Do We Have to Choose? Balancing Conservation and Harvest Goals in Rebuilding a Stock

Public pressure to rebuild collapsed fish stocks, even in the face of rising food demands, necessitates a fresh look at the tradeoffs between conservation and fishing. We examined the question “Is harvest compatible with stock rebuilding?” in relation to the proposed red abalone (Haliotis rufescens) fishery in the Channel Islands. Abalone stocks have suffered declines worldwide, and appear to be particularly vulnerable to overfishing. The red abalone fishery was closed in 1997 after years of unsustainable catches led to a spatial contraction in the fishery. Since the closure there has been evidence of population recovery at San Miguel Island, an area that never experienced severe declines in landings. Using data recently collected during three years of collaborative surveys at San Miguel Island we constructed a spatially explicit age-structured bio-economic model that incorporates stochastic recruitment and dispersal dynamics. We identified optimal management strategies in relation to a multi-criteria objective function that weights both economic (fishery) and conservation (stock rebuilding) interests. We outline how the allocation of varying harvest efforts over time and space affects both the net present value of the stock and population growth, and present the efficiency frontiers for the management strategies examined. Our results demonstrate that joint economic-conservation benefits increase with increasing complexity in management (employing multiple strategies in concert). While this level of strategic management may be impractical in an open access fishery, it could be achieved through a cooperative management structure such as the one currently proposed for an experimental red abalone fishery at San Miguel Island.