UC San Diego Library – Scripps Digital Collection

The California Department of Fish and Game has conducted periodic studies on Pacific herring since 1953. This report concentrates on the period from 1972 through 1980 during which the herring fishery underwent a dramatic resurgence due to the opening of a lucrative market for herring roe in Japan. The spawning biomass of Pacific herring was estimated by determining numbers of eggs spawned and using previously derived estimates of eggs per gram of fish to convert this figure to short tons of herring. Spawning biomass estimates for Tomales Bay ranged from 4,728 tons in the 1974–75 season to 22,163 tons in the 1977–78 season. Estimates for San Francisco Bay ranged from 6,179 tons in 1973–74 season to 52,869 tons in the 1979–80 season. Sampling the roe fishery catch in Tomales and San Francisco Bays revealed that age 2 and 3 herring dominated the round haul fishery, and ages 5 and 6 dominated the gill net fishery. Gill nets consistently caught larger herring and a higher percentage of females than round haul nets. Comparison of length at age of herring from Tomales and San Francisco Bays revealed a statistical difference in growth rates between populations of the two bays. Tomales Bay herring are larger at a given age than San Francisco Bay herring. Spawning time was related to the tidal cycle in San Francisco Bay. From 1973 through 1976, 88% of all spawnings occurred when the daily high tide was at night. The resurgence of the fishery and evolution of current management strategies of quotas, seasons, and resource monitoring are discussed.