Shuttle System for Evaluating Effects of Environmental Stressors on Fish Behaviour

点击翻译按钮获取中文摘要

Hypoxia (low dissolved oxygen, DO) is one of the most serious manifestations of human-induced stress to inland and coastal waters driven by influxes of wastes and fertilizer runoffs that accelerate eutrophication and pollution. Climate change may exacerbate hypoxia, because oxygen solubility decreases with rising temperature while the metabolism of ectotherms (cold-blooded organisms) like fish increases. Fishes employ many and diverse strategies to avoid problems associated with hypoxia. Some responses are activated quickly (e.g., minutes, days), whereas others are developmentally plastic and/or genetically fixed. Initial (fast) responses to hypoxic stress are often behavioural (e.g., avoidance behaviour) and may occur at DO levels far higher than lethal levels. These behavioural responses can alter crucial relationships between a fish and its environment (e.g., predator-prey interactions). Given the increasing incidence of hypoxia worldwide, it is critical that we learn to predict the levels at which low DO leads to behavioural changes and ecological effects. A very useful route to addressing these issues is the use of "choice" or "preference" tests to determine ecologically relevant thresholds. The Shuttle Box, an automated 2-compartment preference/avoidance test system designed by Loligo Systems, is unique in that it allows rigorous estimates of DO and thermal preference/avoidance behaviour and critical thresholds at which behavioural changes are induced by thermal and hypoxic stress. Using this system we propose to (1) quantify DO/temperature preference; (2) quantify how hypoxia and thermal stress modify behavioural interactions, and (3) how the responses to 1-2 are altered by the interaction of hypoxia and thermal stress. This equipment will facilitate collaboration and training both nationally and internationally, and results will have direct application to predicting response to hypoxia, a global environmental stressor, and its interaction with climate warming, another pervasive stressor. We estimate that each year this system will be used by at least 1 PDF, 2-3 graduate students, 3 undergraduates, and a research assistant, thus contributing to the training of 7-8 HQP per year.