使用套网法在海州湾海域进行了坛子网3种网目尺寸(30、35和40 mm)的网囊网目选择性试验.在分析渔获物组成的基础上,基于Logistic选择模型和数量生物量曲线(Abundance-biomass comparison curves,AIBC曲线)法,获得了渔获物中主要经济品种小黄鱼(Pseudosciaena pol yactis)、鹰爪虾(Trach ypenaeus curvirostris)和口虾蛄(Oratosquilla oratoria de Haan)的选择性曲线和ABC曲线.结果表明,坛子网网囊网目尺寸为30、35和40 mm时,小黄鱼的50％选择体长(L50)分别为7.920、9.503和11.229 cm,选择范围(SR)分别为1.975、2.306和3.775 cm;鹰爪虾的(Ls0)值分别为5.400、5.901和7.404cm,其SR值分别为1.283、1.376和1.709 cm;口虾蛄的Ls0值分别为7.844、8.324和9.602 cm,其SR值分别为2.680、2.719和2.973 cm;随着网目尺寸逐渐增大,小黄鱼、鹰爪虾和口虾蛄选择性指标50％选择体长(L50)和选择范围SR值也随之逐渐增大.3种坛子网试验网囊内ABC曲线W值均小于0,表明针对海州湾目前整体生物群落,网囊网目尺寸需要进一步放大.本研究结果可为中国黄海区渔业资源可持续发展及张网网囊最小网目尺寸的确定提供科学参考.
A Study on the Selectivity of Codend Mesh of Tanzi Net in Haizhou Bay
Tanzi net is a kind of double stake stow net.It is a traditional fishing gear in Haizhou Bay.On account of its lower cost,lower energy consumption and stable output,Tanzi net fishing has already become an important method.Because of its small mesh size of codend,a lot of young fish or shrimp are often caught.Such shortage has seriously negative influenced the offing fish resource.So it is necessary to carry out study on the selectivity of Tanzi net.It is the basal work of the study on the minimal mesh size of Tanzi net in Haizhou Bay.Referred to relevant research data,there is seldom studies on the size selectivity of stow net in Haizhou Bay.The selectivity of codend mesh of Tanzi with several mesh sizes (30,35 and 40mm) has been tested by using the cover-net method in Haizhou bay.Because the AIC value of the Logistic model is relatively smaller than that of other models and the model is the conventional used in researches on the selectivity of fishing gear,the Logistic model was selected as the selectivity model of this experiment.Also,abundance-biomass comparison curve (ABC curve) and biomass spectrum method were applied to analyzing the data too.Based on the analyses of the catches composition and the Logistic equation model and ABC curve,the authors obtained W value and the selectivity curve of the main economic varieties,P.polyactis,T.curvirostris and O.oratoria de Haan.Parameters of selectivity were estimated with the maximum likelihood method.The result showed that the 50％ selection length,Ls0,of P.polyactis was 7.920,9.503 and 11.229 cm,and the selection range (SR) was 1.975,2.306 and 3.775 cm,respectively,when the mesh size was 30,35 and 40 rm;the L50of T.curvirostris was 5.400,5.901,7.404 cm and the SR was 1.283,1.376 and 1.709 cm,respectively,when the mesh size was 30,35 and 40 mm;the L50 of O.oratoria de Haan were 7.844,8.324 and 9.602 cm,and the SR was 2.680,2.719 and 2.973 cm,respectively,when the mesh size was 30,35 and 40 mm.Enlarging the mesh size of TanZi net increased the L50 and the SR of P.polyactis,T.curvirostris and O.oratoria de Haan.The W value of the three codend meshes was less than 0 in terms of the whole biological community of the Gulf of Haizhou at present,which implied that mesh size needs to be further enlarged.Based on the database,the selectivity of the Tanzi net fishery is poorer,the amount of by-catch is too large.It was suggested to take some feasible modification on fishery nets for protecting fishery resource.The research results were applicable in the fishery resources sustainable development in the Yellow Sea region and also provided the scientific reference to the minimum mesh size of the codend net.
Tanzi netcodend mesh sizeselectivitycovered net methodABC curve
国家科技期刊平台
NSTL
万方数据
维普
