Composition, density and spatial distribution of zooplankton on wet season (June-August) in Inner Ambon Bay

Abstract

Inner Ambon Bay is part of Ambon Bay, it is semi closed area and is a small pelagic fish fishing ground, especially anchovy. The anchovy is zooplankton predator therefore existence of anchovy is affected by abundance of zooplankton. The aim of the research are to know composition, density and spatial distribution of the zooplankton during wet season (June to August). Data of zooplankton composition were obtained from sampling by using plankton net at 10 observation stations, meanwhile, data of densities were collected using scientific hydroacoustic system, BioSonic DTX, on six parallel transect lines and one cross-parallel transect line. Geostatistical analyses technique was used to describe horizontal distributions of zooplankton and vertical distributions were plot in the graphs. The result shows that zooplankton community dominated by Copepod and meroplankton. Highest density was found on August (9393/m2 ), while lowest density was on June (903 ind./m2 ). Vertical distribution of zooplankton shows that highest density was found near surface and decrease to deeper water coloumn. On the horizontal distribution, lower densities (0 – 400 ind./m2 ) occupy wider space, they evenly distributed in western, middle (north to south) and east, on the contrary, higher densities (3000- 5000 ind./m2 ) occupy smaller space i.e in the south-west, south and east to north-east of Inner Ambon Bay