Temporal and spatial variations in salt pond environments and implications for fish and invertebrates

I studied water quality and the distribution of aquatic species in a series of brackish and hypersaline (20-85 ppt) salt evaporation ponds in south San Francisco Bay between May 1985 and November 1986. Physical and chemical characteristics in the ponds were distinct from, and often more stressful than, the surrounding Bay. Invertebrate abundance varied substantially among ponds and seasons. Brine shrimp (Artemia salina) and copepods were the dominant invertebrates in high salinity ponds, whereas benthic and epibenthic invertebrates were most abundant in low salinity ponds. Slight changes in salinity in the range of 30-40 ppt produced large changes in community composition.;Fifteen fish species were collected in the ponds. Six species were able to reproduce in some ponds, and topsmelt (Atherinops affinis) and longjawed mudsucker (Gillichthys mirabilis) were able to reproduce to 75 ppt salinity. The remaining nine species occurred as transients from the Bay.