size range have the morphological and pigmentary 

 features of pelagic juveniles. This is also true for S. 

 marinus. Pelagic juveniles remain in the surface waters; 

 they appear to form schools soon after transformation 

 and are particularly susceptible to dip netting under 

 nightlights. Juveniles in the 30- to 50-mm size range are 

 commonly dip netted and a 62.8-mm specimen was 

 taken by this method (Table 12). 



Larvae of S. jordani are the most slender of all 

 Sebastes yet described. Body depth averages 17% of the 

 body length before notochord flexion, 21% during flexion, 

 and 23.5% following flexion. Pelagic juveniles 28 to 68 

 mm long appear to be slightly more slender, with a mean 

 of 22%. 



The rounded pectoral fins are the shortest of any 

 eastern Pacific rockfish larvae yet described. Pectoral fin 

 length averages 7% of the body length prior to notochord 

 flexion and 8% during flexion. This percentage increases 



Table 12. Measurements (nw) of larvae of Sebastes jordani . (Specimens between 

 dashed lines are undergoing notochord fleidon.} 



•Pelagic juvenile. 



gradually following notochord flexion from 11% im- 

 mediately after flexion to 20% in the largest larvae. 

 There is only a slight increase in relative pectoral fm 

 length during the pelagic juvenile stage, up to 22% in the 

 largest specimen available (62.8 mm). The small pec- 

 torals in S. jordani and the ontogenetic changes in 

 relative size agree closely with the condition in the lar- 

 vae of the S. marinus group. The sequence of ossification 

 of the pectorals and other fins is shown in Table 13. 



A character which separates adults and juveniles of S. 

 jordani from all other known species of Sebastes is the 

 anterior placement of the anus. In his key Phillips (1957) 

 indicated that the distance between the anus and the 

 first anal spine in S. jordani is 1.1 to 1.5 orbit diameters, 

 whereas this distance is 0.1 to 0.8 orbit diameters in other 

 species. This wide space between the anus and the anal 

 fin origin is conspicuous in pelagic juveniles and is a 

 useful character in identifying all but the smallest lar- 

 vae. Snout-anus distance averages 36% of the body 

 length in the larvae prior to notochord flexion, 42% dur- 

 ing flexion, and 51% following flexion. In pelagic 

 juveniles it is 54%. Comparative mean percentages for 

 larvae of S. paucispinis are 41 before flexion, 45 during 

 flexion, and 59 following flexion. For larvae of 5. mac- 

 donaldi, the percentages are 42, 52, and 60. 



The pigment pattern of early S. jordani larvae is 

 similar to that of the S. marinus group in the Atlantic. 

 Newborn larvae have the melanistic shield over the gut, 

 a group of melanophores above the brain, and a series of 

 melanophores along the dorsal and ventral midlines of 

 the tail. The ventral row begins at the 3rd to 5th postanal 

 myomere and extends to the 14th and 16th postanal 

 myomere. Typically, in the anterior two-thirds of the 

 series, the melanophores are positioned singly, but in the 

 jTOsterior two-thirds the melanophores are in two ir- 

 regular rows along the ventral midline. For 15 specimens 

 counted, the total number in the ventral row ranged from 

 21 to 27 with a mean of 23.7 ± 1.75 SD. The dorsal row is 

 considerably shorter, beginning at the 7th to 12th 

 postanal myomere and extending posteriad to the 14th to 

 16th myomere. The melanophores are bunched together 

 in an irregular row that contains a mean of 18.9 ± 4.64 

 melanophores (range of 13 to 28) for 18 larvae counted. 



Table 13. Meristics from cleared and stained larvae of Sebastes jordani . 



20 



