Crangon franciscorum
Crangon franciscorum is a species of shrimp in the family Crangonidae which is endemic to the brackish estuaries of California, and found from Puget Sound in the north to San Diego, California in the south. The species is especially abundant in San Francisco Bay, despite population fluctuations due to environmental stresses. Its common names include bay shrimp, sand shrimp, common shrimp, grass shrimp, black shrimp, California shrimp and black tailed shrimp. The species has been commercially fished from 1869 to the present. Role in the Bay food web This shrimp species is "an important part of the estuarine food web" in the greater San Francisco Bay. It feeds on bivalves, amphipods and foraminiferins, and is prey for various fish, including striped bass, white sturgeon, Pacific tomcod and shellfish such as Dungeness crab. Its diet is "heavily influenced by predator size, temperature-salinity preferences, and prey availability." Lifecycle The shrimp are short-lived, with a lifespan ranging up to 18 months for males and 30 months for females. The males spawn once, while longer-lived females spawn twice. Some evidence indicates the species may be protandrous hermaphrodites, which means that surviving males are transformed into females after one year of life. This may account