Changing trophic structure and energy dynamics in the Northwest Atlantic: implications for Atlantic salmon feeding at West Greenland
Changing trophic structure and energy dynamics in the Northwest Atlantic: implications for Atlantic salmon feeding at West Greenland
复制标题
西北大西洋营养结构和能量动态的变化：对西格陵兰岛大西洋鲑鱼摄食的影响
DOI：
10.3354/meps11470
复制
发表时间：
2015
影响因子：
2.5
通讯作者：
R. Nygaard
中科院分区：
文献类型：
--
作者：
Mark D. Renkawitz;T. Sheehan;H. Dixon;R. Nygaard
西北大西洋大规模气候条件的变化导致了生产力的阶段性转变，改变了影响许多物种生长，生存和丰度的营养途径。尽管种群结构和管理制度各不相同，但北美和欧洲不同大西洋鲑鱼种群的丰度同时下降，这表明常见海洋区域经历的条件可能是原因。为了了解导致种群下降的营养机制，收集了1451条大西洋鲑鱼胃，并从2006年至2011年在西格陵兰觅食地捕获的个体中进行了检查。标准化的胃内容物重量和胃组成不同的年份，但没有股票复杂。大西洋鲑鱼消耗各种猎物类群，主要是毛鳞鱼和Themisto sp.，在宽的尺寸范围内。标准化的胃内容物重量和比例的类群消费之间的历史（1965 - 1970年）和当代的样品是相似的，虽然低质量的boreoatlantic臂钩鱿鱼，几乎没有从历史数据，是中等的重要性，在当代的样品，而高质量的毛鳞鱼的重要性下降。此外，从1968年至2008年，毛鳞鱼的平均能量密度估计值，该地区的关键饲料物种，下降了约33.7%。这导致随着时间的推移，对大西洋鲑鱼总能量消耗的估计较低。结果表明，40年来不断变化的海洋条件所造成的营养动态变化产生负面影响大西洋鲑鱼和可能的许多其他商业，文化和生态上重要的物种在西北大西洋。确定影响海洋食物网的主要机制是必要的，以充分了解和评估生存和生产力的趋势，并建立切实可行的管理目标的商业，娱乐和受保护的物种。
Changes in large-scale climate conditions in the Northwest Atlantic caused a phase shift in productivity, altering trophic pathways that influence the growth, survival, and abundance of many species. Despite diverse population structures and management regimes, concurrent abundance declines in disparate North American and European Atlantic salmon populations suggest that conditions experienced at common marine areas may be causative. To understand the trophic mechanisms contributing to population declines, 1451 Atlantic salmon stomachs were collected and examined from individuals caught between 2006 and 2011 at the West Greenland feeding grounds. Standardized stomach content weights and stomach composition varied among years but not between stock complexes. Atlantic salmon consumed a variety of prey taxa, primarily capelin and Themisto sp., over a broad size spectrum. Standardized stomach content weight and proportions of taxa consumed were similar between historical (1965−1970) and contemporary samples, although lower-quality boreoatlantic armhook squid, nearly absent from historical data, was of moderate importance in contemporary samples, while higher-quality capelin decreased in importance. Furthermore, from 1968−2008 mean energy density estimates of capelin, the regional keystone forage species, decreased approximately 33.7%. This resulted in lower estimates of total energy consumption by Atlantic salmon over time. Results indicate that altered trophic dynamics caused by 40 yr of changing ocean conditions negatively influenced Atlantic salmon and likely many other commercially, culturally, and ecologically important species in the Northwest Atlantic. Determining the primary mechanisms that influence marine food-webs is necessary to fully understand and evaluate survival and productivity trends and to establish realistic management targets for commercial, recreational, and protected species.