 39 

 specimens examined by Ginsburg (1952) had 

 seven dorsal spines; 23 had 19 soft-rays and 16 

 had 20. All 74 specimens I examined had seven 

 (VI-I) dorsal spines; 45 had 19 soft-rays and 29 

 had 20 (table 3). In the 7.8-mm. specimen (fig 

 14) all soft-rays but the anteriormost and the 

 last three are segmented. Segmentation is com- 

 plete in the 11.8-mm. specimen (fig. 15). Branch- 

 ing has not begun by about 19 mm.; but all 

 soft-rays except the first are branched by about 

 23 mm., and the first soft-ray branches between 

 28 and 35 mm. 

 Lengths 



The dorsal fin possesses no lobe at sizes smaller 

 than about 11 mm.; i.e., the anterior distal margin 



