FISHERY Bl'M-ETIN VOL 77. NO. 1 



General Development. — The smallest larvae of S. 

 pinniger identified, 7.8 mm, are in the final stage 

 of notochord flexion. By the time larvae are 8.8 

 mm long, fle.xion is complete. Transformation to 

 pelagic juvenile begins in larvae -12.5 mm long 

 with the initiation of spine formation in the dorsal 

 and anal fin "prespines" and the appearance of a 

 patch of melanophores on the dorsum immediately 

 posterior to the second dorsal fin. Transformation 

 of the "prespines" to spines is complete in speci- 

 mens > 18.6 mm and some pigment has been added 

 beneath the first dorsal fin marking the beginning 

 of pelagic juvenile pigmentation. The dorsal pig- 

 mentation becomes more pronounced during the 

 pelagic juvenile period which lasts until ~40 to 50 

 mm. The largest pelagic juvenile taken was 42.4 

 mm and the smallest benthic juvenile was 59.4 

 mm. 



Morphology (Tables 4, 8). — Forty-eight specimens 

 of S. pinniger. 7.8 to 181.0 mm long, were mea- 

 sured for developmental morphology. Larvae ap- 

 pear quite deep bodied, but body depth at the pec- 

 toral fin ba.se decreases considerably during the 

 pelagic period from 40 to 33'r SL. In comparison, 

 body depth at the anus/SL changes relatively lit- 

 tle, decreasing slightly then increasing. Snout to 

 anus length increases from 59 to 64'^( SL while 

 snout to pelvic fin distance increases to a lesser 

 degree. 



Head length decreases from 43 to 37*^^ SL during 

 development as more marked changes occur in eye 

 diameter, decreasing from 37-39 to 27'r HL, and 

 interorbital distance, decreasing from 37 to 20Cf 

 HL. Upper jaw length/HL first decreases and then 

 increases while snout length/HL increases then 

 decreases. The length of the angle gill raker in- 

 creases with respect to head length from 1 1 to 14 or 



15'7f. 



Larvae and young juveniles up to 24 mm have a 

 prominent symphyseal knob directed anteroven- 

 trally. It becomes less obvious with development 

 and is barely noticeable by the time juveniles are 

 29 mm long. 



Fin Development (Tables 4, 7, 8). — Pectoral fins 

 are present and the adult complement of 16 to 18 

 (usually 17) rays can be counted in 7.8 mm larvae 

 of S. pinniger. although the ventral rays are not 

 fully formed until >8 mm. The pectoral fins are 

 relatively long in flexion and postflexion larvae 

 averaging 2.5''( SL and they maintain this approx- 

 imate proportion through development. Depth of 



24 



the pectoral fin base decreases from 15 to 9'/f SL. 



Developing pelvic fins are visible on 7.8 mm 

 larvae and the adult complement of I, 5 is count- 

 able in postflexion larvae of 8.8 mm. The pelvic 

 fins are rather long, averaging 14'^f SL in flexion 

 larvae and increasing to a maximum of 23'^f SL in 

 transforming specimens. Length of the pelvic 

 spine, always less than the fin itself, increases 

 from 5^'<- SL in flexion larvae to 2Cf( in transform- 

 ing specimens then decreases to 1.3''f in benthic 

 juveniles. 



The adult complement of principal caudal rays 

 can be counted in 7.8 mm larvae, before the com- 

 pletion of notochord flexion at 8.8 mm. Counts of 

 secondary caudal rays were 11 superior and 12 

 inferior rays on each of two stained juveniles, 29.5 

 and 33.4 mm. 



Bases of some of the dorsal and anal fin ray and 

 spine elements are visible on the 7.8 mm larvae. 

 The adult complement of ray and spine elements is 

 present in postflexion larvae >9 mm and the rays 

 and spines (with "prespines") appear fully formed 

 by 9.3 mm. Transformation of "prespines" to 

 spines is completed by 18.5 mm. The longest dorsal 

 spine increases from 20 to 38'? HL during the 

 pelagic period. The longest dorsal ray increases 

 from 32 to 42 or 439*^ . The longest anal spine in- 

 creases from 19 to 37'7( HL during pelagic de- 

 velopment. 



Spmation (Tables 4, 9). — Spines present on the 

 left side of the head of the two smallest specimens 

 of S. pinniger, 7.8 mm, include the parietal; the 

 nuchal; the first and third anterior preopercular; 

 the second, third, and fourth posterior preopercu- 

 lar; the postocular, the pterotic, the inferior post- 

 temporal; the first spine of the inferior infraorbital 

 series; and the first spine of the superior infraorbi- 

 tal series. 



The parietal spine and ridge are heavily and 

 relatively deeply serrated in small larvae and the 

 spine is relatively long, averaging 24'f HL in flex- 

 ion larvae. Its relative length decreases with de- 

 velopment to 20^7^ HL in flexion larvae, 10^ in 

 transforming specimens, and 77c in early pelagic 

 juveniles, <20 mm. The much smaller nuchal 

 spine averages 4 or 57r HL in postflexion and 

 transforming larvae, decreasing to 19f in benthic 

 juveniles. The parietal and nuchal spines fuse to- 

 gether, beginning in pelagic juveniles -20 mm 

 until only the nuchal tip is visible in juveniles >40 

 mm. Serrations along the parietal ridge can be 

 seen on specimens up to 39 mm. 



