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ウナギ標識放流個体群の水産資源学的研究

标记鳗鱼种群渔业资源研究

基本信息

批准号：
13660177
负责人：
TATSUKAWA Kenichi
金额：
$ 1.98万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

Fisheries biology of the stocked eel population with a fin clipped mark The eel stock in Japan has tendency of decrease recently. The purpose of this study is to discuss on strategies and counter plans to recover eel stocks using research results of population processes such as survival, growth, distribution and the other ecological characters of the stocked eel population.7977 fish (00 group) of some months cultured eel which were clipped off a right pectoral fin by scissors were stocked into the Monobe river, Kochi prefecture, Japan, in May, 2000. And 7989 eels (01 group) without a left pectoral fin were stocked into the same river, in May, 2001. The research water length was 7 km from a mouth of the river to an upper dam. Three wooden bait traps for, eels were set at 6 points respectively. Fishery statistics by river fishermen was used to analysis catch data. The research period was until December of 2003.Annual catch(number) of 00 group was 94,46,19,21 and the ratio to total catch … More (%) was 8.5,7.5,2.6,2.6 since 2000, respectively. The instantaneous mortality rate was about 0.5. Percent catch of annual total catch added a natural eel population in the upper water place was from 57.2 to 70.2 for four years. However the percent catch of only stocked eel was from 31.6 to 514. The range of total length of eel was 28.9 to 40.5 cm in 2000 and 36.4 to 51.3 cm in 2003. The average increment was 8.4 cm for three years. The condition factor showed very wide range, but had a tendency of increase year by year. Percent yellowish body, color was from 15.7 in 2000 to 90.0 in 2003. This means stocked eels may have naturalized in the river. Percent female was from 5.3 to 95.0 since 2000. 01 group was caught only 8 fish in 2003. This resulted limitation of fishing gear to depend on eel length.Some conclusions were as follows, Some months cultured eel could dwell and survive in a river at least for four years. It was considered that the half of stocked eels could eat natural foods, grow, become fat and make yellowish body by naturalization. It is expected that the eel stock might increase by stocking of young eels. However rehabilitation of some suitable habitats in a river for an eel population must be maintained higher survival rate and also growth rate for eels. Less

带剪鳍记号的放养鳗鱼种群的渔业生物学最近日本的鳗鱼种群有减少的趋势。本研究的目的是利用种群过程的研究成果，探讨恢复鳗鱼种群数量的策略和对策。2000年5月，在日本高知县Monobe河放养了7977尾(00组)几个月养殖的鳗，用剪刀剪断了右胸鳍。2001年5月，7989条没有左胸鳍的鳗鱼(01组)被放养到同一条河中。研究水域从河口到上游大坝的长度为7公里。三个木制诱饵分别设在6个点。利用河流渔民的渔业统计数据分析渔获量数据。研究期间至2003年12月，00组年渔获量为94，46，19，21个，占总渔获量…的比例2000年以来分别为8.5、7.5、2.6、2.6。瞬时死亡率约为0.5。上游天然鳗鱼种群占年新增渔获量的百分比连续4年在57.2~70.2之间。然而，仅放养鳗鱼的渔获量百分比为31.6-514。2000年鳗鱼全长为28.9~40.5 cm，2003年为36.4~51.3 cm。3年平均生长量为8.4 cm。条件因子变化范围很广，但有逐年增加的趋势。颜色从2000年的15.7%到2003年的90.0%。这意味着放养的鳗鱼可能已经在河里归化了。自2000年以来，女性比例从5.3%上升到95.0%。01组2003年仅捕捞8尾鱼。这导致了渔具只能依赖鳗鱼的长度的限制。一些结论如下：养殖的鳗鱼在几个月的时间里可以在河里生活和存活至少四年。人们认为，一半的放养鳗鱼可以食用天然食物，生长、发胖，并通过归化使身体变黄。预计通过放养幼鳗，鳗鱼库存可能会增加。然而，在河流中恢复一些适合鳗鱼种群的栖息地，必须保持较高的成活率和鳗鱼的生长速度。较少