Monthly fishery survey data of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea from2003 and 2013 were employed to evaluate the variation in the resource distribution and biological character...Monthly fishery survey data of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea from2003 and 2013 were employed to evaluate the variation in the resource distribution and biological characteristics（especially body length and sex ratio） in the population on a decadal scale.The results indicated that the small yellow croaker migrated from the Shawai fishing ground to the Dasha fishing ground in spring and was mainly distributed in the central and western parts of the Dasha fishing ground in April and May.Larimichthys polyactis in the Dasha fishing ground migrated eastward to offshore wintering grounds in autumn and reached the central Dasha fishing ground in October and November.The small yellow croaker entered the western waters of the Shawai fishing ground in winter.A large number of age 0＋ fish occurred in the Shawai and Jiangwai fishing grounds in October of 2003 and 2013.The body lengths of the spawning stock and wintering stock in 2013 were larger than those in 2003,and the monthly sex ratios（female to male） were significantly less than 1 in both years.The monthly distribution of this fish in the southern Yellow Sea was consistent with a previous finding that ＂the stock migrated between the wintering grounds in the west of Jeju Island and the Lüsi spawning grounds＂ but tended to move more northward,with the spawning grounds extending outward.In the past decade,body length variation experienced a decline after an increase,rather than a steady decrease.The sex ratio in the single-stick stow net showed a tendency to increase over the decade,but was either less than or more than 1 depending on the fishing gear;therefore,further studies should be conducted to determine the sex structure.展开更多
2020年我国伏季休渔期间中国毛虾限额捕捞试点在黄海海州湾实施,2021年该限额捕捞项目继续实施,在此背景下探究夏季海州湾中国毛虾资源分布对其限额捕捞精细化管理至关重要。首先基于2021年海州湾中国毛虾限额捕捞期间北斗渔船监控系统(...2020年我国伏季休渔期间中国毛虾限额捕捞试点在黄海海州湾实施,2021年该限额捕捞项目继续实施,在此背景下探究夏季海州湾中国毛虾资源分布对其限额捕捞精细化管理至关重要。首先基于2021年海州湾中国毛虾限额捕捞期间北斗渔船监控系统(Vessel monitoring system,VMS)数据提取得到各毛虾张网渔船所有捕捞网位点及其捕捞努力量,然后运用具有噪声的密度聚类(Density-based spatial clustering of application with noise,DBSCAN)算法进一步识别含有捕捞产量的网位点,从而探究夏季海州湾中国毛虾资源分布格局。结果显示,含有产量的网位点识别率为97.18%,表明DBSCAN算法能精准识别含有产量的捕捞网位点。含有产量的网位点共有898个,空间上呈聚集性分布。依据捕捞努力量情况探究得到中国毛虾资源主要分布在120°00′E~120°15′E,34°43′N~34°48′N和119°47′E~119°53′E,34°36′N~34°43′N。本研究思路可作为其他渔业捕捞活动中运用VMS数据提取含产量捕捞网位点的科学参考。展开更多
基金The Natural Science Foundation of Jiangsu Province of China under contract No.BK20140438the Special Fund for the Fishery Resource Survey Project of East China Sea Region by the Ministry of Agriculture+1 种基金the Jiangsu Innovative Experiment Project for Postgraduate Students of China under contract No.CXZZ13_0275the Jiangsu Science and Technology Support Program of China under contract No.BE2012422
文摘Monthly fishery survey data of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea from2003 and 2013 were employed to evaluate the variation in the resource distribution and biological characteristics（especially body length and sex ratio） in the population on a decadal scale.The results indicated that the small yellow croaker migrated from the Shawai fishing ground to the Dasha fishing ground in spring and was mainly distributed in the central and western parts of the Dasha fishing ground in April and May.Larimichthys polyactis in the Dasha fishing ground migrated eastward to offshore wintering grounds in autumn and reached the central Dasha fishing ground in October and November.The small yellow croaker entered the western waters of the Shawai fishing ground in winter.A large number of age 0＋ fish occurred in the Shawai and Jiangwai fishing grounds in October of 2003 and 2013.The body lengths of the spawning stock and wintering stock in 2013 were larger than those in 2003,and the monthly sex ratios（female to male） were significantly less than 1 in both years.The monthly distribution of this fish in the southern Yellow Sea was consistent with a previous finding that ＂the stock migrated between the wintering grounds in the west of Jeju Island and the Lüsi spawning grounds＂ but tended to move more northward,with the spawning grounds extending outward.In the past decade,body length variation experienced a decline after an increase,rather than a steady decrease.The sex ratio in the single-stick stow net showed a tendency to increase over the decade,but was either less than or more than 1 depending on the fishing gear;therefore,further studies should be conducted to determine the sex structure.
文摘2020年我国伏季休渔期间中国毛虾限额捕捞试点在黄海海州湾实施,2021年该限额捕捞项目继续实施,在此背景下探究夏季海州湾中国毛虾资源分布对其限额捕捞精细化管理至关重要。首先基于2021年海州湾中国毛虾限额捕捞期间北斗渔船监控系统(Vessel monitoring system,VMS)数据提取得到各毛虾张网渔船所有捕捞网位点及其捕捞努力量,然后运用具有噪声的密度聚类(Density-based spatial clustering of application with noise,DBSCAN)算法进一步识别含有捕捞产量的网位点,从而探究夏季海州湾中国毛虾资源分布格局。结果显示,含有产量的网位点识别率为97.18%,表明DBSCAN算法能精准识别含有产量的捕捞网位点。含有产量的网位点共有898个,空间上呈聚集性分布。依据捕捞努力量情况探究得到中国毛虾资源主要分布在120°00′E~120°15′E,34°43′N~34°48′N和119°47′E~119°53′E,34°36′N~34°43′N。本研究思路可作为其他渔业捕捞活动中运用VMS数据提取含产量捕捞网位点的科学参考。
