Nur Laila Rahayu. B2A015023. Feeding Ground Quality of Estuary Serayu, District of Cilacap (Supervisor: W. Lestari and Erwin Riyanto Ardli).
The land use changes of Serayu River resulted on high sedimentation and accumulation of materials in downstream. This phenomenum will lead to decreasing of primary and secondary productivities. Both would reflecting to the quality of the feeding ground. The purposes of this research were to describe the feeding ground quality of Estuary Serayu based on primary and secondary productivities, to determine the environmental factors driven the species richness of plankton, and to evaluate the correlation between primary and secondary productivities. Survey with purposive sampling technique was applied in this research. Estuary Serayu was divided into five sites based on salinities. The nearest site to the sea (1) with 26 ‰ and the furthest site (5) with 8 ‰. Sampling was conducted at high and low tide times on August until November 2016. The data of species richness and abundance plankton were analyzed descriptively and the correlation between environmental factors and plankton were calculated by PCA. The feeding ground quality was categorized based on abundance and percentage of species richness of plankton as natural feeds of fish. The result shown that the abundance of phytoplankton was 4.106-18.875 ind.L-1, the primary productivity was 3,31-5,21 mg.C.m-2.d-1 and the abundance of zooplankton was 259-1036 ind.L-1 these indicated that estuary of Serayu possessed poor productivity. The primary and secondary productivities were positively correlated to penetration of solar (r=0,8), TSS (r=-0,9) and pH (r=0,8). The secondary productivity was determined 12% by primary productivity and 88% by unidentified factors. The feeding ground qualities estuary of Serayu were categorized less promote to the fishery, since it had poor productivity.
Keywords: Feeding ground, primary productivity, secondary productivity, estuary of Serayu River.