Fisheries-induced evolution of metamorphosis
Approximately 80% of all animal species undergo a metamorphosis during their life cycle. Diet changes during ontogeny have been postulated as the first step in evolutionary history towards life cycles including metamorphosis. Such changes can lead to opposing selection pressures on a trait in different life-history stages, since different diets often require different morphologies to be effectively utilized. It is therefore thought that in species with an ontogenetic diet shift metamorphosis has evolved to allow for the independent evolution of stage-specific traits. However, metamorphosis is an energetically costly process that results in weight loss and higher predation rates. It is unclear when the potential benefits of metamorphosis can outweigh these disadvantages. The aim of the proposed project is to understand under which ecological conditions metamorphosis can evolve in species that change their diet over their life cycle.
Many fish species that are of commercial interest undergo metamorphosis in order to change habitat during their life. Harvesting of fish is typically size-selective, because larger individuals in a population are often the target of harvesting. High harvesting pressure on large individuals in a certain habitat changes the profitability of this habitat and therefore influences whether it is beneficial for individuals to switch to this habitat or not. I will therefore also study how size-selective harvesting affects the evolution of metamorphosis.