The ecology of vulnerability in fishes

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Why are some species of animals more vulnerable to extinction than others? We are using marine and freshwater fish species as model systems to understand why some populations become extinct while others are highly resilient to human impacts. A two-part research program has been designed to answer these questions. First, large-scale comparisons will be made between a diverse array of fish species to understand how fundamental aspects of life cycles, such as age at maturity and rate of reproductive output, affect the ability of some fish species to be able to sustain fisheries, while others collapse. This will be combined with comparisons of population responses to habitat loss in freshwater fishes and terrestrial animals, to improve the way in which we prioritize species for conservation. The second part of the reserch program will use Pacific salmon as a model system for understanding how key populations that are important to fisheries affect other species. Field studies in a remote coastal region of British Columbia will test for the importance of nutrients derived from salmon after the fish have spawned and died. Natural variation among salmon streams in salmon densities will be related to uptake of salmon-derived nutrients in plants, insects and vertebrates along streams and forests. A complementary large-sclae experiment will involve additions of carcasses to parts of streams, in order to study the short- and long-term impacts on various aspects of biodiversity. This information will be used to help inform more holistic management that includes not only salmon, but also takes account of indirect impacts on the wider environment.