LAROCHE and MCHARDSON: DEVELOPMENT OF LARVAE AND JUVENILES OF ROCKFISHES 



tips of the preocular spine weakly present. Hitz 

 (1965) indicated that only the preocular spine is 

 present. Hart (1973) stated that head spines are 

 absent or weakly present, represented by the tip of 

 the preocular spine. The original description of S. 

 mystinus i Jordan and Gilbert 1881) stated that the 

 "top of head" is without spines, with the exception 

 of a very small nasal spine and sometimes a 

 preocular spine present. Phillips (1957) and Hitz 

 (1965) also reported this spine pattern. Miller and 

 Lea's (1972) key to the rockfishes of California 

 placed S. mystinus in the category of having head 

 spines "weak or obsolete." Hart (1973) reported 

 nasal and "... occasionally minute preopercular 

 [sic = preocular] spines present" with other spines 

 usually obsolete. 



Supraorbital spines are small even in juveniles 

 and have often been overlooked on S. entomelas 

 and S. mystinus. We found that preocular, su- 

 praocular, postocular, and tympanic spines are 

 usually present in both S. entomelas and 

 S. mystinus, although the first two spines may 

 be absent on one side of the head. The only excep- 

 tion observed was one juvenile S. mystinus which 

 lacked both preocular spines. These spines even- 

 tually become overgrown by scales, tissue, and 

 bone but using a dissecting microscope they are 

 visible on all specimens examined including 

 adults to 342 mm. However, scales and tissue 

 must first be probed away before observation in 

 S. mystinus >150 mm. In S. entomelas (115 pelagic 

 juveniles, 49-78 mm) from Oregon, 4% lacked one 

 preocular spine and 47c lacked one supraocular 

 spine. In S. mystinus (135 pelagic juveniles, 

 51-71 mm) from Oregon, 6% lacked one preocular 

 spine, and no specimen lacked a supraocular spine. 



During our previous study of S. flavidus and S. 

 melanops (Laroche and Richardson 1980) some 

 variation in supraorbital head spine patterns (i.e., 

 occasional presence of preocular and supraocular 

 spines) was observed which could potentially 



cause confusion with S. entomelas. Although simi- 

 lar, S. mystinus has distinctive fin and scale counts 

 (Laroche and Richardson 1980). Because we 

 lacked material to quantify the spine variations, 

 we excluded any variants (i.e., any specimens hav- 

 ing preocular or supraocular spines) from the S. 

 flavidus and S. melanops selected for the devel- 

 opmental series to insure positive identification. 

 New data quantifying spine pattern variation in 

 juveniles of these two species are presented here 

 (Table 8). Presence of a preocular spine is quite 

 rare but occurrence of a supraocular spine is more 

 variable particularly in specimens from Oregon. 

 Separation of S. entomelas from these two species 

 is still possible for most specimens based on pres- 

 ence or absence of the preocular spine since >96% 

 of S. entomelas and <2% of S. flavidus and S. 

 melanops have one. Scale and fin ray counts 

 further distinguish these species as described by 

 Laroche and Richardson (1980). 



ACKNOWLEDGMENTS 



We wish to thank the followdng people for pro- 

 viding specimens for examination: William Barss, 

 Carl Bond, Tina Eschevera, William Eschmeyer, 

 Wendy Gabriel, Gary Hettman, Michael Hosie, 

 Howard Jones, Earl Krygier, Robert Lea, Jerry 

 Lucas, Lawrence Moulton, William Pearcy, and 

 Jose Sepulveda-Vidal. Special thanks are ex- 

 tended to William G. Pearcy for allowing us to use 

 his extensive midwater trawl collections from 

 waters off Oregon and to Joan Newman for typing 

 the tables and somehow maintaining good humor. 



LITERATURE CITED 



EFREMENKO, V N., AND L. A. LISOVENKO. 



1970. Morphological features of intraovarian and pelagic 

 larvae of some Sebastodes species inhabiting the Gulf of 

 Alaska. In P A. Moiseev (editor), Soviet fisheries inves- 

 tigations in the northeast Pacific. Part V, p. 267-286. 



Table 8. — Percentage occurrence of preocular Eind supraocular spines in juvenile Sebastes flavidus and S. melanops. 



Species 



flavidus: 



'Bntish Columbia (W = 37;42-56 mm) 

 ^Oregon (offshore) (N = 72;47-59 mm) 

 . melanops 



'British Columbia (N = 98:45-66 mm) 

 ^Oregon (offshore) (W = 105;43-60 mm) 

 'Oregon (tidepools) (/V = 101;43-60mm) 

 'California (tidepools) (W = 80:41-53 mm) 



'Benthic juveniles. 

 ^Pelagic juveniles. 



255 



