"Ecoogical Study on sustainabel fisheries management based on the ecosystem conservation"

太平洋鲑鱼（Oncorhynchus spp.）生物量的变化表明北太平洋有30- 40年的周期性，与长期气候条件相一致。本文利用Ricker’s招募t曲线的替代水平估计了北太平洋红鲑、红鲑和粉鲑的承载能力K，并定义了剩余承载能力（RCC）： RCC=（承载能力-生物量）/（承载能力）x100。在种水平上，阿留申低压指数（ALPI）与承载力呈显著正相关。在种群水平上，影响承载能力的因素，如繁殖制度（如早期海洋生物时期的存活率和海温）和孵化技术，在北海道鲑鱼种群中存在差异。在北海道鲑鱼种群中，RCC与体型呈显著正相关，与成熟年龄呈显著负相关。尽管孵化场种群的生物量显著增加，但20世纪90年代的大马哈鱼种群数量比20世纪30年代减少了50%。野生种群和孵化场种群之间的生物相互作用应是基于生态系统水平的太平洋鲑鱼生产可持续管理的重要考虑因素。在1994-2000年初夏期间，通过胃内容物和碳氮稳定同位素的分析，研究了气候事件对阿拉斯加湾中部近海太平洋鲑鱼摄食生态和营养动态的影响。除大马哈鱼外，其他鲑鱼的主要猎物为gonatiid squid（主要为Berryteuthis anonychus）。在1997年的厄尔尼诺事件和1999年的拉尼娜事件期间，除亚北极洋流中的长鳍鲑鱼外，所有太平洋鲑鱼的饮食中鱿鱼的数量急剧减少，而鲑鱼的饮食从凝胶状浮游动物转变为更多样化的浮游动物物种。a - 13c和δ15N分析表明，1999-2000年，所有鲑鱼物种都处于同一食物网分支。我们假设，公海鲑鱼通过改变营养水平内或营养水平之间的饮食来适应气候引起的猎物资源变化。由于城市化的加速和自然河岸生态系统的恶化，如大坝建设、栖息地破坏和人工孵化场等，野生产卵鱼（太平洋鲑鱼）的减少导致了营养损失（少营养化）和随之而来的低生产力对生态系统生物多样性和生产力的影响，近年来引起了研究人员的兴趣。在日本，大马哈鱼已经通过孵化场计划大量繁殖，而大量野生太平洋大马哈鱼由于城市化和河岸生态系统的恶化而几乎灭绝。溯河鱼类是维持河岸生态系统生产和生物多样性的关键物种。为了实现河岸生态系统的可持续保护管理，野生鲑鱼种群、物质循环系统和自然河流的恢复是日本面临的重要问题。少

The change in biomass of Pacific salmon (Oncorhynchus spp.) indicates a 30- or 40-year periodicity in the North Pacific Ocean coinciding with long-term climate conditions. We estimated the carrying capacity (K) of sockeye, chum, and pink salmon in the North Pacific Ocean using the replacement level of the Ricker's recruitment t curve, and defined residual carrying capacity (RCC): RCC=(Carrying capacity-Biomass)/(Carrying capacity)x100.A significant positive correlation between Aleutian low pressure index (ALPI) and the carrying capacity was observed at the species level. Factors affecting carrying capacity at the population level, such as reproductive regimes (e.g. survival rate and sea surface temperature (SST) in the early marine life period and hatchery technology), differed by population in Hokkaido chum salmon. The RCC was significantly positively correlated with body size and negatively related to age at maturity in Hokkaido chum salmon populations. The biomass of chum salmon wil … More d populations in the 1990s decreased 50% below that of the 1930s, despite the significant increases in the biomass of hatchery populations. Biological interaction between wild and hatchery populations should be an important consideration in the sustainable management of Pacific Salmon production based at the ecosystem level.The effects of climate events on the feeding ecology and trophic dynamics of Pacific salmon in offshore waters of the central Gulf of Alaska were investigated during early summers (1994-2000), based on analyses of stomach contents, and carbon and nitrogen stable isotopes. Gonatid squids (mainly Berryteuthis anonychus) were the dominant prey of all salmon species except for chum salmon. During 1997 El Nino event and the 1999 La Nina event, squids decreased sharply in the diets of all Pacific salmon except choho salmon in the Subarctic Current, and chum salmon diets changed from gelatinous zooplankton to a more diverse array of zooplankton species. Aδ13C and δ15N analysis indicated that all salmon species occupied the same branch of the food web in 1999-2000. We hypothesize that high-seas salmon adapt to climate-induced changes in their prey resources bye switching their diets either within or between trophic levels.The consequences of nutrient loss (oligotrophication) and attendant low productivity on biodiversity and productivity in the ecosystem have recently invoked the interest of researchers, as result of loss of wild anadromous fish (Pacific salmon) by acceleration of urbanization and deterioration of natural riparian ecosystem such dam construction, habitat destruction, and artificial hatchery program. In Japan, chum salmon have been mass-produced by hatchery program, while numerous wild Pacific salmon have been almost extinguished by a combination of the urbanization and the deterioration of riparian ecosystem. Anadromous fish are key species for sustaining production and biodiversity in the riparian ecosystem. For sustainable conservation management of riparian ecosystem, the rehabilitations of wild salmon population, system of material cycle, and natural rivers are critical important issued in Japan. Less