Distribución vertical de zooplancton en El Embalse Arenal, Costa Rica

Abstract

The vertical distribution of Bomina, Daphnia, Ceriodaphnia, Diaptomus and cyclopoids was studied for a 48 hours period in Arenal Reservoir, Costa Rica. In general the zooplankton decreased during day time across the water column. Daphnia, Diaptomus and the cyclopoids had a constant depth distribution with time, whereas Bosmina, and Ceriodaphnia showed slight evidence of vertical migration. Due to the scarcity of planktivorous fishes in the limnetic zone of the reservoir, the migration of small-sized cladocerans is purpoudtely explained by invertebrate predation pressure (e.g. cyclopoids).