渤海口虾蛄三重刺网渔获组成及其捕捞性能分析

为研究渤海口虾蛄(Oratosquilla oratoria)三重刺网的捕捞性能,以河北省昌黎县的口虾蛄三重刺网为基础,于2013年4、5、7月在河北省秦皇岛近海进行50 mm、55 mm、60 mm和65 mm 4种网目尺寸的三重刺网作业性能比较实验,并与60 mm网目单片刺网和底拖网进行渔获对比分析。结果表明:三重刺网具有捕获渔场中绝大多数渔业种类的能力,选择能力较差。春季的渔获种类19种,为渤海近岸底层种类;夏季的渔获种类19种,除了小黄鱼(Pseudosciaena polyactis)和带鱼(Trichiurus lepturus)等底层鱼类外,还有日本鲭(Scomber japonicus)和蓝点马鲛(Scomberomorus niphonius)等中上层鱼类。春季的渔获结构单一,口虾蛄占渔获量的90%以上,主要兼捕种类鲜明鼓虾(Alpheus distinguendus)占4.1%,渔获选择性较好;夏季的渔获中,口虾蛄比例在75%左右,兼捕对象主要为小黄鱼、蓝点马鲛等经济鱼类的幼鱼,对渔业资源造成一定程度的损害,但渔获选择性比底拖网好。单片刺网的选择性最好,但渔获量低,只有三重刺网渔获量的30%左右,无法满足生产要求。建议开展渤海口虾蛄的可捕产量和分区域捕捞管理研究,开发作业性能更优越的口虾蛄专业捕捞渔具。

Analysis on the the catch composition by trammel net and its fishing performance for Oratosquilla oratoria in the Bohai Sea

In order to study the fishing performance of trammel net for Oratosquilla oratoria in the Bohai Sea, fishing selectivity tests were conducted with trammel nets with four different mesh sizes of 50,55,60 and 65 mm based on the prototype of fishing gears in Changli County,Hebei Province during April,May and July of 2013 in the coastal waters near Qinhuangdao,and were compared with the results of the catches by the 60mm-mesh single gillnet and bottom trawl net at the same time.The results showed that the trammel net could catch nearly all of the species inhabiting in the fishing ground,indicating the poor selection capability.There were 19 species captured in the spring,all of which were coastal demersal.While in the summer there were 19 species which included demersal fishes,such as Pseudosciaena polyactis and Trichiurus lepturusd emersal etc.,and pelagic fishes,such as Scomber japonicus and Scomberomorus niphonius etc.as well.The catch composition was relatively simple in the spring with over 90% of Oratosquilla oratoria,and the main bycatch Alpheus distinguendus accounted for 4.1%.While in the summer,the Oratosquilla oratoria proportion dropped to about 75% of total catch,and most of bycatch were juveniles of Pseudosciaena polyactis and Scomberomorus niphoniu,which meant some damages made to fishery resources.By comparison,the selection performance of trammel net was better than that of trawl net,and simple gillnet was the best,but its catch amount was only 30% of trammel net,which couldn’t meet the needs of commercial fishing.It was suggested that further studies should focus on the maximum sustainable yield (MSY)of Oratosquilla oratoria and corresponding fishery management in the Bohai Sea,and try to design the professional gears with better fishing performance.