NCEAS Product 11580

Botsford, Louis W.; Morgan, Lance; Lockwood, Dale; Wilen, James. 1999. Marine reserves and management of the northern California red sea urchin fishery. CalCOFI Reports. Vol: 40. Pages 87-93. (Abstract) (Online version)

Abstract

Catch in the northern California red sea urchin fishery has declined from 14,000 metric tons in 1988 to less than 1,000 in recent years. Although the institution of marine reserves is not expected to restore catch to former levels, reserves at least have the potential to prevent further decline. The answer to the question of whether reserves would benefit this fishery depends on an essential uncertainty in recruitment, which we model as a parameter in a Beverton-Holt relationship between number of larvae produced and successfully settling juveniles. For high values of the slope of this function at the origin, recruitment is relatively impervious to fishing, and the addition of reserves diminishes catch. For low values of this slope, fishing decreases recruitment, and the addition of reserves increases catch by increasing recruitment. A decision analysis accounting for the distribution of possible values of this slope indicates a benefit in long-term equilibrium catch of 18% with one-sixth of the coast in reserves. However, accounting for short-term losses due to the initial implementation of the reserves by considering only catches over the first 50 years reduces this gain to 12%. This figure is sensitive to the relative value of short-term and long-term gains, and to the rate at which reserves are implemented.