Spesifikasi dan Identifikasi Hasil Tangkapan Garok Rajungan di Pelabuhan Perikanan Pantai (PPP) Bondet Kabupaten Cirebon, Jawa Barat

Crayfish (Portunus pelagicus) is the leading export commodity of Indonesian fishermen. The increasing demand for exports and high selling prices have made fishermen at the Bondet Beach Fishing Port, Cirebon Regency, use garok crabs to maximize their catch. The purpose of this study was to identify tool specifications, catch yields, selectivity and productivity of garok crab fishing gear operated at the Bondet Coastal Fishery Port, Cirebon Regency, West Java. The research was carried out in April – June 2021. The method used was a case study method with quantitative descriptive analysis to determine the specifications of the tools and catches taken by interviewing fishermen. The results showed that the crab claws were included in the dredge gear category. Its components consist of body mouth, garok, frame, nets, and ropes of various sizes. The main catch of garok crab in Cirebon Regency consists of small crab (Portunus pelagicus), and by-catch in the form of shellfish, shrimp, cuttlefish, and demersal fish, with a total of 14 species. This tool is classified as non-selective because of the small size of the bag mesh construction (30 mm) so that this tool catches many species with large and small size fish caught. The average catch obtained from 5 trips was 23.8 kg, with the lowest catch on the 2nd trip, which was 19.7 kg and the highest on the 5th trip, which was 31.3 kg, while the average sweep area was 0.0040 km2 with an average productivity of 3.97 kg/hour and the highest catch rate value was obtained on the 5th trip, which was 5.21 kg/hour, while the lowest catch rate was found on the second trip, which was 3.28 kg/hour.

Laboratory and Greenhouse Performance of Five Commercial Light Traps for Capturing Mosquitoes in China

ABSTRACT Mosquito light traps for household use are popular because they are small, cheap, user friendly, and environment friendly. At present, there are many variations and specifications of mosquito traps intended for household use on the market. The light traps claim they are powerful, but research and evaluation are lacking. Key parameters such as capture rates in the laboratory and field of 5 popular mosquito traps were evaluated as intended for household use. This study found that in the laboratory experiments, the capture rate of the mosquito traps selected was between 34.7% and 65.0%. Field tests in greenhouses found that the 5 mosquito traps had high catch rates for Culex quinquefasciatus. The percentage of Cx. quinquefasciatus, Aedes albopictus, Anopheles sinensis, and other flying insects captured was 51.76%, 25.29%, 14.12%, and 8.82%, respectively. There was no significant difference in the capture rate of Ae. albopictus and An. sinensis by the 5 mosquito traps in the greenhouse, but a significant difference in the catch rate of Cx. quinquefasciatus. The analysis showed that the fan speed and design of the air guide of the traps are important factors that affect the mosquito catch rate and that the ultraviolet wavelength (395–400 nm) used by the traps did not impact mosquito catch rates. Therefore, the mosquito traps intended for household use can be improved by adjusting the fan speed and optimizing the air guide.

Using catch-per-unit-effort data to solve spatial problems in Orange Roughy abundance estimates

<p>This thesis describes a thorough analysis of the Andes Complex orange roughy fishery, which started in 1991 and continues to date. The Andes Complex orange roughy fishery displays a rapid initial decline in catch rate, followed by a prolonged period of relatively stable catch rate. This trend is the classic feature of a hyperdepletion catch rate. The trends in the observed Andes Complex orange roughy catch rates were explored through the development of eight modified Schaefer Surplus Production Models (SPM). Each model applied a hypothesis about a mechanism catalysing the observed trend of the fishery. The SPM was modified by either adding new information to the model, or an additional parameter. The fits of the modified models were optimised to elucidate values of unknown parameters in the SPM, and these were used to create estimated abundance indicies for each model. Then I compared each index to the observed abundance index (catch rate), derived following an Exploratory Analysis. The best candidate models, which had the smallest likelihoods, BIC values, and best visual fits, were those assuming population growth rate changed midway through the fishery, or that the population size decreased following habitat damage (from trawling).</p>

Using catch-per-unit-effort data to solve spatial problems in Orange Roughy abundance estimates

<p>This thesis describes a thorough analysis of the Andes Complex orange roughy fishery, which started in 1991 and continues to date. The Andes Complex orange roughy fishery displays a rapid initial decline in catch rate, followed by a prolonged period of relatively stable catch rate. This trend is the classic feature of a hyperdepletion catch rate. The trends in the observed Andes Complex orange roughy catch rates were explored through the development of eight modified Schaefer Surplus Production Models (SPM). Each model applied a hypothesis about a mechanism catalysing the observed trend of the fishery. The SPM was modified by either adding new information to the model, or an additional parameter. The fits of the modified models were optimised to elucidate values of unknown parameters in the SPM, and these were used to create estimated abundance indicies for each model. Then I compared each index to the observed abundance index (catch rate), derived following an Exploratory Analysis. The best candidate models, which had the smallest likelihoods, BIC values, and best visual fits, were those assuming population growth rate changed midway through the fishery, or that the population size decreased following habitat damage (from trawling).</p>

Mesh Size Selectivity of Tie-Down Gillnets for the Blackfin Flounder (Glyptocephalus stelleri) in Korea

Although gillnet fisheries are increasingly common in Korea, few studies have conducted sea trials using tie-down gillnets. Here, we analyzed the mesh size selectivity using tie-down gillnets with four different mesh sizes (84, 90, 105, and 120 mm) to catch blackfin flounders. A total of 10 sea trials were conducted at depths of 100–140 m in the waters of Yangyang County, Gangwon Province, Korea, and the catching efficiency and mesh size selectivity were comparatively analyzed. The net with a mesh size of 84 mm showed the highest number of catches (373), followed by the 90-mm (363) and 105-mm (307) meshes. The results of the master curve estimation showed that the larger the mesh size, the higher the total length representing the same retention probability. Therefore, the catch rate of small fish decreased with the increasing mesh size. For the 84-mm net, the 50% selection length for small fish (total length ≤ 170 mm) was estimated at 186.9 mm, which was approximately 17 mm larger than the length limit. The results show that when using tie-down gillnets, the size of the fish caught changed according to the changes in the mesh size.

Angler and environmental influences on walleye Sander vitreus and muskellunge Esox masquinongy angler catch in Escanaba Lake, Wisconsin 2003–2015

Angler trip success and catch rates are dependent upon a fishes’ vulnerability to angling. Angling vulnerability can be influenced by angler-specific attributes (i.e., bait choice, lure size, use of a guide), and individual fish traits (i.e., boldness, aggression, stress responsiveness, and memory retention). The mechanisms that function in a fishes’ angling vulnerability, and contribute to catch rate, are likely correlated with environmental factors however, the influence of environmental factors on angling vulnerability are not well understood. We used the long-term (1946 –present) compulsory creel dataset from Escanaba Lake, WI, USA to test for interactions between angling vulnerability (i.e., angler trip success and catch rates) and environmental factors to better understand these dynamics in recreational fisheries. Our objective was to test for the influence of angler associated variables and environmental factors on open water angler trip success (i.e., catch ≥ one fish) and catch rate of walleye Sander vitreus and muskellunge Esox masquinongy during 2003–2015 using a hurdle model approach. Fishing trip success and catch rates for both species were most strongly influenced by angler-related variables (i.e., guide status, bait type, the proportion of the fish population previously caught). Environmental factors associated with lower light intensity (i.e., diel period, mean daily solar radiation, solar-Julian day interaction) had a positive influence on walleye vulnerability. Lower air temperatures and lunar position (moon overhead or underfoot) and phase (gibbous’ and full moon) also had a positive effect on walleye angling. Muskellunge trip success and catch rate were positively influenced by light metrics (i.e., diel period and mean daily solar radiation) and increased with air temperature. Lunar variables (position and phase), as well as wind speed and direction also influenced muskellunge angling vulnerability. A better understanding of the influence of environmental factors on angling vulnerability is an important component of fisheries management as management goals focus on balancing fish populations and creating satisfactory catch rates to enhance the angling experience. Our results suggest that angler-specific variables, light, temperature, lunar, and weather conditions influenced species-specific angling vulnerability for walleye and muskellunge.

KOMPOSISI HASIL TANGKAPAN PERIKANAN PAYANG DAN BAGAN TANCAP SEBELUM REKLAMASI TELUK JAKARTA (GIANT SEA WALL)

Payang merupakan alat tangkap dengan laju tangkap relatif tinggi di Teluk Jakarta, sedangkan bagan tancap dikenal kurang selektif karena hasil tangkapannya didominasi oleh ikan berukuran kecil baik jenis pelagis maupun demersal. Penelitian ini dilaksanakan dengan metode fishing experiment pada payang dan bagan tancap. Hasil penelitian menunjukkan bahwa hasil tangkapan payang dan bagan tancap didominasi oleh jenis ikan demersal namun proporsi tangkapannya tidak jauh berbeda dengan jenis ikan pelagis. Komposisi ikan hasil tangkapan payang pada Agustus dan Oktober didominasi oleh jenis ikan pelagis, sedangkan pada bulan Desember didominasi oleh jenis ikan demersal. Nilai laju tangkap payang untuk jenis ikan pelagis ditemukan tinggi pada Agustus dan Oktober disebabkan oleh dominasi ikan cekong (Sardinella lemuru) dalam jumlah besar. Komposisi ikan hasil tangkapan bagan tancap pada Mei didominasi oleh jenis ikan demersal, sedangkan pada Oktober didominasi oleh jenis ikan pelagis. Daerah penangkapan payang meliputi perairan Pulau Damar, Pulau Bendera, Muara Pecah, Muara Angke, Pulau Onrust, Pulau Putri, Kronjo, sedangkan daerah penangkapan bagan tancap terkonsentrasi di sebelah barat perairan Teluk Jakarta, sekitar Pulau Kayangan, Pulau Bidadari dan Pulau Onrust. ABSTRACT Payang, a mini danish seine, is an artisanal fishing gear that has high catchability rate. Like payang, another dominant fishing gear in Jakarta Bay, the lift net, is also known as unselective fishing gear since small fish dominate its catch. This research uses the fishing experiment method with payang and lift net to figure out the gears' catch composition and catch rate. The result shows both fishing gears predominately caught the demersal fish group, but its proportion does not much from the pelagic group. During August and October, the catch composition of payang was dominated by pelagic fish, while demersal fish was caught mostly in December. The high catch rate for pelagic fish was recorded in August and October since cekong fish (Sardinella lemuru) dominated the cath. The catch composition of lift net was dominated by demersal fish during May, while pelagic fish were mostly captured in October. Payang’s fishing ground includes Pulau Damar waters, Pulau Bendera, Muara Pecah, Muara Angke, Pulau Onrust, Pulau Putri, and Kronjo, while the lift net dominates the western part of part of Jakarta Bay including Pulau Kayangan, Pulau Bidadari, and Pulau Onrust.

Laboratory and Field Performance of Five Cheap Commercial Light Traps for Capturing Mosquitoes In China

BackgroundMosquito light traps for household use are popular because they are small, cheap, user friendly, and environmentally friendly. At present, there are many variations and specifications of mosquito traps intended for household use on the market. Their labels claim they are powerful, but research and evaluation of their claims is lacking.MethodsThis article tested the key parameters, the laboratory capture rates, and the field capture rate of 5 popular mosquito traps intended for household use. ResultsThe study found that in the laboratory experiment, the capture rate of the mosquito traps selected was between 34.7%-65.0%. The analysis showed that the fan speed, and design of the air guide of the traps are important factors that affect the mosquito catch rate. Field tests in the greenhouse found that the 5 mosquito traps had high catch rates for Culex quinquefasciatus. The average percentage of Cx. quinquefasciatus, Aedes albopictus, Anopheles sinensis, and other flying insects captured every night was 51.76%, 25.29%, 14.12%, and 8.82%, respectively. There was no significant difference in the capture rate of Ae. Albopictus and An. sinensis by the 5 mosquito traps in the greenhouse, but a significant difference in the catch rate of Cx. Quinquefasciatu. ConclusionsThe ultraviolet wavelength (395-400nm) involved in the selected mosquito traps is not the main reason that affects the mosquito catching effect, but the fan speed and the air guide may be the reason for the difference in the catching effect among the five mosquito traps. Therefore, the mosquito traps intended for household use can be improved by adjusting the fan speed and optimizing the air guide.