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

在短命的鱿鱼中，招募的成功很可能取决于产卵和育苗场的物理和生物环境。在自然栖息地没有观察到卵团。2000-2002年，利用MOCNESS和ROV研究了日本海域太平洋对虾的卵团和卵旁分布。2000年11月，在冲绳群岛外大陆架对马洋流的两个站观测到了胶状卵团。它们发生在跃层(深度分别为75m和95m)内，温度约为18℃，适合胚胎发育。孵化后，副鱼体可能会上升到表层，在那里它们会被带到对马流的会聚锋区。自20世纪80年代末以来，太平洋对虾的年渔获量显著增加，最近的渔获量与20世纪60年代持平。在1988年前的冷水期，东中国海区太平洋对虾冬季产卵区在成鱼种群减少时缩小；1989年后暖水期成鱼种群增加时，日本海和东中国海的秋季和冬季产卵区扩大并重叠。当混合层深度(MLD)浅于底部深度时，卵块孵化的成功率较高。我们研究了1980-2000年2月中国东海冬季产卵种群的年渔获量与风速和气温的关系，以确定一系列平静温暖的冬季如何促进与MLD变化相关的种群增长。从20世纪80年代中期到90年代中期，在弱风速和暖空气温度的十年中，年渔获量显著增加，这表明冬季风应力的强度影响了太平洋对虾冬季产卵种群的波动。

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.