The Biomass and Species Composition of Zooplankton Populations in Gorgon Bay

In order to estimate the species composition and biomass of the zooplankton in Gorgan Bay, more than 150 samples were collected from the surface and near the bottom (max. 5m) using 55 micrometer mesh sized net. Over 30 zooplankton species belonging to five phyllums were identified, among which the biomass and the species composition of Copepoda were estimated. Copepods constituted nearlly 70% of the zooplankton populations during the spring, followed by the Rotifers, which comprised almost 13.5% of the total biomass. Diversity and abundance of copepods and cladocera were more than the ether groups, and among the Copepods Acartia clausi had the highest biomass and abundance in each month and at all the stations. The seasonal changes and the life cycle of the zooplanktons in Gorgan Bay were in such a way that one or two peaks in the biomass occur during spring, summer and winter. In some months when we moved toward the littoral regions of the bay, due to the changes of the tempreture, th.....