Purwanto

PERKEMBANGAN DAN OPTIMISASI PRODUKSI PERIKANAN LAUT DI INDONESIA

Tulisan ini menjelaskan perkembangan kegiatan penangkapan dan produksi perikanan laut Indonesia pada kurun waktu 22 tahun terakhir. Jumlah dan daya tangkap armada perikanan laut telah berkembang pesat dan menghasilkan peningkatan produksi perikanan. Perkembangan produksi tersebut cenderung melambat pada 10 tahun terakhir dan mendekati level-off, namun volume produksi ikan tersebut tidak mencapai tingkat optimalnya. Beberapa permasalahan yang menyebabkan capaian sub-optimal tersebut antara lain adalah terjadinya overcapacity pada armada perikanan yang berdampak terjadinya overfishing, struktur armada perikanan yang didominasi perahu dan kapal berskala kecil yang beroperasi tidak jauh dari pantai menggunakan alat tangkap dengan selektivitas rendah, dan adanya praktek penangkapan ikan secara ilegal. Permasalahan lainnya adalah karakteristik sumberdaya ikan yang terdiri dari banyak species yang bermigrasi ke dan/atau dimanfaatkan bersama oleh nelayan dari daerah atau negara yang berbeda. Pengendalian upaya penangkapan ikan dalam kerangka pengelolaan perikanan dengan mempertimbangkan hal-hal tersebut perlu dilakukan untuk optimisasi produksi lestari. Pilihan pengendalian untuk masing-masing wilayah pengelolaan perikanan dijelaskan pada tulisan ini. This paper describes the development of fishing activities and marine fisheries production of Indonesia during the last 22 year period. The number and fishing power of fishing fleet increased considerably, resulting in higher quantity of marine fisheries production. The growth of the production tends to be slower in the last decade approaching a level-off. However, the quantity of production was much lower than the optimal level. Some problems causing this suboptimal achievement included overcapacity of fishing fleet resulting in overfishing, domination of the fishing fleet by small-scale boats operating less selective fishing gears in the waters close to coastal areas, and illegal fishing practices. Another problem was multispecies nature of fisheries, with some fishery resources migrated to and/or were shared amongst fishers from different districs, provinces or countries. Control of fishing effort in the fisheries management famework taking into account these matters should be conducted in order to optimise sustainable production. Alternative control measures for each fisheries management area are explained here.

THE BIOLOGICAL OPTIMAL LEVEL OF THE ARAFURA SHRIMP FISHERY

This paper briefly describes the past development of the shrimp fishery in the Arafura Sea, including intensity of illegal fishing, and presents the impact of increasing fishing pressure on the quantity of catch and biomass. The maximum sustainable yield and the optimum fishing effort are estimated.

ANGKA ACUAN SASARAN UNTUK PENGELOLAAN PERIKANAN LEMURU DI SELAT BALI DENGAN TUJUAN BERAGAM

Kriteria pengelolaan perikanan dalam kerangka pembangunan nasional, yaitu pro-growth, pro-poor, pro-job dan pro-environment, mengarahkan pengelolaan perikanan lemuru di Selat Bali untuk mengoptimumkan produksi lestari dan keuntungan perikanan, serta meningkatkan keuntungan per satuan kapal dan peluang kerja sebagai nelayan. Masing-masing tujuan tersebut perlu ditetapkan angka acuan sasarannya yang diharapkan dicapai dalam pengelolaan perikanan. Mengingat tujuan tersebut saling bertentangan, sehingga tidak dapat dicapai bersamaan, perlu ditentukan tingkat kompromi optimal diantara tujuan tersebut dan angka acuan sasarannya. Tulisan ini menyajikan model pemrograman matematika untuk optimisasi dengan empat tujuan pengelolaan, serta menggunakannya untuk mengestimasi angka acuan sasaran dan jumlah optimal kapal penangkapnya. Hasil optimisasi dengan pemberian bobot prioritas yang sama terhadap empat tujuan pengelolaan perikanan dalam kerangka pembangunan nasional menunjukkan bahwa angka acuan sasaran pada tingkat kompromi optimal dicapai dengan pengendalian upaya penangkapan pada tingkat yang setara dengan daya tangkap 146 kapal pukat cincin. Angka acuan sasaran yang sama dihasilkan dari optimisasi dengan pemberian bobot prioritas yang lebih tinggi terhadap dua tujuan pengelolaan perikanan sesuai dengan Pasal 6 Undang Undang Perikanan tahun 2004. The criteria of fisheries management undertaken in a framework of national development, particularly pro-growth, pro-poor, pro-job and pro-environment, guide the management of lemuru fishery in the Bali Strait to optimising lemuru production and fishery profit, and increasing per vessel profit and job opportunity as fishers. As those objectives were conflicting that couldnot be achieved simultaneously, it is necessary to seek an optimal compromise amongst several conflicting objectives and to estimate their target reference points. This paper presents a mathematical programming model accommodating four objectives of fisheries management, and the utilisation of this for estimating the target reference points and the optimal number of fishing vessels. The result of optimisation shows that target reference points at the optimal compromise levels for the four conflicting objectives, with equal priority, of fisheries management supporting the national development could be achieved by controlling fishing effort at the level equal to 146 purse-seiners. The same target reference points resulted fromthe analysis providing higher priority to the objectives of fisheries management stated in Article 6 of Fisheries Act of 2004.

PERFORMANCE OF A FISHERY HARVESTING DIFFERENT MINIMUM SHRIMP SIZES IN THE ARAFURA SEA

Avoiding overfishing and ensuring the sustainability of the shrimp stock in the Arafura Sea are of prime importance for fishery management. Exploited shrimp stock consists of several cohorts, and grows considerably with age. When the shrimps are caught before the cohort has had the opportunity to achieve its optimum biomass level, the fishery will lose much of the potential benefit that could be achieved by catching them in the near future. Therefore, a bio-economic approach was developed, on the basis of the length-based Thompson & Bell model, to evaluate the impact of harvesting different size of shrimps on fishery performance. The result of analysis shows that the fishery achieved the optimal total profit when the shrimp size at first-capture and fishing mortality were 29 mm CL and 0.50, respectively. The total profit to the fishery would be sub-optimal when the shrimp size at-first-capture was smaller or larger than the optimal size. Further, it was more economical to harvest shrimps at the larger size and higher fishing mortality, and resulting in higher total profit, when natural mortality decreased.