2014年江苏省刺网渔业生产时空分布特征

基于抽样调查获得的2014年江苏省沿海刺网渔船生产数据,对江苏刺网渔业生产和渔获结构时空分布进行了初步分析。结果表明,江苏刺网渔船基本为本地近海生产,未出现远赴外地渔场生产情况;江苏中部以北近岸水域为刺网渔船主要作业渔场,而中部以南近岸水域少有渔船作业,可能是因为受航道、其它网具占用渔场、或捕捞对象分布习性等因素影响。伏季休渔前后在江苏中北部近岸水域,冬末春初在长江口渔场中部外侧水域,生产情况均相对较好,这可能与捕捞对象产卵、越冬行为相关。吕四渔场和大沙渔场是江苏刺网渔船主要作业水域,随着水温季节性变化,其生产范围会相应往北部和南部水域适当扩大;年初主要集中在吕四渔场,年末集中在大沙渔场;伏休前生产范围最广,伏休后生产范围有所收缩。另外,刺网捕捞主要渔获为价值较低的小个体鱼类和虾类,传统经济鱼类所占比例较低。由于刺网网目尺寸偏小,加上拖网、张网和多重刺网的泛滥使用,对渔业资源补充造成危害;刺网已经失去了传统上被认为是具有高度选择性的优良特征,建议管理部门重新考虑相关管理策略,开展针对各个渔业种群进行差别化精准管理研究。

Temporal and spatial distribution characteristics of gillnet fishery production of Jiangsu Province in 2014

This paper takes a preliminary analysis on the temporal and spatial distribution characteristics of gillnet fishery production in Jiangsu, based on the fishery production sampling data got from the coast of Jiangsu Province in 2014.The analysis found that almost all gill net boats were fishing in the local offshore, and there was no boat travelling further to other nonlocal fishing grounds.The area from the north to the middle of Jiangsu coast was filled with gill net boats, but there was no boat in the coast from the middle to the south.The possible reasons were related to the unavailable channel, fishing ground occupied by other fishing boats or distribution of the other special species not suitable for gillnet catching etc.Before and after the summer fishing moratorium in the northern Jiangsu coastal waters, and in late winter and early spring in the outside waters of the Yangtze River Estuary fishing ground, the fishing yield was relatively good, which may be related to marine fish biological migration cycle behavior such as spawning and overwintering.Lvsi and Dasha fishing grounds were the main areas for Jiangsu gillnet fishing, and the fishing areas were expanded to the northern and the southern waters appropriately with the flutuation of temperature in four seasons.At the beginning of year the boats mainly concentrated in Lvsi fishing ground, and at the end of year in Dasha fishing ground.Before the summer fishing moratorium the boats distributed in the widest range, and after that the range contracted to a certain extent.In addition, it was found that the main fishing object of gillnet boats was the miscellaneous small fishes and shrimps with low value, and the proportion of the traditional economic fishes was small.Above results indicated that the catches were mostly composed of species wih small individuals, so it was speculated that the mesh size of gillnet boats was too small.Going further with pervasive using of multiple gill nets, the excellent advantage characteristics of gill nets considered in tradition, high selectivity, has been lost.The gillnet boats have caused harm to the recruitment of fishery resources, and it is suggested that the administrator should reconsider the management strategies for them.The high CPUE of gillnet boat appeared in two durations, from Jan.to Feb.and from Aug.to Sep., and the catch structures of the two period were obviously different.The former was composed of shrimp and miscellaneous small fish and shrimp, and the latter included most of recruitment individuals.Gillnet catching objects appeared obviously seasonal alternation with relatively dense distribution of resources, such as shrimp (from Jan.to Mar.), Setipinna taty (from Apr.to May), crab (from Aug.to Oct.), and small yellow croaker (from Oct.to Dec.).However, miscellaneous small fish and shrimp began to appear with relatively high proportion from March to the end of year, and the area of its dense distribution changed with time.Further research on the temporal and spatial distribution of each species would help taking precise management on them.