School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Seattle, Washington 98105, USA.
Ecol Appl. 2012 Jul;22(5):1460-71. doi: 10.1890/11-2001.1.
Copper contamination in surface waters is common in watersheds with mining activities or agricultural, industrial, commercial, and residential human land uses. This widespread pollutant is neurotoxic to the chemosensory systems of fish and other aquatic species. Among Pacific salmonids (Oncorhynchus spp.), copper-induced olfactory impairment has previously been shown to disrupt behaviors reliant on a functioning sense of smell. For juvenile coho salmon (O. kisutch), this includes predator avoidance behaviors triggered by a chemical alarm cue (conspecific skin extract). However, the survival consequences of this sublethal neurobehavioral toxicity have not been explored. In the present study juvenile coho were exposed to low levels of dissolved copper (5-20 microg/L for 3 h) and then presented with cues signaling the proximity of a predator. Unexposed coho showed a sharp reduction in swimming activity in response to both conspecific skin extract and the upstream presence of a cutthroat trout predator (O. clarki clarki) previously fed juvenile coho. This alarm response was absent in prey fish that were exposed to copper. Moreover, cutthroat trout were more effective predators on copper-exposed coho during predation trials, as measured by attack latency, survival time, and capture success rate. The shift in predator-prey dynamics was similar when predators and prey were co-exposed to copper. Overall, we show that copper-exposed coho are unresponsive to their chemosensory environment, unprepared to evade nearby predators, and significantly less likely to survive an attack sequence. Our findings contribute to a growing understanding of how common environmental contaminants alter the chemical ecology of aquatic communities.
水域中铜的污染在采矿活动或农业、工业、商业和住宅人类土地利用的流域中很常见。这种广泛存在的污染物对鱼类和其他水生物种的化学感觉系统具有神经毒性。在太平洋鲑鱼（Oncorhynchus spp.）中，以前已经表明，铜引起的嗅觉损伤会破坏依赖嗅觉正常运作的行为。对于幼年银鲑（O. kisutch），这包括由化学警报线索（同种鱼皮肤提取物）触发的捕食者回避行为。然而，这种亚致死神经行为毒性的生存后果尚未得到探索。在本研究中，幼年银鲑暴露于低水平的溶解铜（5-20 微克/升，持续 3 小时），然后暴露于表明捕食者接近的线索。未暴露的银鲑对同种鱼皮肤提取物和上游存在的已喂食幼年银鲑的大口黑鲈捕食者（O. clarki clarki）的反应表现出游泳活动急剧减少。暴露于铜的猎物鱼没有这种警报反应。此外，在捕食试验中，与未暴露于铜的银鲑相比，铜暴露的银鲑更容易受到大口黑鲈的攻击，其攻击潜伏期、存活时间和捕获成功率都有所提高。当捕食者和猎物共同暴露于铜时，捕食者-猎物动态的转变相似。总的来说，我们表明，暴露于铜的银鲑对其化学感觉环境没有反应，没有准备好逃避附近的捕食者，并且在攻击序列中存活的可能性明显降低。我们的研究结果有助于更好地理解常见环境污染物如何改变水生群落的化学生态学。
