California Sea Grant College Program
Population Consequences of Age-Dependent Maternal Effects in Rockfish (Sebastes spp.)
- Author(s): Lucero, Yasmin
- et al.
I present a model of the early life history of a rockfish that includes an age-dependent maternal effect. The model is designed to accurately reflect the diverse uncertainties we have about early life history processes. The first portion of this thesis is devoted to an analytical treatment of the deterministic early life history model. I emphasize uncertainty about the functional form of density-dependent processes in the juvenile stage. The remainder of the thesis is devoted to demonstrating the properties of an agestructured population simulation with a productivity function that includes a maternal effect. I begin by examining a deterministic system, and then extend the analysis to a stochastic system. The simulation is used to calculate the time to recovery of an overfished rockfish population. I find that in the presence of an age-dependent maternal effect: (1) older populations are generally more productive than younger populations of the same biomass, (2) old fish provide a recovering population with buffering from environmental variability, (3) the size of the population impact of the effect depends significantly on the underlying life history pattern, and (4) managing an overfished population for age-structure has the largest positive impact when the rebuilding plan includes moderate harvest.