SEASONAL VARIATION OF PHYTOPLANKTON IN ECONOMICAL IMPORTANT LAKE AND ENVIRONMENTAL INTERACTION ON FISH PRODUCTION (LAKE BARDAWIL)

SEASONAL VARIATION OF PHYTOPLANKTON IN ECONOMICAL IMPORTANT LAKE AND ENVIRONMENTAL INTERACTION ON FISH PRODUCTION (LAKE BARDAWIL)

Rawheya Abd-Elatif
¹ and Tartiel El-Sayed Badawy ²

¹Botany Department, Faculty of Science, Al Azhar University, Cairo.

²Central Laboratory for Aquaculture Research, Ecology and Biology Department, Agricultural Research Center, Cairo, Egypt.

Abstract

Lake Bardawil situated on the Egyptian coast of the Mediterranean Sea, Northern of Sinai-Egypt. Lake Bardawil has a unique ecosystem and it is an oligotrophic, shallow and its surface area is about 650 Km2. The lake is used as an important source of fish. In the last few years the fish production decreased to a lower rate. The productivity of phytoplankton is affected by environmental factors of the lake. For these reasons a study was carried out on the environmental variables which control the growth of phytoplankton and interaction on fish production in the lake. The study reveals that the nutrient concentration especially P and N were very low and cannot support the growth of phytoplankton, to improve the fish production in the lake it is important to increase the nutrient source. Lake is under pollution threatening as connected to El-Salam Channel, which must be taken into consideration for protection of the lake ecosystem as one of Egyptian treasures. The dominant groups were Diatom which was found in all stations and seasons, while Green, Blue green and Euglenophyta were represented only by few species. The results also demonstrated the efficiency of phytoplankton in reducing the pollutant effect of some heavy metals in water (P< 0.05), the higher values of heavy metals (Fe, Zn, Cu, Mn and Cd) were accumulated in fish during autumn season, while the lowest value was obtained at fish (Seabass and Seabream) during winter season (P< 0.05) and decreasing their negative impact as well as pH, dissolved oxygen and unionized ammonia. Body dry matter (%) was not significantly(P< 0.05), while CP%, EE% and ash% significantly(P< 0.05) differed among produced lower value of Glucose and Uric acid, affected by density of phytoplankton while gave higher value of AST, ALT in plasma. Phtoplankton are the natural feeds of many aquaculture species, and are the basis of the natural food, where it gave better water quality and fish safety adverse health human effects. Fish production of the
Lake Bardawil can be improved perhaps by phytoplankton aquaculture with respect to its area.

Key words: Lake Bardawil, Seabass,
Seabream, fish production, environmental, Phytoplankton, heavy metals, pollution.