rays differentiate, the melanophores become restricted to 

 the interradial membrane and the distal margin of the 

 pectoral fin develops a melanistic outline. The 7.2-mm 

 larva has added a melanophore above the olfactory lobes, 

 a spot on the ventrum at the juncture of the cleithra, and 

 a covering of melanophores on the pelvic fins. 



The gap in the series between 7.2 and 14.8 mm 

 prevents study of pigment changes in this size range. The 

 14.8- and 19.6-mm specimens are pigmentless except for 

 a wide band of melanophores on the caudal peduncle. In- 

 terestingly, many and possibly all species oi Sebastomus 

 from the northeast Pacific have a caudal peduncle band 

 at this stage. 



Fin counts on the two dip net specimens (dorsal, XIII, 

 13; anal, III, 6; pectoral, 18) fit known meristics for S. 

 capensis. A count of 42 lateral line pores on the 19.6-mm 

 specimen falls within the range for S. capensis. 



Distribution. — Chen (1971) summarized the dis- 

 tributional information on this species. 



Se6a«te8— Northwestern Pacific Species, Figure 22 



Literature. — According to Chen (pers. commun.) 

 there are 31 species of Sebastes in the northwestern Pa- 

 cific. Life history series have been published on eight of 

 these. 



Fujita (1957) reared larvae of S. pachycephalus nig- 

 ricans which had been extruded spontaneously by a cap- 

 tive pregnant female. The larvae were fed brine shrimp 

 nauplii and kept at 16.4° to 18.8°C for 1 mo. The larval 

 series was described and illustrated. 



Fujita (1958) obtained a series of developing embryos 

 of S. oblongus from two pregnant females maintained in 

 an aquarium at 13.5° to 18.0°C. Larvae from one female 

 were reared at 16° to 18°C on a diet of brine shrimp 

 nauplii for 30 days until fin formation was completed. 

 The series of developing embryos and larvae was de- 

 scribed and illustrated. 



Uchida et al. (1958) described and illustrated three 

 specimens of S. hubbsi taken from plankton hauls. 



Shiokawa and Tsukahara (1961) obtained a series of 

 embryos of S. pachycephalus pachycephalus from cap- 

 tive females and then reared the larvae for 25 days at 

 15°C on a diet of brine shrimp nauplii. The embryos and 

 larvae were described and illustrated as were demersal 

 juveniles up to about 25-mm length netted from shallow 

 water. 



Harada (1962) described and illustrated a series of S. 

 inermis that included late preextrusion larvae taken 

 from pregnant females, larvae collected by plankton net, 

 and juveniles up to about 60 mm in length. 



Takai and Fukunaga (1971) followed development of 

 embryos in a captive female of S. longispinus and reared 

 the larvae for 30 days on a diet of brine shrimp and Tig- 

 riopus nauplii. The embryos and larvae were described 

 and illustrated. 



Sasaki (1974) removed late preextrusion larvae from 

 freshly killed females of S. schlegeli, S. steindachneri, 

 and S. taczanowskii. He summarized morphological and 



pigmentary characters of 20 specimens of each species 

 and illustrated a specimen of each. 



Distinguishing features. — Larvae of S. oblongus 

 hatch at a total length of 7.25 mm or 6.5 mm notochord- 

 al length.' This is 1 mm larger than any eastern Pacific 

 species described and slightly less than the range of S. 

 marinus of the Atlantic. The most outstanding feature of 

 S. oblongus larvae is the pattern of melanistic pigment, 

 which begins to form well before hatching. Melanophores 

 first appear as a shield over the dorsal surface of the gut, 

 then patches form on the dorsal surface of the head, on 

 the trunk above the gut, and as a band on the tail. At 

 hatching, melanophores are continuous from the head to 

 the broad tail band and they also appear on the ventral 

 surface of the gut. The pectoral fins are unpigmented. 

 With further development, pigment forms on the 

 preopercular region of the head, along the jaws, the bases 

 of the pectoral fins, and the tail band extends anteriorly 

 and posteriorly. At notochord flexion the larvae are 

 covered with melanophores except for the distal half of 

 the pectoral fin blade and the caudal region (Fig. 22A). 

 Larvae of S. oblongus differ from eastern Pacific and At- 

 lantic species in their extraordinarily heavy pig- 

 mentation and in not developing the series of ventral 

 midline melanophores on the tail. 



Larvae of S. longispinis are spawned at about 5.3 to 5.5 

 mm notochordal length which is equivalent to S. jor- 

 dani. the largest eastern Pacific species at hatching. In- 

 terestingly, the brood of S. longispinis studied by Takai 

 and Fukunaga (1971) hatched as embryos within the 

 ovary at about 3.1 mm notochordal length. Although this 

 may have resulted from stress during captivity, it fur- 

 ther strengthens the view that hatching occurs within the 

 ovary in Sebastes and not after extrusion as stated by 

 some authors (e.g., Morris 1956; Waldron 1968). The 

 development of the pattern of melanistic pigmentation is 

 almost identical to that in S. oblongus (Fig. 22B). The 

 only difference appears to be in the absence of pigment 

 on the distal portion of the pectoral fin base and on the 

 blade of the fin. 



Larvae of S. hubbsi represent a third member of this 

 heavily pigmented group of Japanese Sebastes. The 

 smallest of the three planktonic specimens described by 

 Uchida et al. (1958) was a newborn larva 4.2 mm in 

 notochordal length, indicating that larvae of this species 

 are born at a length 1 mm smaller than larvae of S. 

 longispinis and about 3 mm smaller than S. oblongus. 

 The pigment pattern develops almost identically to that 

 in the other two species, but differs chiefly in the sparse 

 pigmentation of the pectoral fin base and in the develop- 

 ment of evenly distributed minute melanophores on the 

 blade of the pectoral fin (Fig. 22C). 



'It is customary in Japanese descriptions of fish larvae to give body 

 length as total length, including the finfold. Since we use notochordal 

 length in preflexion larvae, the total lengths were converted to notochord- 

 al length by measuring notochordal and total lengths on the illustrations 

 and multiplying the resultant conversion factor by the actual total length 

 given for the specimen. 



36 



