Speciation and succession of zooplankton in Esquimalt Lagoon, BC

Abstract

The speciation, abundance and seasonal succession of the zooplankton in Esquimalt Lagoon was studied during 1978 and part of 1979. A brief comparison with the zooplankton in adjacent waters was also made. The lagoon is characterized by a low species diversity and a population which is dominated in the spring and early summer by the copepod Acartia clausii and to a lesser extent barnacle cauplii and the cladoceran Podon. Only very low numbers of other species are found at other times of the year. The increase in zooplankton population in the spring coincides with the spring phytoplankton increase together with a warming trend. The decline of the population in July appears to be associated with fish predation, a reduction in fecundity due to temperature and adverse conditions in the sediment which inhibit egg hatching.