Effect of Seasonal Monsoons on Calanoid Copepod in Chabahar Bay-Gulf of Oman

Seasonal abundance and diversity of calanoid copepod was studied from zooplankton samples collected between August 2007 and May 2008 in Chabahar Bay (one of the Iranian coasts of Gulf of Oman located on the southeastern Iran (25° 17 45N- 60° 37 45 E). This area is influenced by seasonal monsoons. Five stations were investigated along the Bay. Zooplankton was collected with vertical plankton tows using 100-μm mesh net. The net was towed obliquely from a depth near the bottom to the surface. The main peak of calanoid density was recorded in SW-monsoon with an average of (445.19±126.16 individual. m-³) and formed 62.40% of the total copepod while pre-monsoon was characterized by the lowest calanoid density (153.75±54.20 ind.m-³) and formed 26.73% of the total copepod. The results suggested calanoid abundance regulated by variations in chlorophyll (a) concentrations and temperature. Overall, 45 calanoid species representing 11 families and 15 genera were identified during four surveys. SW-monsoon was characterized by highest diversity index (H =1.95) and species richness (D= 1.66). Pre-monsoon showed lowest numerous of calanoid species (mean 13), diversity index (H =1.42), and species richness (D=1.39)