<em>Abstract.</em>—San Francisco Bay provides spawning and rearing habitat for California’s largest population of Pacific herring <em>Clupea pallasi</em>. This population provides a food source for other species and supports a valuable fishery for Pacific herring roe. Since the inception of the roe fishery in 1973, the California Department of Fish and Game has conducted annual surveys of spawning in San Francisco Bay as part of an ongoing assessment of population status and management of the fishery. The purpose of this paper is to document (1) regions of San Francisco Bay used by Pacific herring as spawning grounds over time, and (2) time periods in which spawning took place. Spawn data were analyzed by geographic region in the bay and by month for the period 1973–2000. During this period, we documented 269 spawning events from Point San Pablo south to Redwood City. Estimates of spawning adult biomass (fish that were not harvested by the fishery) ranged from 80,813 metric tons in 1981–1982 to 3,199 metric tons in 1997– 1998 (mean = 34,688 ± 19,325 SD). January was the peak spawning month, followed by December and February; small variations in this pattern occurred during some years. Overall, the majority of spawning took place in the north-central bay region (Point Bonita to Richmond-San Rafael Bridge, Angel Island, Point San Pablo, Berkeley flats; 55%) and the San Francisco region (Golden Gate Bridge to Candlestick Point; 34%), although it alternated between these two regions over time. In some years, considerable spawning took place in the Oakland–Alameda region (San Francisco–Oakland Bay Bridge to Bay Farm Island). The largest spawns and peak periods of spawning may not contribute most toward the next generation of Pacific herring, due to differential mortality within the season. For this reason, all regions documented in this study are important spawning grounds for Pacific herring from November through March each year. A number of recent studies have furthered our understanding of Pacific herring early life history and the forces that drive year-class formation in San Francisco Bay. However, studies are especially needed that will improve our ability to adequately address the potential impacts of human activities on Pacific herring in this highly urbanized estuary.
The ecology of a predaceous troglobitic beetle, Neaphaenops tellkampfii (Coleoptera: Carabidae, Trechinae) I. Seasonality of food input and early life history stages
