摘要
研究于2019—2021年对长江口刀鲚(Coilia nasus)生物学、资源密度及其时空分布特征等展开调查,并结合刀鲚生产性捕捞退出前(2017—2018年)的调查结果,对长江禁捕后长江口水域刀鲚资源恢复效果进行了评估。结果显示,2021年共采集刀鲚2895尾,抽样解剖1960尾,雌雄比为1.87﹕1,平均体长和平均体质量分别为(272±32)mm和(91.4±33.4)g,较2019—2020年分别增加4.41%和37.55%,较2017—2018年分别显著增加5.84%和22.85%(P<0.05);平均丰满度系数为0.44±0.10,较2019—2020年增加18.28%,较2017—2018年增加12.82%(P>0.05)。2021年日均调查尾数N_(B)和重量W_(B)分别为170尾/d和15.56 kg/d,较2019—2020年分别增长1.09倍和1.48倍;单网调查尾数N_(t)和重量W_(t)分别为50尾/网和4.56 kg/网,较2019—2020年分别增长1.24倍和1.69倍,资源密度呈逐年上升趋势。2020年和2021年长江口刀鲚的洄游时段主要集中在3—4月,较2019年洄游高峰期提前,深水水域资源密度显著高于浅水水域(P<0.05)。研究结果表明,受前期过度捕捞的影响,加之长江口其他渔业生产尚未全部退出,2019年刀鲚专项捕捞退出后,刀鲚资源并未立即出现恢复趋势。自2021年1月1日起,长江流域重点水域全面禁捕及长江口禁捕管理政策的实施,极大减轻了刀鲚捕捞压力,长江口刀鲚种群生物学规格和资源密度均显著回升,资源恢复趋势良好,突出了长江禁捕效果的显著性。建议针对刀鲚等代表性洄游物种开展长期跟踪监测,掌握长江禁捕期间其资源特征及变动趋势,支撑长江禁捕效果评估及生物完整性评价。
Estuarine tapertail anchovy(Coilia nasus)is a valuable migratory fish species and the most representative species in the lower reaches of the Yangtze River,and its resource status have been attracted an increasing amount of attention.In order to effectively track and evaluate the recovery effects of C.nasus resource after the national fishing ban strategies,this study carried out an investigation on the spatial-temporal characteristics of biology and resource density of C.nasus in the Yangtze River estuary from 2019 to 2021 based on the survey results conducted before the withdrawal of productive fishing(2017—2018).The results showed that a total of 2895 C.nasus were collected,and 1960 were dissected in 2021,with a female to male ratio of 1.87﹕1.The mean body length of(272±32)mm and mean body weight of(91.4±33.4)g,increased by 4.41%and 37.55%compared with 2019—2020,and significantly increased by 5.84%and 22.85%compared with 2017—2018(P<0.05),respectively.The mean fatness of 0.44±0.10 was 18.28%higher than that in 2019—2020 and 12.82%higher than that in 2017—2018(P>0.05).In terms of resource density,the mean daily catch number(N_(B))and weight(W_(B))in 2021 were 170 ind./d and 15.56 kg/d,1.09 times and 1.48 times higher than that in 2019—2020,respectively.The number(N_(t))and weight(W_(t))of single net were 50 ind./net and 4.56 kg/net,1.24×and 1.69×increase compared with 2019—2020,respectively,and the resource density showed an increasing trend from 2019 to 2021.The migration time of C.nasus mainly occurred in March and April in 2020—2021,which was earlier than the peak of migration in 2019.The density of C.nasus in deep water was significantly higher than that in shallow water(P<0.05).Our study suggested that the recourses of C.nasus did not recover immediately in 2019 due to the influence of overfishing in the early stage and the fact that the other fishery production was not completely eliminated.Since January 1st,2021,the implementation of fishing ban in key waters of the Yangtze River a
作者
马凤娇
杨彦平
方弟安
应聪萍
徐跑
刘凯
殷国俊
MA Feng-Jiao;YANG Yan-Ping;FANG Di-An;YING Cong-Ping;XU Pao;LIU Kai;YIN Guo-Jun(Wuxi Fisheries College,Nanjing Agricultural University,Wuxi 214081,China;Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization,Ministry of Agriculture and Rural Affairs,Freshwater Fisheries Research Center,Chinese Academy of Fishery Sciences,Wuxi 214081,China)
出处
《水生生物学报》
CAS
CSCD
北大核心
2022年第10期1580-1590,共11页
Acta Hydrobiologica Sinica
基金
国家重点研发计划(2019YFD0901205)
长江口水域渔业资源调查(JC202104)
刀鲚资源状况及捕捞管理形势研究(CJBYZGL2021-24)资助。
关键词
长江禁捕
生物学特征
种群结构
资源特征
刀鲚
Fishing ban in the Yangtze River
Biological characteristics
Population structure
Resource characteristics
Coilia nasus
