Note
During 1973-74 biweekly collections of zooplankton in Jobos Bay, Puerto Rico revealed that major differences in the abundance and variety of several populations were related to water circulation, seasonal rainfall, and diel behavior. Abundance levels increased about twofold from coastal to isolated regions of the bay but at least twice as many species occurred in the coastal areas. Rapid, short-term changes in abundance, pulses of about one order of magnitude, occurred shortly before and during the wet season. Diel differences in density, most notable among the copepod, Acartia tonsa, coincided with a seasonal increase in abundance.