for a 1-dimensional ocean with a mean current from left to right as a function of the alongshore distance and the mean larval transport distance, L
. The heavy black line represents the width of the retention zone Lreten = L2diff/Ladv from the upstream edge of the domain. (B) Nallele normalized by the critical value of Nallele needed to allow retention, as given by eq. (1). (C) The logarithm of average persistence time of a novel allele in generations as a function of the location where the allele first appeared. (D) The population density per length of the domain, normalized by the carrying capacity. The stochastic component of larval transport, Ldiff, is 100 km, the carrying capacity of the domain is 1 individual/km, and the domain is 2048 km in size.