Study on the Aggregation Mechanism of Small Pelagic Fish around Rumpon and Its Fisheries of Development in Pasauran Waters, Province of Banten

Abstract

Rumpon (Fish Aggregating Device) is an auxiliary gear operated to attract and aggregate fish. The use of rumpon for fishing activities has improved the effectivity and efficience of several fishing gear. However, the fast growing of rumpon utilization has raised a great concern on the sustainability of the fish resources. The rumpon management for responsible fisheries should consider the aspects of biology, location, environment, fishing gear, social and economic. The aggregation mechanism of pelagic fish around rumpon has not fully understood and its usage in a responsible manner further elaboration also needed. For this purpose, analysis were conducted on the anatomy and morphology of 3 kinds of rumpon's attractor materials, i.e Cocos nucifera, NypaJLuctican and Areca catechu leaves. The genus composition of plankton and periphyton were identified, obse~-vationosn fish behavior, stomach content, Gonado Somato Index were carried out. Experimental fishing was conducted by using payang bugis. The result show that the Cocos nucifera leaves are the best attractor material based on the thickness of cuticle, thickness of epidermis, density of periphyton, and number of fish species in all seasons. Further, the Gonado Somato Index (GSI) of small pelagic fish were caught around rumpon are GSI I 4%, GSI I1 33% and GSI I11 35%. This result indicated that the small pelagic fish caught around rumpon are 'immature fish' and could cause recruitment overfishing. The periphyton in the attractors were also found in the stomach content of 6 small pelagic species fish around rumpon. The aggregation mechanism aggregation of pelagic fish around rumpon, therefore, more likely caused by food chain process, beginning with colonization of microorganism on leaves attractor, aggregation of micro organism prey around rumpon, aggregation of filtering and predator fish. Next, application of Hilborn and Medley Model on the rumpon fisheries in Pasauran waters revealed that the optimum number of rumpon is 4 units, for the water area of 11 5.4 km2, and the mean distance of each rumpon is 5 km (about 3 nautical miles). The 4 units rumpon in Pasauran waters could render 154.4 ton of total catch/year with a profit of 38.2 million rupiahlyear. The rumpon fisheries in Pasauran have not met with the criteria of the Code of Conduct for Responsible Fisheries. The GSI of small pelagic fish were caught around rumpon indicated that the rumpon could cause recruitment overfishing. Rationalization of the existing 45 to 4 units rumpon in Pasauran waters is recommended to ensure the sustainability of the fisheries.