population dynamics, rational fishing, intensity and selectivity of fishing, emissions, regulation of the level of fishing impact, stock-market-fishing system

The article proposed to discuss a concept of new strategy for the sustainable use of populations of aquatic organisms using as an example a fishery for Walleye Pollock in the Far Eastern seas of the Russian Federation. It is shown that the current regulations governing the impact of fishing contained in the Fishing Regulations do not quite consider changes related to the dynamics of pollock populations parameters. As a result, there is an uncontrolled and often negative impact of fishing, which leads to changes in the phenotypic and size-age structure of W. Pollock populations being fished, which ultimately affects the profitability of fishing. It is proposed to develop a separate strategy for each W. Pollock stock unit, which annually regulates the level of fishing impact, depending on the state of the stocks and market conditions. The proposed strategy concept makes it possible to regulate not only the allowable volume of catch, but also the size structure of catches, by changing the fishing parameters every year. It will keep the harvested stocks stable and will help to obtain the maximum possible fishing profitability.

Long-term fishing impact on the Senegalese coastal demersal resources: diagnosing from stock assessment models

For the first time in Senegal, assessments based on both stochastic and deterministic production models were used to draw a global diagnosis of the fishing impact on coastal demersal stocks. Based one national fisheries databases and scientific trawl surveys data: (i) trends in landings since 1971 were examined, (ii) abundance indices of 10 stocks were estimated using linear models fitted to surveys data and commercial catch per unit efforts, and (iii) stock assessments were carried out using pseudo-equilibrium Fox and Pella-Tomlinson models and a Biomass dynamic production model fitted in a Bayesian framework to abundance indices. Most stocks have seen their abundance sharply declining over time. All stocks combined, results of stock assessments suggest a 63% reduction compared to virgin state. Three fifth of demersal stocks are overexploited and excess in fishing effort was estimated until 75% for the worst case. We conclude by suggesting that the fishing of such species must be regulated and an ecosystem approach to fisheries management should be implemented in order to monitor the whole ecosystem.

PROSES PENANGKAPAN DAN TINGKAH LAKU IKAN BAGAN PETEPETE MENGGUNAKAN LAMPU LED

Konsep aktivitas penelitian dan pengembangan teknologi penangkapan ikan pada masa yang akan datang tidak hanya ditujukan meningkatkan hasil tangkapan tetapi juga ditujukan untuk memperbaiki proses penangkapan (capture process), mengurangi fishing impact terhadap lingkungan dan bio-diversity. Penelitian dilakukan dengan tujuan untuk menganalisis tahapan pengoperasian dan permasalahan dalam mengoperasikan liftnet (bagan petepete) khas masyarakat Sulawesi Selatan khususnya Kabupaten Barru dan masukan terhadap taktik dan metode penangkapan ikan, melalui: analisis tahap proses pengoperasian dan analisis tingkah laku ikan di sekitar pencahayaan pada bagan petepete (boat lift net) yang menggunakan lampu LED. Penelitian ini dilaksanakan di perairan Kabupaten Barru-Selat Makassar, Sulawesi Selatan. Pengamatan lapang dilakukan dari bulan Juni sampai Agustus 2014 (20 trip). Analisis deskriptif dilakukan untuk melihat tahapan operasi penangkapan, sedangkan pengamatan tingkah laku ikan diamati dengan menggunakan fish finder. Tahapan pengoperasian bagan petepete adalah: persiapan operasi, menuju fishing ground, proses penyalaan lampu, proses penurunan waring (setting), proses menunggu kawanan ikan (soaking), proses pemadaman lampu, proses pengangkatan waring (hauling), pengambilan hasil tangkapan, dan proses pengangkatan waring ke atas bagan. Analisis tingkah laku ikan memperlihatkan pola pergerakan kawanan ikan mendatangi pencahayaan berada pada kedalaman 5-10 m dan 20-40 m dari segala arah pada saat semua lampu dinyalakan. Pola Kawanan ikan terkonsentrasi di sekitar catchable area pada saat hanya satu lampu yang dinyalakan disetiap sisi dengan jumlah kawanan semakin sedikit tetapi kepadatan kawanan yang besar disebabkan bergabungnya beberapa kawanan ikan sehingga kawanan ikan semakin membesar.