Allelic inflation in depleted fish populations with low recruitment

Abstract

AbstractWhen the recruitment process in highly fecund species involves within-litter correlations in survival probability, the offspring-number distribution can exhibit a power law. Such reproductive skew appears to be prevalent in abundant marine species. We show that an apparent paradox arises in the reproductive skew model. In years of occasionally large recruitment, we expect to observe elevated levels of relatedness among recruits. Conversely, the effective number of alleles within the population is inflated during periods of low-recruitment. Thus, depressed fish populations have excesses of singleton offspring and thus, overexploitation may cause stock depletion but with increasing genetic diversity. Some studies have documented such a diversity paradox. It does not seem possible to explain large effective population sizes of collapsed species on the basis of normal reproduction models in the domain of attraction of the Kingman coalescent. The approach outlined here provides a novel method to examine the resilience and potential for recovery in depleted populations using short-length time-series data on recruitment.