PERIKANAN PURSE SEINE DI LAUT JAWA YANG BERPANGKALAN DI PPN PEKALONGAN, STUDI KASUS : TONGKOL ABU-ABU (Thunnus tonggol)

Purse seine adalah alat tangkap yang banyak dioperasikan di Laut Jawa (WPPNRI 712). Alat tangkap ini banyak berkontribusi mendaratkan ikan pelagis di PPN Pekalongan. Penelitian ini bertujuan untuk mengkaji aspek perikanan tangkap dari purse seine di Laut Jawa yang berpangkalan di PPN Pekalongan. Penelitian ini dilakukan pada 2 Maret - 15 Mei 2020. Metode yang digunakan yaitu metode survey dan observasi langsung maupun di atas kapal penangkapan (purse seiner). Hasil penelitian ini menunjukkan komposisi hasil tangkapan selama bulan Maret - April terdiri dari ikan kembung (Rastrelliger spp), ikan layang (Decapterus spp), Ikan selar (Caranx sp), ikan tembang (Sardinella fimbriata), dan ikan pelagis kecil lainnya dengan ikan tongkol abu-abu (Thunnus tonggol) sebagai hasil tangkapan utamanya. Pengoporasian purse seine berlangsung pada pukul 06:00 – 18:00 WIB dengan lama setting-hauling 2-4 jam.

Benefits and Risks of the Technological Creep of LED Light Technologies Applied to the Purse Seine Fishery

This study is a first attempt to investigate the catch efficiency of LED light technology compared to the traditional incandescent lamp that is used in the purse seine fishery (PS) in the Central Adriatic Sea (Mediterranean Sea). Catches per unit effort were adopted to assess the performance of lighting systems, considering the electrical energy and the fuel consumption as effort units. Concerning the catch efficiency, the white LED, which emits the same light spectra as the incandescent lamp, increased the yield by over 2 times per consumption unit of energy and fuel. The yield efficiency increased up to approximately 6 and 9 times when adopting the pulsing white or blue LED, respectively. These increases were due to the energy savings resulting from the flashing of the white LED or by the greater water penetration of the blue LED. No significant difference in target species sizes was detected between the use of LEDs and the incandescent lamp. The results obtained from estimates of the hourly fuel consumption and CO2 emissions stress potential benefits in the reduction of the carbon footprint due to the use of LEDs within the PS fishery. Positive economic impacts were derived from the LED technology on the PS fishery, with the fuel cost-saving percentages all being higher than 60%. The LED technology clearly shows potential benefits at the economic level for the fishermen, and the possibility of mitigating indirect negative effects on the environment due to fuel combustion and greenhouse gas emissions. On the other hand, the application of new technology that improves the catch efficiency of fishing gears should be carefully considered. The lack of regulations controlling technological advancement could cause unwanted long-term effects.

Long-Term Patterns of Noise From Underwater Explosions and Their Relation to Fisheries in Southern California

Acoustic deterrents can reduce marine mammal interactions with fisheries and aquacultures, but they contribute to an increasing level of underwater noise. In Southern California, commercially produced explosive deterrents, commonly known as “seal bombs,” are used to protect fishing gear and catch from pinniped predation, which can cause extensive economic losses for the fishing community. Passive acoustic monitoring data collected between 2005 and 2016 at multiple sites within the Southern California Bight and near Monterey Bay revealed high numbers of these small-charge underwater explosions, long-term, spatio-temporal patterns in their occurrence, and their relation to different commercial purse-seine fishing sectors. The vast majority of explosions occurred at nighttime and at many nearshore sites high explosion counts were detected, up to 2,800/day. Received sound exposure levels of up to 189 dB re 1 μPa2-s indicate the potential for negative effects on marine life, especially in combination with the persistence of recurring explosions during periods of peak occurrence. Due to the highly significant correlation and similar spatio-temporal patterns of market squid landings and explosion occurrence at many sites, we conclude that the majority of the recorded explosions come from seal bombs being used by the California market squid purse-seine fishery. Additionally, seal bomb use declined over the years of the study, potentially due to a combination of reduced availability of market squid driven by warm water events in California and regulation enforcement. This study is the first to provide results on the distribution and origin of underwater explosions off Southern California, but there is a substantial need for further research on seal bomb use in more recent years and their effects on marine life, as well as for establishing environmental regulations on their use as a deterrent.

Conditions for stability of the “vessel-purse seine” system during purse seining

In the process of tightening the rings of the lower seine line, significant forces of hydrodynamic resistance of the netting can capsize the vessel or pull it into the encircled seine area. There is a risk of damage to the propeller-rudder system of the vessel. The list and trim of a fishing vessel can occur. It affects the safety and comfort of the crew, leads to malfunctions of fishing equipment and mechanisms, and can cause accidents. During the vessel’s operation, there are a number of measures to improve stability. However, when designing fishing equipment, it is necessary to know the forces acting from the seine side on the vessel. The article discusses the relationship between the vessel and the seine during purse seining. On the basis of the developed mathematical model of the tension force of the purse rope, taking into account the geometrical parameters of the warp during purse seining, conditions for stability of the “vessel-purse seine” system were obtained.

Application of Feature Point Matching Technology to Identify Images of Free-Swimming Tuna Schools in a Purse Seine Fishery

Tuna fish school detection provides information on the fishing decisions of purse seine fleets. Here, we present a recognition system that included fish shoal image acquisition, point extraction, point matching, and data storage. Points are a crucial characteristic for images of free-swimming tuna schools, and point algorithm analysis and point matching were studied for their applications in fish shoal recognition. The feature points were obtained by using one of the best point algorithms (scale invariant feature transform, speeded up robust features, oriented fast and rotated brief). The k-nearest neighbors (KNN) algorithm uses ‘feature similarity’ to predict the values of new points, which means that new data points will be assigned a value based on how closely they match the points that exist in the database. Finally, we tested the model, and the experimental results show that the proposed method can accurately and effectively recognize tuna free-swimming schools.

Faktor-Faktor Yang Mempengaruhi Hasil Tangkapan Armada Perikanan Skala Kecil di Kei Kecil Bagian Timur , Kepulauan kei

Dinamika armada perikanan skala kecil merupakan upaya penangkapan yang dilakukan nelayan kecil untuk memaksimalkan hasil tangkapan dalam setiap musim. Upaya penangkapan yang terus menerus tanpa kontrol dapat berdampak pada kompetisi armada penangkapan yang dapat menyebabkan penurunan sumberdaya ikan tertentu, karena itu perlu dilakukan identifikasi terhadap faktor-faktor yang mempengaruhi hasil tangkapan armada perikanan skala kecil. Penelitian ini bertujuan mengidentifikasi faktor-faktor yang mempengaruhi hasil tangkapan armada perikanan skala kecil. Metode penelitian menggunakan metode survei, penentuan responden dengan teknik purposive sampling. Analisis data yang digunakan adalah analisis deskriptif komparatif dan General Linear Model. Hasil penelitian menunjukan bahwa hasil tangkapan armada penangkapan bagan, purse seine, gillnet hanyut, gillnet dasar, pancing tonda dan pancing ulur dalam penelitian ini secara umum dipengaruhi secara nyata oleh variabel kapasitas armada. Jumlah dan kaspasitas armada perikanan skala kecil yang tidak di kontrol dan diatur dengan baik oleh pihak manajemen yakni Dinas Perikanan Provinsi Maluku telah berdampak kompetisi armada perikanan secara bebas dalam setiap musim di Kepulauan Kei. Kompetisi armada perikanan skala kecil dapat menyebabkan sumberdaya ikan yang semakin menurun dari waktu ke waktu, karena itu perlu dilakukan monitor dan pengaturan armada perikanan skala kecil dengan teknik input dan teknik kontrol.

Application of Surplus Production Model to the Yellowfin Tuna Thunnus albacares in the northern and western parts of Aceh waters

Yellowfin tuna Thunnus albacares is one of pelagic fish that has high potential and economic value in Banda Aceh. Utilization of this resource in Banda Aceh is using purse seine units, with the number of purse seines continuously increasing. Therefore, management needs to be done so that optimal productivity can be maintained. This study discusses the estimation of catch and effort at maximum sustainable yield (MSY) of yellowfin tuna based on catch per unit effort (CPUE) and purse seine production in Banda Aceh during 2013-2018. Mathematical analysis was carried out using the equilibrium approach with the Schaefer model. The highest catch of yellowfin tuna reached 191 tons (July) and the average CPUE for yellowfin tuna was 0.796 tons/trip with CMSY of 2,482 tons/year and EMSY of 2,765 trips/year. From 2015 to 2018, the trend of biomass continued to decline and overfishing occurred during this period.