School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA 98195, USA.
Biol Lett. 2013 Feb 23;9(1):20120824. doi: 10.1098/rsbl.2012.0824.
We used carbon and nitrogen stable isotopes from muscle tissues accrued in the ocean to examine whether marine foraging tactics in anadromous sockeye salmon (Oncorhynchus nerka) are linked to their ultimate freshwater life history as adults. Adults from large-bodied populations spawning in deep freshwater habitats had more enriched δ(15)N than individuals from small-bodied populations from shallow streams. Within populations, earlier maturing individuals had higher δ(15)N than older fish. These differences in δ(15)N suggest that the fish with different life histories or spawning habitats in freshwater either fed at different trophic positions or in different habitats in the ocean. We propose that, nested within interspecific diversity in the ecological attributes of salmon, population and life-history diversity in spawning adults is associated with variation in marine foraging tactics. These results further indicate that the trophic diversity of sockeye salmon in the ocean may be linked to trade-offs in ecological and evolutionary constraints they eventually experience as adults in freshwater ecosystems.
我们利用海洋肌肉组织中积累的碳和氮稳定同位素，来研究溯河洄游的红大麻哈鱼（Oncorhynchus nerka）的海洋觅食策略是否与其作为成鱼的最终淡水生活史有关。在深淡水栖息地产卵的大型个体的δ(15)N 比来自浅溪流的小型个体更为丰富。在种群内部，成熟较早的个体的δ(15)N 比年龄较大的个体更高。这些δ(15)N 的差异表明，具有不同生活史或淡水产卵栖息地的鱼类，要么在海洋中处于不同的营养层次，要么在不同的栖息地觅食。我们提出，在鲑鱼生态属性的种间多样性中，产卵成鱼的种群和生活史多样性与海洋觅食策略的变化有关。这些结果进一步表明，海洋中红大麻哈鱼的营养多样性可能与其在淡水生态系统中成鱼时所经历的生态和进化限制的权衡有关。
