FISHERY BULLETIN: VOL. 79, NO. 3 



Figure 4. — Length-weight relation- 

 ship based on 304 female olive rockfish 

 sampled off Diablo Cove, 1972-77. 



15.0 



20fl 



25.0 



30.0 35£l 



TOTAL LENGTH ICMI 



weight. They increased to 0.9-1.0% (maximum 

 2.2%) of body weight in late fall. It appeared that 

 insemination occurred from October to December, 

 perhaps peaking in November. 



Moser (1967) found "a brood of advanced em- 

 bryos or larvae and a series of ova undergoing 

 vitellogenesis" in S. chlorostictus, S. constellatus, 

 S. eos, S.goodei, S. levis, S. oualis, S . pauc is pints , 

 and S. rosaceus, and stated that this offered direct 

 evidence of multiple brood production. Similar 

 findings for some of the above species were 

 reported by MacGregor (1970), and Miller and 

 Geibel (1973) noted that 1 of 648 S. mystinus 

 examined showed multiple broods. We found no 

 such evidence in olive rockfish, though females 

 usually retained a few unexpelled eyed larvae, 

 which appeared to be resorbed within a few 

 months. 



The evolution of reproductive isolating mech- 

 anisms in the genus Sebastes may not have 



included the restriction of random mating by 

 seasonal isolation. It seems likely that the time 

 from insemination to spawning is similar among 

 closely related species. Rockfish species which 

 mate over the same period, probably spawn at the 

 same time during a later season. Olive rockfish 

 and their presumed subgeneric congeners, .S. 

 flavidus, S. mystinus, and S. melanops, spawn 

 and probably mate during the same seasons 

 (Phillips 1964; Miller and Geibel 1973) as do other 

 closely related rockfish species groups (e.g., S. 

 paucispinis-S. goodei — Moser 1967) and other 

 subgenera {Sebastomus — Chen 1971). 



Instead, habitat isolation among some species 

 (such as S. chrysomelas-S. carnatus — Larson 

 1977) may restrict interspecific mating. However, 

 a number of species pairs (notably S. paucispinis- 

 S. goodei) may aggregate together throughout the 

 year. Even though closely related species mate in 

 the same habitat, during the same season, hybrids 



538 



