Prevalence of Marine Zooplankton around Port Sudan

Abstract

Marine zooplankton and some physical parameters (water temperature and transparency) and chemical parameters (salinity, pH and phosphate, nitrate, nitrite and oxygen) were studied from November 2009 to October 2010, at six stations around Port Sudan. The stations were: Tires Factory (station 1), Fish market (Station 2), Open Sea (Station 3), the harbour entrance (Station 4), the Faculty of Marine Sciences and Fisheries (Station 5) and Sea Land (Station 6). Marine zooplankton was sampled, preserved, stained and identified according to the standard methods. The physical and chemical parameters were determined following standard methods. Fifteen groups of zooplankton (calanoida copepods, cyclopoida copepods, branchyuran zoea, fish eggs, cladocerans, oikopleura, shrimp larvae, sagitta, cumaceans, tintinids, gastropod larvae, radiolarians, napulii, medusae, and polychaete larvae) were recorded from the different stations at different frequencies. The highest number of zooplankton was recorded in May (13430 ind. /m3). Calanoida copepods, cyclopoida copepods were the dominant groups and cladocerans were the least recorded. The highest number recorded in a station was (18998 ind/m3) in station 1 and the least was (5519 ind/m3) at station 6. Multiple correlation analysis was used to quantify the relationship between the total number of zooplankton and the physical and chemical parameters at each station. The correlation was significantly high (p<0.05) in station 4 and low in station 5. A positive relationship was found between dissolved oxygen concentration, transparency and nitrate concentration with the total number of zooplankton. A significant correlation (p<0.05) was found between high salinity and low total number of zooplankton. The study derived a mathematical model correlating total zooplankton with the physical and chemical parameters studied. This model perhaps may be the first of its kind in the Red Sea. The study recommends deriving similar models from other parts of the Sudanese coast and the region, and verifies the feasibility of its application with focus on the physical and chemical parameters with highest impact on marine zooplankton. This will reduce the effort and resources expended in these studies.