Abundance and biomass of Cladocera (Crustacea) in Vaya Lake

Abstract

The number and biomass of Cladocera in Vaya Lake during the period 2003 - 2007 was studied under the conditions of increased anthropogenic pressure. The total number of cladocerans by station and by species, as well as their biomass, was determined. A dendrogram of similarity in species and quantitative composition of Cladocera was made. St. 1 and St. 5 are distinguished by the equal and lowest abundance of D. magna, and the very similar and highest abundance of M. micrura. Stations 3, 4, 11, and 12 had the highest Cladocera abundances, which were mainly due to close D. longispina and M. micrura. St. 9, 8, 2 and 7 form one group with more than 83% similarity. They show similar abundances of D. pulex. The dendrogram of similarity in species composition and biomass for the cladocerans showed 75% similarity among all stations except st. 5, which clearly stands out with the lowest total biomass.

Keywords

• zooplankton
• anthropogenic pressure
• eutrophication