DEVELOPMENT OF LARVAE AND JUVENILES OF THE ROCKFISHES 



SEBASTES ENTOMELAS AND 5, ZACENTRUS (FAMILY 



SCORPAENIDAE) AND OCCURRENCE OFF OREGON, WITH NOTES ON 



HEAD SPINES OF S. MYSTINUS, S. FLAVIDUS, AND 5. MELANOPS^ 



Wayne A. Laroche and Sally L. Richardson^ 



ABSTRACT 



Developmental series of larvae and juveniles of two species of northeast Pacific rockfishes (Scor- 

 paenidae: Sebastes^ are described and illustrated: S. entomelas (9.9-74.5 mm standard length) and S. 

 zacentrus ( 7.4-74.8 mm standard length). Descriptions include literature review, identification criteria, 

 distinguishing features, general development, morphology, fin development, spination, scale forma- 

 tion, and pigmentation. 



Ontogeny of S. entomelas is very similar to that of S. flavidus and S. melanops among species for 

 which development is known. All have moderately slender bodies and moderately developed head 

 spines. Pigment patterns develop similarly but pigmentation is less intense inS. entomelas. Larval and 

 juvenile S. entomelas within the size range described are distinguished by presence of preocular and 

 supraocular spines, pectoral fin rays usually 18, dorsal fin rays usually =s8, lateral line pores 52-56, and 

 lack of melanophores at the articulation of dorsal and anal fin rays. Ontogeny of S. zacentrus is rather 

 distinctive among species for which development is known. Larvae and juveniles are relatively deep 

 bodied with large head spines. They are distinguished by presence of preocular and absence of 

 supraocular spines, pectoral fin rays usually 17, dorsal fin rays usually 14, anal fin rays usually 7, 

 lateral line pores 38-48, gill rakers 32-37, and relative lack of pigment. 



Young of S. entomelas were taken March -July and S. zacentrus August- December off Oregon. Larvae 

 of S. zacentrus seemed to have a more restricted offshore distribution than reported for most other 

 species, possibly a function of seasonal wind and current regimes. 



Additional new information concerning variation in supraocular spine patterns is presented as 

 supplemental data to aid in identification and separation of four similar species, S. entomelas, S. 

 flavidus, S. melanops, and S. mystinus. 



The rockfish, Sebastes spp., resources of the north- 

 east Pacific Ocean are being subjected to increas- 

 ing fishing pressure. In 1978, trawl landings of 

 rockfishes (all species) by the United States and 

 Canada were 26,000 metric tons (t) or 38% of total 

 Pacific landings (Pacific Marine Fisheries Com- 

 mission 1964-78). This represents a sizable in- 

 crease in the catch of "other rockfish" from previ- 

 ous years, e.g., 20,100 t in 1978 compared with 

 15,700 1 in 1977 and 9,900 1 in 1976 (Pacific Marine 

 Fisheries Commission 1964-78). Since many rock- 

 fish species are long lived, living over 20 yr (Phil- 

 lips 1964; Westrheim and Harling 1975), overfish- 

 ing could have serious consequences. Rational 



'From a final report for NOAA-NMFS Contract No. 79-ABC- 

 00087 submitted to Northwest and Alaska Fisheries Center, 

 National Marine Fisheries Service, NOAA, 2725 Montlake 

 Boulevard East, Seattle, WA 98112, on 31 July 1979. 



School of Oceanography, Oregon State University, Corvallis, 

 Oreg.; present address: Gulf Coast Research Laboratory, East 

 Beach, Ocean Springs, MS 39564. 



utilization of these important resources requires 

 an understanding of the life history and biology 

 of each species involved. Yet, such information is 

 still lacking for most of the rockfishes. 



This paper provides some of the first informa- 

 tion on the early life history of S. entomelas, 

 widow rockfish, and S. zacentrus, sharpchin rock- 

 fish. Sebastes entomelas was one of five principal 

 species in Oregon bottom trawl landings of "other 

 rockfish," composing 13% of the catch during the 

 years 1963-71, although annual catches fluctuated 

 from 168 to 1,074 t (Niska 1976). Introduction of 

 midwater trawl fishing for rockfish has recently 

 focused attention on S. entomelas since large 

 catches have been landed, e.g., during a 4-mo 

 period in 1979 >90% of the 909 1 of rockfish landed 

 in Oregon were S. entomelas (Barss^). Sebastes 



^William Barss, Fishery Biologist, Oregon Department of Fish 

 and Wildlife, Marine Science Drive, Newport, OR 97365, pers. 

 commun. July 1979. 



Manuscnpt accepted December 1980. 

 FISHERY BULLETIN: VOL. 79. NO. 2, 1981. 



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