南海北部拖网35.2与30.3mm方目网囊渔获选择性比较  

Comparison and analysis on catch selectivity of square mesh codends between 35.2 and 30.3 mm of trawl in northern South China Sea

作　　者：张旭丰[1] 张鹏[1] 杨吝[1] 谭永光[1] 

机构地区：[1]中国水产科学研究院南海水产研究所,广东广州510300

出　　处：《南方水产》2007年第2期49-54,共6页South China Fisheries Science

基　　金：农业部渔业局水产行业标准化项目(2000230)

摘　　要：根据1997年10月和2000年11～12月的拖网网囊网目选择性试验资料，对网目内径35．2mm方目和30．3mm方目网囊的渔获选择性进行了比较和分析。对比试验结果表明，35．2mm方目网囊渔获尾数总逃逸率为39．28％、重量总逃逸率为16．18％，高于30．3mm方目网囊的28．40％和7．47％，35．2mm方目网囊的渔获选择性有所提高；2种规格方目网囊及其套网中出现的渔获种类较为相似，具有释放鱼类种类少、数量低的共同特点，且在渔获选择性能上的差别还不明显，对渔获种类数量的释放效果都相当有限；作为优势释放种类，大头狗母鱼、条尾绯鲤和多齿蛇鲻在2种规格方目网囊中的尾数逃逸率和重量逃逸率分别在42．9％～65．8％和24．2％～45．0％之间；其中条尾绯鲤和多齿蛇鲻的50％选择体长均未达到最低可捕标准。总体来看，2种规格方目网囊对渔获的总体释放效果还不理想，要实现负责任捕鱼，需进一步放大拖网方目网囊的网目尺寸。Based on mesh selectivity data of double bottom trawl codend tested in the offshore waters of northern South China Sea in October 1997 and from November to December 2000, catch selectivity of square mesh codends between 35.2 and 30. 3 mm of trawl was compared and analysed. The results are as follows. （ 1 ） Because the total escape rates of 35. 2 mm square-mesh codend for catch （39. 28% in number and 16. 18% in weight） are higher than that of 30. 3mm square-mesh codend for catch （28.40% in number and 7.47% in weight）, catch selectivity of 35.2 mm square mesh codend is slightly better than that of 30.3 mm square mesh codend. （2） The main species in 35.2 mm square mesh codend and its cover net are mostly the same as 30. 3mm square mesh codend and its cover net, and there are lesser and fewer in commercial species and its numbers in their cover nets. （3） The escape rates of Trachinocephalus myops, Upeneus bensasi and Saurida tumbil as dominant species released are 42. 9% - 65.8% in number and 24. 2% - 45.0% in weight respectively in 35.2 and 30. 3 mm square-mesh codends, and the 50% selection lengths （ L0. 5 ） caught S. tumbil and U. bensasi are smaller than their minimum fishable size. It is considered that there are no distinct difference on catch selectivity of square mesh codends between 35.2 and 30. 3 mm of trawl and satisfactory and responsible fishing can be achieved no other than enlarging mesh size of the codend of bottom trawl based on the comprehensive analysis.

关 键 词：网目选择性 方目网囊 拖网渔获 

分 类 号：S972.13[农业科学—捕捞与储运]