Intraksi trofil komunitas ikan sebagai dasar pengelolaan sumberdaya kan di perairan Teluk Kendari Sulawesi Tenggara

Abstract

The objectives of this research is to analyze trophic interaction among fish population and to arrange alternative management of fish resources in Kendari Bay waters. This research was conducted in Kendari Bay, Southeast Sulawesi from August 2009 to July 2010 at three different sampling sites. The fish was collected using experimental gillnets (with different mesh sizes of ¾, 1, 1¼, 1½, 2, 3, and 4 inches) and push net (diameter 1 meter and mesh size of 0.04 inch). Abundant and biomass of food resources were determined by APHA methods. Food analysis was determined by using index of preponderance, trophic niche breadth and trophic niche overlap. During the research, 76 species, 54 genera belong to 40 families of fish were caught and found Clupeidae family in lower trophic level was dominant. The juvenile fish (73 species) that occupied the waters of Kendari Bay were more than the adult one (49 species). The lowness of the length and body weight on the fish in this waters indicated that the Kendari Bay used by most of fish populations as nursery ground. Food habits of the dominant fishes (15 species) consisted of phytoplanktivore herbivores and carnivores, with a large niche breadth on fringescale sardinella (Sardinella fimbriata) and indian oil sardine (S. longiceps). The similarity in utilization of food resources occurred among the 14 dominant fish populations so that opportunity of competition is high due to the low availability of food resources (phytoplankton) (0.41–2.87 mg chl a m-3). According to the data, the management of fish resources through of trophic interactions approach can be done by several ways, which are the habitat protection efforts, control of turbidity in the waters, and development of recreational fisheries of the Kendari Bay. The development of recreational fisheries in the waters of Kendari Bay should be supported by establishment of protected area for nursery and spawning of the fish populations. Also, it needs the favorable environment condition for the fish through turbidity control in Kendari Bay.

Penelitian interaksi trofik komunitas ikan di perairan Teluk Kendari Sulawesi Tenggara bertujuan untuk menganalisis interaksi trofik antar populasi ikan dan untuk menyusun alternatif pengelolaan sumber daya ikan di perairan Teluk Kendari. Penelitian dilaksanakan di perairan Teluk Kendari dari bulan Agustus 2009 sampai Juli 2010 pada tiga zona penelitian yang berbeda. Contoh ikan ditangkap dengan jaring insang percobaan dengan panjang 30 meter untuk setiap ukuran mata jaring ¾, 1, 1¼, 1½, 2, 3, 4 inci dan seser dengan garis tengah 1 meter dan mata jaring 0,04 inci. Parameter lingkungan, kelimpahan, dan biomassa sumber daya makanan alami ditentukan berdasarkan metode APHA. Analisis makanan alami setiap populasi ikan ditentukan berdasarkan indeks bagian terbesar. Luas relung makanan dan tumpang tindih relung makanan ditentukan berdasarkan formula Colwell & Futuyama dan Schoener. Tingkat trofik ditentukan berdasarkan formula Christensen & Pauly dan selanjutnya dibuat jejaring makanan untuk menggambarkan pergerakan aliran energi yang terjadi dalam komunitas ikan di perairan Teluk Kendari.