Washington State University, Puyallup Research and Extension Center, 2606 W. Pioneer Ave., Puyallup, WA 98371, USA.
National Research Council, under contract to Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. E., Seattle, WA 98112, USA.
Environ Pollut. 2018 Jul;238:196-203. doi: 10.1016/j.envpol.2018.03.012. Epub 2018 Mar 20.
Adult coho salmon (Oncorhynchus kisutch) prematurely die when they return from the ocean to spawn in urban watersheds throughout northwestern North America. The available evidence suggests the annual mortality events are caused by toxic stormwater runoff. The underlying pathophysiology of the urban spawner mortality syndrome is not known, and it is unclear whether closely related species of Pacific salmon are similarly at risk. The present study co-exposed adult coho and chum (O. keta) salmon to runoff from a high traffic volume urban arterial roadway. The spawners were monitored for the familiar symptoms of the mortality syndrome, including surface swimming, loss of orientation, and loss of equilibrium. Moreover, the hematology of both species was profiled by measuring arterial pH, blood gases, lactate, plasma electrolytes, hematocrit, and glucose. Adult coho developed behavioral symptoms within a few hours of exposure to stormwater. Various measured hematological parameters were significantly altered compared to coho controls, indicating a blood acidosis and ionoregulatory disturbance. By contrast, runoff-exposed chum spawners showed essentially no indications of the mortality syndrome, and measured blood hematological parameters were similar to unexposed chum controls. We conclude that contaminant(s) in urban runoff are the likely cause of the disruption of ion balance and pH in coho but not chum salmon. Among the thousands of chemicals in stormwater, future forensic analyses should focus on the gill or cardiovascular system of coho salmon. Because of their distinctive sensitivity to urban runoff, adult coho remain an important vertebrate indicator species for degraded water quality in freshwater habitats under pressure from human population growth and urbanization.
成年银鲑（Oncorhynchus kisutch）在从海洋洄游到北美西北部城市流域产卵时会过早死亡。现有证据表明，每年的死亡事件是由有毒的雨水径流造成的。城市产卵者死亡综合征的潜在病理生理学尚不清楚，也不清楚是否密切相关的太平洋鲑鱼也面临类似的风险。本研究将成年银鲑和红大麻哈鱼（O. keta）暴露于高交通量城市动脉道路的径流中。监测产卵者是否出现死亡综合征的典型症状，包括水面游泳、定向丧失和失去平衡。此外，通过测量动脉 pH 值、血气、乳酸盐、血浆电解质、红细胞压积和葡萄糖来分析两种鱼类的血液学特征。暴露于雨水径流中的成年银鲑在几小时内就出现了行为症状。与银鲑对照相比，各种测量的血液学参数都有显著变化，表明血液酸中毒和离子调节紊乱。相比之下，暴露于径流中的红大麻哈鱼产卵者基本上没有表现出死亡综合征的迹象，测量的血液血液学参数与未暴露的红大麻哈鱼对照相似。我们得出结论，城市径流中的污染物可能是导致银鲑而非红大麻哈鱼离子平衡和 pH 紊乱的原因。在雨水径流中的数千种化学物质中，未来的法医分析应集中在银鲑的鳃或心血管系统上。由于它们对城市径流的独特敏感性，成年银鲑仍然是淡水生境中因人口增长和城市化而受到压力的退化水质的重要脊椎动物指示物种。
