COMPARATIVE STUDIES ON ZOOPLANKTON COMMUNITIES ALONG THE EASTERN AND WESTERN COASTS OF THE GULF OF SUEZ, EGYPT

Abstract

The zooplankton communities of the Gulf of Suez were studied during the period from autumn 2011 to summer 2012. The results showed that, a total of 51 species of holoplankton belonging to 36 genera, distributed among 5 phyla, in addition to 6 groups of meroplankton were collected from the Gulf of Suez. The eastern side was inhabited by 49 species of holoplankton compared to 51 species along the western one. All groups of meroplankton were recorded from both sides. Copepods dominated all other holoplankton species (33 species forming 64.7% of total species number), most of them were cosmopolitan and few species were restricted to at least two neighboring areas. The plankton density averaged 27870 and 21028 organisms/m³ for the eastern and western sides, respectively, with remarkable seasonal variations in species number and density. The highest number of recorded species was 47 and 48, recorded in both eastern and western sides, respectively during spring, associated with a maximum density (40164 and 31586 organisms/m³) during the same season; while the lowest number of species (19 and 23) was recorded during winter at both sides with low density estimated as 9218 and 6493 organisms/m3, for the eastern and western sides, respectively. The present data also showed sharp fluctuations in distribution, characterized by disappearance of several species during winter. Although calanoids dominated all other orders of Copepoda in species number (22 species), but cyclopoids (two species) were plentiful in number of individuals (density). The values of similarities between sites were high, reaching above 0.80 at both sides, and were relatively higher at the northern stations than mid- and southern stations at the eastern side, but the reverse was noted, showing high values of similarity at the southern stations of the western side.