Institute for the Oceans and Fisheries, University of British Columbia, AERL, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
Pacific Science Enterprise Center, Fisheries and Oceans Canada, West Vancouver, BC, V7V 1N6, Canada.
Sci Rep. 2020 May 22;10(1):8517. doi: 10.1038/s41598-020-65557-1.
Fish growth and survival are largely determined by the nutritional quality of their food, and the fish that grow quickly during early life stages are more likely to reproduce. To adequately estimate the quality of the prey for fish, it is necessary to understand the trophic links at the base of the food-web. Trophic biomarkers (e.g., stable isotopes and fatty acids) are particularly useful to discriminate and quantify food-web relationships. We explored the connections between plankton food-web components, and the seasonal and spatial dynamics of the trophic biomarkers and how this determines the availability of high-quality prey for juvenile Pacific salmon and Pacific herring in the Strait of Georgia, Canada. We demonstrate that the plankton food-web in the region is largely supported by diatom and flagellate production. We also show that spatial differences in terms of energy transfer efficiency exist in the region. Further, we found that the fatty acid composition of the zooplankton varied seasonally, matching a shift from diatom dominated production in the spring to flagellate dominated production in the summer. This seasonal shift conferred a higher nutritional value to zooplankton in the summer, indicating better quality prey for juvenile salmon and herring during this period.
鱼类的生长和存活在很大程度上取决于其食物的营养质量，而在生命早期快速生长的鱼类更有可能繁殖。为了充分评估鱼类猎物的质量，有必要了解食物网底层的营养联系。营养生物标志物（例如，稳定同位素和脂肪酸）特别有助于区分和量化食物网关系。我们探讨了浮游生物食物网成分之间的联系，以及营养生物标志物的季节性和空间动态，以及这如何决定加拿大乔治亚海峡幼鲑鱼和太平洋鲱鱼的高质量猎物的可利用性。我们证明，该地区的浮游生物食物网主要由硅藻和鞭毛藻的生产支持。我们还表明，该地区存在能量传递效率方面的空间差异。此外，我们发现浮游动物的脂肪酸组成具有季节性变化，与春季以硅藻为主的生产向夏季以鞭毛藻为主的生产转变相匹配。这种季节性转变使夏季浮游动物具有更高的营养价值，表明在此期间幼鲑鱼和鲱鱼的猎物质量更好。
