Seminar Details

When is bigger better? Some aspects of life history traits in fish using size-spectrum models




Dr. Karin Olsson - Tel Aviv University; and The Interuniversity Institute of Eilat


What affects the dynamics of life in the oceans? Marine ecosystems are highly complex and also under increasing pressure from anthropogenic exploitation, coastal usage and a changing climate. The need for developing a fundamental understanding, as well as a predictive capability, of marine ecosystems is therefore pressing. While traditional food-web models typically operate with a few species or functional groups, and may become overwhelmingly complex and data-demanding when extended to an entire ecosystem, the trait-based approach views the ecosystem on the level of individuals, which interact according to the traits they possess. According to this approach, the mechanism which determines the distribution of traits is the optimization of life strategies at the individual level. However, this approach requires a mechanistic understanding of the main functions of these traits, as well as of the associated trade-offs. In this talk, I will describe parts of the toolkit that the trait-based approach presents modelers with. I will then describe how these tools can be put to work to produce testable predictions of the life history of fish. In particular, I will focus on two aspects of the life histories of wild fish which are often poorly understood: reproduction and early life. Thus I will show how the trait-based approach can help the understanding of core principles underpinning the evolution of different life histories in fish, but also how it can be used to analyze the effect of assumptions in the absence of data, and how this can lead to contrary management advice and diverging predictions of resilience in fish populations.

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