【摘要】 为掌握网目尺寸对多锚单片张网捕捞生产量、渔获种类及渔获物规格等指标的影响,采用主网衣网目尺寸为18 mm的生产网,及主网衣网目尺寸分别为25、35、45 mm的试验网各5片,将其连接成"一"字形,在辽东湾海域进行了10网次的生产对比试验研究。结果表明:各种规格试验网的总渔获量比生产网分别减少12.81%、51.50%、60.81%,其中35、45 mm试验网的渔获量减少更为明显,但主要经济种类的渔获量并未明显减少(除虾类外);生产网(18 mm)渔获物29种,25、35、45 mm网目的试验网渔获物分别为24、17、14种,随着网目尺寸的增大,捕获种类明显减少;生产网中以中华安乐虾Eualus sinensis、葛氏长臂虾Palaemon gravieri居多,棘头梅童鱼Collichthys lucidus、斑尾刺虾虎鱼Acanthogobius ommaturus、日本蟳Charybdis japonica、口虾蛄Oratosquilla oratoria为4种网具共有的优势渔获种类,而试验网随着网目尺寸的增大,虾类被释放,且各类优势种最小体长组释放比例明显增大,幼鱼捕获量明显减少,兼捕现象得到缓解。研究表明,主网衣网目尺寸为35 mm的试验网对优势种的选择性较高,且能够为渔民获得较好的经济效益,本研究成果可为中国多锚单片张网的结构优化提供数据参考。更多还原

【Abstract】 Twenty 5 m×3.8 m multi-anchored monolithic traps with mesh size of 18 mm(control group), 25 mm, 35 mm and 45 mm were connected into a line shape, and operated in 30 miles(40°42′-40°56 N′, 121°20′-121°39′ E) from the entrance of Shuangtaizi in Liaodong Bay, China, 10 times in October 11-16, 2018 to probe into influence of mesh size on production capacity of net gear, and size and type of catch. The results showed that the total catch was reduced by 12.81% in the 25 mm trap, 51.50% in the 35 mm trap and 60.81% in the 45 mm trap compared with that in the control group, especially for the 35 mm and 45 mm test nets, without decline in the total catch of main economically important types(except shrimp). The species number of the catch was shown to be significantly reduced as the mesh size was increased, 29 species in the control trap, 24 species in the 25 mm trap, 17 in the 35 mm trap, and 14 in the 45 mm trap. Prawns Eualus sinensis and Palaemon gravieri, spinyhead croaker Collichthys lucidus, spottedtail goby Acanthogobius ommaturus, stone crab Charybdis japonica, and mantis shrimp Oratosquilla oratoria were the dominant species and shrimps were released with increase in the mesh size in the four nets, with the maximal release ratio in the smallest body length group, and significantly reduction of juvenile fish in the catch, indicating that the phenomenon of bycatch was alleviated. The findings provide a theoretical basis for the structural optimization of multi-anchored monolithic nets in China.更多还原