California Sea Grant College Program

I investigated the movements of the olive rockfish, Sebastes serranoides, off Santa Barbara, California, using both mechanical and parasite tags. Movements were very restricted over shallow reefs though somewhat less so around deeper oil platforms. Limited movements may contribute to over fishing, as comparisons of olive rockfish size frequencies between two reefs indicates that fishing pressure has reduced olive rockfish populations to almost all prereproductive individuals on the more heavily fished site. I discuss movements of other rockfish and suggest potential management problems and solutions.

Age and growth relations, reproduction and food habits of the olive rockfish were also studied. Olive rockfish grew at a faster rate off Avila than Santa Barbara. Evidence from laboratory studies indicate this differential may be due to ambient temperature. Females grew at a faster rate and attained a larger maximum size than males. Off Avila, spawning took place from December through March. Off Avila, fish mature between 4 and 8 years of age (total length 28-39 cm TL). Olive rockfish feed primarily on midwater nekton during both day and night, though nocturnal benthic feeding (on octopi) becomes increasingly important in larger individuals.