Humans are good at altering ecosystems, even unintentionally. Human actions can also alter selection pressures on organisms, driving new evolution. One example of such evolution that demands urgent attention is fisheries-induced evolution, in which harvest drives trait change in fish. The details of fisheries-induced evolution are fairly straightforward: larger, bolder fish are more likely to be caught by fishing gear, leaving smaller, shier individuals behind. The result is an evolved fishery, which may interact differently with its environment and have lower long-term stability.
|Harvest drives changes in fish behavior and morphology|
Growing evidence for trait change in harvested species has led to calls for fishery evolutionary impact assessments, which consider the effect of harvest-induced evolution on fishery yield, sustainability, and recovery. However, little work has considered the potential for evolution in lower, non-target trophic levels to impact fisheries.
Our recent modeling experiments reveal a harvest-driven eco-evolutionary trophic cascade: Declines in harvested species can drive cascading changes down food webs, altering selection pressures on lower trophic levels. Evolution in these lower trophic levels can cause cascading changes back up the food web, ultimately altering the abundance of the harvested species.
|Harvest-induced evolution in lower trophic levels predictably feeds-back to affect the harvested species.|
From Wood et al 2018, Scientific Reports. Used with a CC license.
|Advisor Mike Kinnison demonstrating his fishing skills.|
|Looking for eco-evolutionary trophic cascades with Eric Palkovacs' UCSC lab.|