Seasonal Distribution and Abundance of Crustacean Zooplankton in Lake Erie, 1970

Abstract

The lakewide horizontal distribution and seasonal abundance of the cyclopoids, cladocerans, and calanoids in Lake Erie from April to December 1970, are presented.Over much of the year cyclopoids dominated by Diacyclops bicuspidatus thomasi were most numerous with offshore centers of abundance. Several species of cladocerans, often with short peaks of occurrence, were most abundant during summer in the Western basin and associated with south shore population centers in the Central basin. Calanoids were frequently much less abundant than either of the two groups but present in the same areas as the cladocerans.Most species present were short-lived with a high reproductive potential. Environmental clues are postulated to control specific abundance making group numbers more constant. Several life-cycle patterns were evident including species with spring–fall maxima and those with a single peak.Timing of peak abundance of certain species and groups varies from west to east in the same fashion as temperature differences giving rise to east–west gradients of abundance which change with season. Cladoceran and calanoid groups show similarities in distribution pattern with estimates of particulate organic material rather than with algal abundance resulting in north–south gradients of abundance.