Fundamental population–productivity relationships can be modified through density-dependent feedbacks of life-history evolution

Abstract

The evolution of life histories over contemporary time scales will almost certainly affect population demography. One important pathway for such eco-evolutionary interactions is the density-dependent regulation of population dynamics. Here, we investigate how fisheries-induced evolution (FIE) might alter density-dependent population–productivity relationships. To this end, we simulate the eco-evolutionary dynamics of an Atlantic cod ( Gadus morhua) population under fishing, followed by a period of recovery in the absence of fishing. FIE is associated with increases in juvenile production, the ratio of juveniles to mature population biomass, and the ratio of the mature population biomass relative to the total population biomass. In contrast, net reproductive rate ( R ₀ ) and per capita population growth rate ( r) decline concomitantly with evolution. Our findings suggest that FIE can substantially modify the fundamental population–productivity relationships that underlie density-dependent population regulation and that form the primary population-dynamical basis for fisheries stock-assessment projections. From a conservation and fisheries-rebuilding perspective, we find that FIE reduces R ₀ and r, the two fundamental correlates of population recovery ability and inversely extinction probability.