Harvesting and its impacts on phenotypes in the targeted populations have been of interest particularly in fisheries context, but most of the studies in this field have explored shifts in mean traits values. Earlier, I have blogged about a study by Olsen et al. (2009) challenging this view by demonstrating how fishing might have decreased phenotypic variance in cod without impacts on mean, but now opposite results in this respect have been found. The recent study on Windermere (UK) pike population illustrates how intensive fishing mortality at intermediate sizes might actually have increased phenotypic variability in the populations. In the light of the theory of life-history evolution this may not be surprising, but viewed from practical fisheries management’s perspective the outcome is interesting. Is selection increasing phenotypic variability actually favorable? In theory, phenotypic variability helps a population to survive in a changing environment, but if variance increases because of population being more clearly split into two alternative life-history strategies, how might that affect population’s current and future viability? I guess that “warrants for future research”…
Edeline et al. (2009) Harvesting-induced disruptive selection increases variance in fitness related traits. Proc R Soc B (in press)
