VARIASI KOMUNITAS PLANKTON DAN PARAMETER OSEANOGRAFI DI DAERAH PENANGKAPAN IKAN PELAGIS DI PERAIRAN MALANG SELATAN, JAWA TIMUR

Abstract

The existence of plankton plays an important role in the abundance of fishery resources in a fishing area. The lack of information related to the abundance of plankton in the fishing grounds encouraged this study.This study aims to determine the variation of the plankton community and its relationship to oceanographic parameters, as well as the spatial distribution of plankton in the fishing ground of South Malang water. The purposive sampling method with zigzag technique at 10 sampling sites was used in data collection. Sedwicgk rafter counting cells were used in plankton counting methods. The plankton samples were taken horizontally and vertically at 1 and 15 m depth by 20 μm meshsize planktonnet, while in situ oceanographic parameters were collected by aqua quality sensor AAQ-1183C. The results showed that phytoplankton abundance was 49.764 cells/m3, dominated by Chaetoceros (Bacillariophyceae), and zooplankton abundance of 894 ind/m3, dominated by Nauplius (Copepoda). The diversity and similarity index of phytoplankton and zooplankton are categorized as medium as 1.77-1.85 and 1.70-1.77; 0.58-0.59 and 0.77-0.79, respectively, while the dominance index was categorized as low as 0.27-0.28 and 0.24-0,27, respectively. Principal Component Analysis (PCA) analysis showed that the most important major oceanographic parameters for plankton community variation were turbidity, chlorophyll-a, dissolved oxygen and phosphate. T-test results show that the spatial distribution of phytoplankton abundance and zooplankton at depth of 1 m and 15 m are significantly different. This study provides important information on the plankton abundance and oceanography factors affected at fishing ground of South Malang water. Keywords: fishing ground, oceanography parameters, plankton community, South Malang Water