UC San Diego Library – Scripps Digital Collection

This bulletin presents results of several studies related to marine sportfish in central and northern California. Since 1957, Dingell-Johnson funds have been used in central California to conduct life history studies of blue rockfish and lingcod, several sportfishing assessment studies, a reef ecology study, and a pilot kelp canopy harvesting study. Results of a blue rockfish study were published in 1967, however, important additional life history and catch data have been collected subsequently and a collation of all blue rockfish findings is presented.

Lingcod data have been collated with published lingcod life history data collected in British Columbia and Washington. Our studies emphasized maturity, age and growth, food analyses, and evidence of a vertical spawning migration.

In the reef ecology study, 727 underwater fish transect tallies were made over a 3 year period yielding seasonal variations, relative abundance between stations, and relative abundance between years from 1968 through 1970 of larger species in the kelp bed area.

Pilot kelp harvesting experiments included kelp frond growth and plant life expenctancy, effects of canopy harvesting on haptera growth, kelp standing crop estimates, and effects of canopy removal on kelp bed fish populations.

A thorough literature search of kelp-invertebrate-sea otter interactions was conducted and no valid documentation was found to substantiate reports that the apparent increase in Macrocystis canopy densities since 1958 in central California resulted from sea otter predation on sea urchins.