Figure 16.— Stations in the Gulf of 

 California at which larvae of 

 Seba»tes Gulf of California Type A 

 were taken on CalCOFI cruises 

 during 1956 and 1957. 



Table 20. Measurerrents (run) of larvae of Sebastes marlmjs. (Spetlmens between dashed lines 

 are undergoing notochord flexion.) 



•Peljiglc juvenile. 



The larvae are more slender than all but the slen- 

 derest of eastern Pacific Sebastes, such as S. jordani, 

 which they resemble in a number of other characters. 



Body depth averaged 18% of body length in preflexion 

 larvae, 21% during flexion, and 25% in postflexion larvae 

 and early pelagic juveniles. 



The gut is compact and relatively shorter than most 

 eastern Pacific Sebastes. In larvae less than 10 mm, the 

 relative snout-anus length is equal to or less than in 

 Sebastes jordani (Fig. 18). In developmental stages 

 larger than this, relative snout-anus length is inter- 

 mediate between S. jordani and the other eastern Pacific 

 species measured. Snout-anus distance increases from an 

 average of 35% of body length in preflexion larvae to 45% 

 during notochord flexion, and further to 58% in post- 

 flexion larvae and small pelagic juveniles. 



The head is relatively small as in other species of 

 Sebastes. Head length averages 21% of the body length in 

 preflexion larvae, 29% in larvae undergoing flexion, and 

 32% in postflexion larvae and small pelagic juveniles. 

 Snout length averages 28% of head length in preflexion 

 larvae, increases to an average of 31% in later larval 

 stages, and then decreases slightly to an average of 29% 

 in small pelagic juveniles. Relative eye diameter is 

 greatest in preflexion larvae (mean of 40% of head 

 length) and then decreases to a mean of 35% of head 

 length in later developmental stages. 



A prominent feature of S. marinus larvae is their 

 relatively short rounded pectoral fins. Fin length 

 averages 6% of body length before notochord flexion, 10% 

 during flexion, 17% in postflexion larvae, and 22% in 

 small juveniles. Relative fin length is less than in all 

 eastern Pacific species studied with the exception of S. 

 jordani which has similarly small pectorals (Fig. 19). 

 Pelagic juveniles of S. marinus have a slightly longer pec- 

 toral fin than in pelagic juveniles of S. jordani (Fig. 19). 

 The sequence of ossification of the pectorals and other 

 fins could not be determined because of calcium leaching 

 in the Formalin-preserved specimens. 



The pigment pattern of S. marinus larvae is similar to 

 that of other North Atlantic Sebastes species and is also 

 similar to that of S. jordani of the eastern Pacific. New- 

 born larvae have a group of melanophores above the op- 

 tic lobes of the brain, a melanistic shield over the dor- 

 solateral surface of the gut, an embedded spot at the 

 nape, and a series of melanophores along the ventral and 

 dorsal midlines of the tail. The ventral row begins at the 

 4th to 7th postanal myomere and extends to the 19th to 

 22nd postanal myomere. In a sample of 18 full-term in- 

 traovarian larvae, the total number of melanophores in 

 the ventral row ranged from 11 to 24 with a mean of 



18.0 ± 4.07 SD. The dorsal row is shorter, beginning on 

 the 10th to 15th postanal myomere and ending on the 

 18th to 22nd postanal myomere; the number of 

 melanophores ranged from 8 to 21, with a mean of 



13.1 ± 3.16 for the 18 specimens. 



The ventral midline series of S. marinus is shorter and 

 contains fewer melanophores than in larvae of the other 

 North Atlantic species and in S. jordani of the Pacific. In 

 120 newborn specimens of the American form, the num- 

 ber of ventral melanophores ranged from 26 to 42 and in 

 three newborn specimens of S. viviparus from the Faeroe 

 Islands the number ranged from 18 to 29. In 15 specimens 



28 



