452 



Abstract— A developmental series of 

 larval and pelagic juvenile pygmy 

 rockfish (Sebastes wilsoni) from cen- 

 tral California is illustrated and 

 described. Sebastes wilsoni is a non- 

 commercially. but ecologically, impor- 

 tant rockfish, and the ability to dif- 

 ferentiate its young stages will aid 

 researchers in population abundance 

 studies. Pigment patterns, meristic 

 characters, morphometric measure- 

 ments, and head spination were 

 recorded from specimens that ranged 

 from 8.1 to 34.4 mm in standard 

 length. Larvae were identified ini- 

 tially by meristic characters and the 

 absence of ventral and lateral midline 

 pigment. Pelagic juveniles developed 

 a prominent pigment pattern of three 

 body bars that did not extend to the 

 ventral surface. Species identifica- 

 tion was confirmed subsequently by 

 using mitochondrial sequence data 

 of four representative specimens of 

 various sizes. As determined from the 

 examination of otoliths, the growth 

 rate of larval and pelagic juvenile 

 pygmy rockfish was 0.28 mm/day, 

 which is relatively slow in compari- 

 son to the growth rate of other spe- 

 cies of Sebastes. These data will aid 

 researchers in determining species 

 abundance. 



Description and growth of larval and pelagic 

 juvenile pygmy rockfish (Sebastes wilsoni) 

 (family Sebastidae) 



Thomas E. Laidig 



Keith M. Sakuma 



Santa Cruz Laboratory 



Southwest Fisheries Science Center 



National Marine Fisheries Service, NOAA 



110 Shaffer Rd 



Santa Cruz, California 95060 



E-mail address: torn laidigiS'noaa. gov 



Jason A. Stannard 



La Jolla Laboratory 



Southwest Fisheries Science Center 



National Marine Fisheries Service, NOAA 



P. O. Box 271 



La Jolla, California 92038 



Manuscript submitted 9 -June 2003 

 to Scientific Editor's Office. 



Manuscript approved for publication 



25 February 2004 by the Scientific Editor. 



Fish. Bull. 102:452-463(20041. 



Rockfishes (genus Sebastes) form a 

 diverse group comprising at least 72 

 species occurring in the northeast- 

 ern Pacific (Love et al., 2002). Many 

 of these species represent a substan- 

 tial portion of the groundfish fishery 

 off the west coast of North America, 

 accounting for 20% of the groundfish 

 landings in California in 2000 (Pacific 

 Fishery Management Council, 2000). 

 A few species are relatively abun- 

 dant but are not harvested because 

 of their small size. These species play 

 vital roles in the community ecology, 

 including providing prey for the larger, 

 commercially important species. The 

 pygmy rockfish (Sebastes wilsoni) 

 having a maximum size of 23 cm total 

 length, is among these small species 

 (Love et al., 2002). Pygmy rockfish are 

 common over sediment and rocky sea- 

 floor habitats at a depth of 30-274 m 

 (Stein et al., 1992; Yoklavich et al., 

 2000). Stein et al. (1992) observed 

 that pygmy rockfish were by far the 

 most abundant fish species off Heceta 

 Bank, Oregon, and Love et al. (1996) 

 reported "clouds" of pygmy rockfish 

 mixed with two other small species, 

 squarespot rockfish (S. hopkinsi ) and 

 halfbanded rockfish (S. semicinctus) 

 off southern California. In Soquel 

 Canyon in central California, pygmy 

 rockfish dominated fish assemblages 



in rock-boulder habitat at 75-175 m 

 (Yoklavich et al., 2000). 



Accurate identification of larval 

 stages is critical. Biomass of rock- 

 fish populations can be estimated 

 from larval production (Ralston et 

 al., 2003) and larval and juvenile 

 abundance studies (Moser and But- 

 ler, 1987; Hunter and Lo, 1993 I. If 

 the larval and juvenile rockfish ana- 

 lyzed in these studies are not correct- 

 ly identified, it could lead to either 

 over- or underestimates of biomass 

 or recruitment potential of a popula- 

 tion. Identification of young stages 

 of Sebastes has been accomplished 

 through rearing studies and through 

 descriptions based on developmental 

 series of field-caught specimens of 

 various sizes (Matarese et al., 1989; 

 Moser, 1996). Otolith morphologies 

 have been useful in discerning some 

 Sebastes species (Laidig and Ralston, 

 1995; Stransky, 2001). Recently, mo- 

 lecular methods have proven to be an 

 effective tool for the identification of 

 Sebastes larvae (Seeb and Kendall, 

 1991; Rocha-Olivares, 1998; Rocha- 

 Olivares et al„ 2000). 



In this study, we identify and de- 

 scribe the larvae and pelagic juveniles 

 of pygmy rockfish based on morpho- 

 metries and pigmentation patterns, 

 and estimate age and growth at two 



