The appropriate configuration of marine reserves for maximizing harvests or ensuring species persistence when there is uncertainty or variability in larval dispersal patterns is not completely understood. This is particularly true in environments with large alongshore advection rates, as the success of a system of marine reserves depends on connectivity through larval and/or adult dispersal between adjacent marine reserves. In this paper, the consequences of alongshore advection in the presence of marine reserves for a fish species with sedentary adults and widely dispersing larvae are examined. First, a uniform configuration of reserves with constant alongshore advection rate is considered. The highest overall catch and recruitment rates occur when the spacing between reserves is precisely tuned to the advection distance. When the alongshore advection distance is allowed to vary in time, catch and recruitment are considerably less sensitive to alongshore advection. At small diffusion distances, catch values differ from what would be predicted from the time-averaged larval dispersal pattern due to density-dependent post-settlement effects. It is important to include short time scale settlement variability in marine reserve models under these conditions. When the spacing between reserves is allowed to vary, the tuning of the system to particular advection distances is less precise. Configurations of marine reserves with a variety of spacings between reserves exhibited more uniform catch levels as a function of advection distance. This suggests that variability in the spacing between reserves is desirable for protecting a diverse group of species with different dispersal patterns.

The size and configuration of marine reserves best suited to reaching fisheries and conservation goals are poorly understood. It has been suggested that variable spacing between reserves is essential to the success of a system of marine reserves. We used numerical models to examine the effect of variable spacing on the efficacy of marine reserves for managing a fish species with sedentary adults and planktonic larvae. Variability in reserve spacing affected catch and recruitment relative to values for a uniform configuration of reserves only for populations near collapse even in the presence of a system of reserves. For species with low fishing rates or large marine reserves, variability in spacing had only a minor effect. At high fishing rates and small reserve sizes, variable reserve placement had a positive local effect on catch and recruitment when several reserves fell close to each other. These configurations led to uneven spatial distributions with greater catch and recruitment in areas with a higher concentration of reserves. Variable reserve spacing can offer additional protection to overfished populations along certain sections of the coastline, but concern for spatial homogeneity will argue for a uniform distribution of reserves covering an adequate proportion of the entire coastline.