Abstract. — Potential effects of 

 parental stock size and environ- 

 mental factors on year-class 

 strength (YCS) of petrale sole, 

 Eopsettajordani, were investigated 

 in two areas off Oregon and Wash- 

 ington (Pacific States Marine Fish- 

 eries Commission areas 2B: 

 42°50'N^4°18'N, and 3A: 45°46'N- 

 47°20'N). Parental egg production 

 indices and YCS were not consis- 

 tently correlated over the period 

 1970 to 1977. Variation in YCS be- 

 tween 1958 and 1977 was associ- 

 ated with oceanographic conditions 

 from winter to early spring, the pe- 

 riod in which pelagic larval stages 

 are most abundant. A regression 

 model based on indices of offshore 

 Ekman transport from January to 

 March and alongshore transport 

 from December to February ac- 

 counted for nearly 55% of the YCS 

 variation in Area 2B. In Area 3A, 

 the previous two indices plus sea 

 surface temperature from Decem- 

 ber to February explained about 

 65% of the YCS variation. Inshore 

 advection of eggs and larvae could 

 favor settlement of juveniles into 

 nearshore areas and increase the 

 subsequent recruitment strength of 

 petrale sole. 



Environmentally induced 

 recruitment variation in 

 petrale sole, Eopsettajordani 



Gonzalo C. Castillo 

 Hiram W. Li 



Oregon Cooperative Fishery Research Unit, US Fish and Wildlife Service 

 Nash Hall 1 04, Department of Fisheries and Wildlife, 

 Oregon State University, Corvallis, Oregon 97331 



James T. Golden 



Hatfield Marine Science Center. Oregon Department of Fish and Wildlife 

 Building 3, Newport, Oregon 97365 



Manuscript accepted 8 December 1993. 

 Fishery Bulletin 92:481-493 ( 1994). 



Recruitment fluctuations in fish 

 populations are ascribed to many 

 physicochemical factors and biologi- 

 cal processes, including parental 

 stock size and fishing (Ricker, 1975; 

 Shepherd et al., 1984). However, the 

 importance of various factors to the 

 recruitment of most species of fish 

 is virtually unknown. Although 

 year-class strength (YCS) of many 

 fishes is thought to be determined 

 at the egg and larval stages (Sharp 1 ; 

 Rothschild and Rooth, 1982), it may 

 also be significantly affected during 

 the postlarval stages (Smith, 1981; 

 Sissenwine, 1984). 



Increasing evidence suggests that 

 oceanographic conditions affect the 

 recruitment of many fishes in the 

 Northeast Pacific Ocean (e.g. Par- 

 rish et al., 1981; Bailey and Incze, 

 1985; Hollowed et al., 1987; 

 Botsford et al., 1989). A recent hy- 

 pothesis suggests that recruitment 

 of groundfish off the west coast of 

 the United States is related to the 

 timing of the spring transition, a 

 period of major changes in oceano- 

 graphic conditions. 2 On the Or- 

 egon-Washington shelf oceano- 

 graphic conditions exhibit strong 

 seasonal patterns (e.g. Huyer et al., 

 1975; Halpern, 1976; Huyer, 1977; 

 Landry et al., 1989). In winter. 



alongshore currents are northward 

 at all depths, and cross-shore sur- 

 face currents flow inshore resulting 

 in downwelling. In spring, flow is 

 southward at all depths but stron- 

 ger near the surface. The spring 

 transition usually occurs within a 

 one week period during March or 

 April (Strub et al., 1987; Strub and 

 James, 1988). In summer, a surface 

 coastal current flows southwest- 

 ward and the attendant offshore 

 transport causes upwelling; how- 

 ever, deep flow is northward. In fall, 

 alongshore currents are northward 

 at all depths. 



Petrale sole, Eopsetta jordani, 

 Pleuronectidae, is a commercially 

 important flatfish of the northeast 

 Pacific Ocean (Ketchen and For- 

 rester, 1966). It is continuously dis- 

 tributed from the Bering Sea (58°N- 

 152°W) to Baja California (32°26'N- 

 117 16'W) (Roedel, 1953; Hitz and 



1 Sharp, G. D. 1980. Report of the workshop 

 on effects of environmental variation on 

 survival of larval pelagic fishes. In Sharp, 

 G. D. (rapporteur). Report and supporting 

 documentation of the workshop on the 

 effects of environmental variation on the 

 survival of larval pelagic fishes, p. 15-59. 

 Int. Ocean. Comm. Workshop Rep. 28. 



2 Lynn, R. J. Southwest Fisheries Science 

 Center, P.O. Box 271, La Jolla, CA 92038. 

 Personal commun., 1991. 



481 



