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Stock Fluctuations throughout Reproduction and Recruitment Process of the Japanese Common Squid, Todarodes pacificus, related to Climate Changes

与气候变化相关的日本鱿鱼 (Todarodes pacificus) 繁殖和补充过程中的种群波动

基本信息

批准号：
12460080
负责人：
SAKURAI Yasunori
金额：
$ 7.3万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

In short-lived squids, recruitment success most likely depends on the physical and biological environments at the spawning and nursery grounds. No egg masses have been observed in the natural habitat. During 2000-2002, MOCNESS and an ROV were used to examine the distribution of egg masses and paralarvae of Todarodes pacificus in the Sea of Japan. Gelatinous egg masses were observed at two stations in the Tsushima Current along the continental shelf off the Oki Islands in November, 2000. They occurred within the pycnocline (75 and 95 m depth, respectively), where temperatures were about 18℃, which was suitable for embryonic development. Upon hatching, paralarvae may rise to the surface layer, where they would be carried into the convergent frontal zone in the Tsushima Current.Annual catches of T. pacificus, have markedly increased since the late 1980s, and recent catches have equaled those of the 1960s. The winter spawning area of T. pacificus in the East China Sea shrank when adult stocks decreased during a cool regime that occurred before 1988, and that its fall and winter spawning areas extended and overlapped in the Sea of Japan and East China Sea when adult stocks increased during a warm regime after 1989. Successful hatching from egg masses was to be higher when the mixed layer depth (MLD)is shallower than the bottom depth. We examined the relationship between annual catch of the winter-spawning stock, and wind speed and air temperature in the East China Sea in February during 1980-2000 to determine how a series of calm and warm winters might promote a stock increase related to changes in the MLD. Annual catches markedly increased during a decade of weak wind speed and warm air temperature from the mid-1980s to mid-1990s, suggesting that the strength of winter wind stress affects the winter-spawning stock fluctuations in T. pacificus.

在短寿命的鱿鱼，招聘成功最有可能取决于在产卵和育苗场的物理和生物环境。在自然栖息地中没有观察到卵团。2000-2002年，利用MOCNESS和一种生物测定仪对日本海太平洋褶柔鱼卵块和卵囊的分布进行了研究。2000年11月，在对马海流沿着隐岐群岛外大陆架的两个观测站观测到胶状卵团。它们发生在密度跃层（75 m和95 m）内，温度约为18℃，适宜胚胎发育。在孵化后，尖吻鲈可能会上升到表层，在那里它们会被带到对马海流的辐合锋区。自1980年代后期以来，太平洋小渔获物显著增加，最近的渔获量已与1960年代持平。冬季产卵区为T. 1988年以前，东海太平洋柔鱼的产卵量随冷温变化而减少; 1989年以后，日本海和东海太平洋柔鱼的产卵量随暖温变化而增加。当混合层深度（MLD）比底层深度浅时，卵块的孵化成功率较高。我们研究了1980-2000年2月东海冬季产卵种群的年渔获量与风速和气温之间的关系，以确定一系列平静和温暖的冬天如何可能促进与MLD变化相关的种群增加。在20世纪80年代中期至90年代中期的弱风速和暖气温的10年中，年渔获量显著增加，表明冬季风应力的强度影响了T.太平洋。