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

对于寿命较短的鱿鱼来说，招募成功与否很可能取决于产卵地和育儿地的物理和生物环境。在自然栖息地没有观察到卵团。在2000-2002年期间，利用MOCNESS和ROV对日本海太平洋蟾蜍的卵群和幼虫的分布进行了调查。2000年11月，在冲绳岛大陆架附近对马流的两个站点观测到胶状卵团。它们分别发生在75 m和95 m深的背斜层内，温度约为18℃，适合胚胎发育。在孵化后，幼虫可能上升到表层，在那里它们将被带到对马流的辐合锋面区。太平洋T. pacific ificus的年捕获量自20世纪80年代末以来显著增加，最近的捕获量与20世纪60年代的捕获量相当。1988年以前，在较冷的气候条件下，成鱼种群数量减少，东海冬产卵区缩小；1989年以后，在较暖的气候条件下，成鱼种群数量增加，东海和日本海冬产卵区扩大并重叠。当混合层深度小于底部深度时，蛋块孵化成功率较高。研究了1980-2000年2月东海风速和气温与冬季产卵种群年捕获量的关系，以确定一系列平静和温暖的冬季如何促进与MLD变化相关的种群增加。在20世纪80年代中期至90年代中期弱风速和暖空气温度的10年间，年捕鱼量显著增加，表明冬季风胁迫的强度影响了太平洋柽柳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.