Marine Reserves

Collaborators:

• Alan Hastings - University of California, Davis
• Jim Wilen - University of California, Davis
• Dale Lockwood - University of California, Davis
• David Kaplan - University of California, Davis
• Steve Gaines - University of California, Santa Barbara
• Jim Quinn - University of California, Davis

Current Funding:

California Sea Grant

Focus:

Assessment of ecological function of marine reserves including the spatial configurations necessary to sustain populations in marine reserves, their sensitivity to uncertainty, and comparison of their performance to conventional fishery management.

An early result in this area was the use of a metapopulation model of the red sea urchin fishery to show that implementation of marine reserves could protect populations against collapse if the reserves were placed frequently enough along the coast (Fig.1) (Quinn, et al. 1994). A more general result was the demonstration that under certain assumptions, fishery management by marine reserves was the same as management by conventional means (Hastings and Botsford 1999). This result identified the close duality between conventional management and marine reserves, indicating that implementation of marine reserves had an effect similar to reducing fishing effort.

A second significant result was focussed sustainability of populations of any species in reserves rather than on the use of reserves in fishery management. We used a model of evenly spaced reserves with width w and spacing s, along with an exponentially decaying dispersal pattern to show that sustainable populations in reserves could be obtained either by single large reserves covering a low fraction of the coastline, or a system of smaller reserves that covered 35 percent of the coastline (Fig.2) (Botsford, et al. 2001). The former protected only species with dispersal distances up to the reserve width, while the latter protected species dispersing any distance. We recently showed that this result held for any dispersal pattern (Lockwood, et al. in press). This result points out that while marine reserves depend on uncertainty in the relationship between management policy and fishing mortality rate less than conventional management, they depend more on uncertainty in dispersal distance. Of the two possible spatial configurations of reserves, the system of reserves was shown to be the best for fishery management, basically because it provided more edges across which larvae could be transported from reserves to adjacent areas (Hastings and Botsford in press).

We have also recently reviewed the models analyses of marine reserves (Gerber, et al. in press) and synthesized a set of principles of marine reserve design (Botsford, et al., in press). In related work on the red sea urchin fishery, we have examined the effects of including fisher behavior in the analysis of marine reserves (Wilen, et al. in press) and we have examined the role of uncertainty in reserve management (see below re: red sea urchin).