上海奉贤区定置张网渔船产值变动分析

为研究上海奉贤区渔民收入水平及变化,利用曲线回归、聚类分析等方法对2009年5月-2012年10月奉贤区定置张网渔船年产值及单位投网数产值(VPUE)等监测数据进行分析。结果显示:渔船产值逐年升高,2009年产值为20.57万元,2012年提高到31.35万元,增幅达到52.4%;VPUE呈现逐年增高之势,2009年为44.59元/网,2012年提升到61.98元/网,增幅接近40%。利用曲线回归估计法对产量与VPUE的相关性进行分析,发现两者无显著相关性(P=0.5010.05),而产值与VPUE具有显著相关性(P=0.0080.05),其关系可以用公式y=33.812lnx+5.3808表达。VPUE季节变化中,春季与夏、秋季均无显著性差异(P=0.0930.05,P=0.1650.05),而夏季与秋季存在显著性差异(P=0.0080.05)。研究表明,渔民不能盲目地以提高总产量为目标来寻求经济效益最大化,而是应该提高渔获物中经济鱼类所占比例和产量,这不仅能够促进渔民增产增收,而且对于保护幼鱼资源,促进渔业资源的合理恢复也具有重要意义。

Analysis of variation of yield value by set net fishing boat in Shanghai Fengxian District

Sea area along Fengxian District is located in the northern Hangzhou Bay,where the migratory fish such as Coilia mystus,Pampus argenteus, etc must pass through for spawning and feeding migration.Set net is the only way for fishing in this sea area,so studying on the variety of yield and yield value from a set net fishing boat is very helpful to evaluate the current fishing income on the sea along Fengxian District.As no study has been carried out investigating the variation of yield value and value per unit effort (VPUE) from set net fishing boat on the sea along Fengxian District, the methods of curve estimation and cluster analysis were applied in this study to evaluate the variation of yield value and VPUE,which may be helpful to find out the relationship among yield, yield value and VPUE from a set net fishing boat in Fengxian District(from May 2009 to October 2012).The results indicated that yield value and VPUE from set net fishing boat increased year by year,yield value and VPUE in 2009 was 205.7 thousand yuan and 44.59 yuan per net respectively,and in 2012 increased to 313.5 thousand yuan and 61.98 yuan per net respectively.Yield and VPUE had no significant correlation (P=0.501>0.05),but yield value and VPUE had significant correlation(P=0.008<0.05),and the relationship between yield value and VPUE can be expressed as following equation: y= 33.812lnx + 5.3808.In seasonal variation of VPUE,there was no significant correlation between spring and summer(P=0.093>0.05),there was also no significant correlation between spring and autumn(P=0.165>0.05),but there was significant correlation between summer and autumn(P=0.008<0.05).The research showed that it was inadvisable for fishman to pursue profits by maximizing total catch and they should increase yield and proportion of commercial fishes,which can not only increase fishing income,but also promote protection of juvenile fish and recovery of fishery resources.