Catch performance of coastal squid jigging boats using LED panels in combination with metal halide lamps

Squid attracting light systems consisting of low power light emitting diode panels (LEDs) and conventional metal halide lamps (MHs) were tested to describe the influence of combinations of LEDs and MHs on squid catch. Fishing trials using LEDs (9. kW) and different numbers of MHs were carried out in August and September 2009 targeting two squid species: (1) Japanese common squid Todarodes pacificus in northern waters of the Sea of Japan (off Hokkaido) by 4 coastal squid jigging boats (19 gross tonnage) and (2) swordtip squid Photololigo edulis in western waters (off Iki) by 5 boats of the same class. Catches of both species tended to increase with the number of MHs. Generalized Linear Model analysis revealed that in addition to the number of MHs, the catch amount was influenced by fishing power (ability) of boat and by the monthly variation of squid abundance (only for P. edulis off Iki). The expected catch (number of boxes) was not proportional to the number of MHs. The largest catch was expected for P. edulis off Iki by using LEDs with 24 MHs. The optimal combination of LEDs and MHs for T. pacificus off Hokkaido was less clear because the combination with 36 MHs had the largest positive effect on the catch; this was the maximum number MHs used

Fuel reduction in coastal squid jigging boats equipped with various combinations of conventional metal halide lamps and low-energy LED panels

Application of the low-energy light emitting diode (LED) is considered as a possible measure for fuel saving in the squid jigging fishery. We monitored fuel consumption of 14 coastal squid jigging boats ranging in size from 6.6 to 19. gross tons (GT) operating in the northern and western waters of the Sea of Japan in 2009-2011. In summer in the northern waters, squid boats of 19. GT consumed approximately 900. l in one operation that lasted from the afternoon to the next morning and 54% of the fuel was used during jigging with 53 conventional metal halide lamps (MHs) of 159. kW in total. In winter in the western waters, the total amount of fuel consumed in conventional operations of the 6.6-16. GT boats was less, but fuel consumption during jigging with lamps accounted for 70-78% of the total consumption due to close fishing grounds. The relationship between fuel consumption (l) and energy (kW. h) during jigging with lamps was expressed as a linear regression containing effects of the boat size and the inherent character of each boat. Fuel consumption rate decreases on average 0.28. l/kW. h by using LEDs with a reduced number of MHs. When 9. kW LEDs were employed with 24. MHs for 19. GT boat in the western water in summer, 24% fuel saving was estimated

Decision-making of net shooting based on gathered fish school size in a coastal purse seine fishery

中型まき網漁業の灯船のスキャニングソナー画像を解析して，魚群反応の画素数から漁獲結果を予測する実験式を得た。この式を用いて集魚中の魚群に投網した場合に期待される漁獲量（期待漁獲量）を算出し，投網したときと投網しなかったときの期待漁獲量を比較したところ，期待漁獲量の増加とともに投網する確率が高くなった。漁労長は期待漁獲量が 1.5 トン以上の集魚で必ず投網し，50% の確率で投網を行う期待漁獲量は 1.3 トンであった。期待漁獲量が 1.3 トンと 1.5 トン以上の集魚回数はそれぞれ全体の 32% と 24% であった。An empirical formula expressing the relationship between catch amount and number of pixels of the fish echo displayed in the scanning sonar prior to net shooting was obtained in the coastal purse seine fishery with fishing lights that targets Japanese anchovy Engraulis japonicus. By using this formula, we compared the expected catch amounts of fish abandoned at the end of the luring process with the expected catch amounts of fish at which the fishing master decided to shoot the net. The fishing master always decided to capture a school when the expected amount from the sonar display exceeded 1.5 tons. The probability of net shooting was expressed by a logistic function of expected catch amount. The net was shot at 50% probability when a catch of more than 1.3 tons was expected. The number of luring processes that satisfied the expected amount of over 1.5 tons accounted for only 24% of the total number of luring processes. Thus, the present style of fishing depends on many attempts to lure fish by 3 lighting boats. Cost-saving measures such as energy- and labor-saving technology should be considered to allow for fluctuations in the abundance of E. japonicus, steady increase of fuel prices, and shortage of labor that are expected in the future