Qualitative and quantitative study of copepods in damietta harbor, egypt
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The qualitative and quantitative dynamics of the copepod community in Damietta Harbor was studied through zooplankton samples collected monthly from May 2003 to April 2004. The copepods community was represented by 21 species, belonging to calanoids (9 species), cyclopoids (5 species) and harpacticoids (7 species). A few species appeared to be persistent, while the majority of copepods were recorded either intermittently or rarely. The abundance of copepods showed wide range of variations (7x103 - 175 x103 organisms/ m3), and the annual cycle of the standing stock displayed bimodal peaks in June and August-September. The nauplii and copepodides constituted the bulk of copepods count (71.6% and 12.3% respectively). Of the adult forms, Oithona nana was the most abundant species, forming 8.1% of the total copepods, followed by Euterpina acutifrons (3.8%) and Paracalanus parvus (2.5%). Most of copepod species displayed distinct seasonal occurrence relative to environmental conditions. The stepwise regression analysis based on the annual average revealed that temperature was the most important factor controlling the size of standing stock of copepods in Damietta Harbor, while on seasonal bases, Chlorophyll a, pH and salinity seem to play a role in the copepods abundance. The cluster analysis demonstrated different types of association between copepods species, while Shannon-Weaver Diversity Index reflects relatively pronounced changes in biodiversity of the copepods community.