FISHERY BULLETIN: VOL. 70, NO. 3 



Figure 2. — Planktonic larvae of Sebastes macdonaldi from CalCOFI plankton samples. A. 11.2 mm; B. 15.9 mm. 



sal juveniles (Figure 4) and in adults, its pos- 

 terior end extends to below the posterior margin 

 of the orbit. The relative length of the snout 

 does not change markedly during the larval pe- 

 riod; snout length averages 32 /f of the head 

 length throughout the larval period. In pelagic 

 juveniles snout length is redured slightly to an 

 average of 28 7r of the head length. Likewise, 

 the width of the interorbital region changes 

 little relative to head length in larvae; it aver- 

 ages about 46 /V of the head length. At the end 

 of the larval period the interorbital distance be- 

 comes markedly narrower and averages 27% of 

 the head length in pelagic juveniles. Similar 

 changes in relative growth rate of the head, eyes, 

 jaws, snout, and interorbital region occur in 

 larvae and early juveniles of S. pmicispinis. 



FIN DEVELOPMENT 



The pectoral fins begin to form during em- 

 bryogenesis and, at parturition, the muscular 

 base of each fin is distinct from the fan-shaped 

 future rayed portion. The rayed portion en- 

 larges considerably during early planktonic life 

 and becomes covered solidly with melanophores 

 (Figure IB) . The rays begin to ossify in larvae 

 as small as 6.3 mm (Table 2) ; ossification begins 

 with the most dorsal rays and then proceeds ven- 

 trad sequentially. Larvae 19.2 mm and larger 

 have the full complement of 19 stained pectoral 

 rays. The pectoral fins elongate slowly and grad- 

 ually and have a short stubby appearance 

 during most of the larval period. The length 

 of the rayed portion of the fin averages 8% of 



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