Ecotrust in the News
MPA News
October 2007
How software can help design MPAs with lesser impact on fishermen
The use of software tools is increasing in the field of MPA design due to their ability to perform complex tasks. By incorporating an abundance of data on species, habitats, and other biodiversity features, programs like MARXAN can help identify networks of sites to meet biodiversity targets while minimizing potential negative impacts on resource users ("Using Computer Software to Design Marine Reserve Networks", MPA News 6:4).
The ability of MARXAN to help lessen the costs of new no-take areas to fishermen was presented by Carissa Klein of the University of Queensland (Australia). Klein analyzed a new network of no-take areas along the central coast of the US state of California, designated in 2007 as part of implementing the state's Marine Life Protection Act. Using MARXAN, she designed an alternative network of no-take areas that achieved the same level of habitat representation as designs for the new network, but at 20%–50% less cost to fishermen (both commercial and recreational).
Klein measured the cost to fishermen in "total fishing effort lost" across 19 fisheries: i.e., the amount of fishing effort that would be lost if an area were closed to all types of fishing. She assumed that lost fishing effort would not be redistributed to other, unprotected areas in the region. (She acknowledges that in reality some of the "lost effort" would be displaced to other areas.) In a parallel analysis, Klein also designed an alternative network that assumed the same level of impact on fisheries as the California network, but was able to incorporate as much as 9.5% more of each habitat in her closed areas.
Key to Klein's research was the inclusion of spatially explicit, fine-scale data from fishermen in her models — namely, the spatial distribution of their fishing effort. She says California's process of designing the actual network was not privy to the same amount of socioeconomic data because it revealed confidential information on individual fishing grounds. Without comprehensive data on current fishing effort, planning processes have more difficulty gauging the expected impact of various network designs on stakeholders.
Despite the effectiveness of MARXAN in designing optimal reserve networks, Klein says the software should not take the place of stakeholder-driven planning processes. "Stakeholders play an important role in designing marine reserves," she says. "For example, they are needed to define biodiversity conservation and socioeconomic objectives, address any objectives that are not incorporated in the software, and support the final outcome. If the planning objectives are clear, MARXAN can support stakeholders in designing marine reserves that represent biodiversity features for a minimal cost." Klein conducted this research in collaboration with Charles Steinback and Astrid Scholz (both of Ecotrust, an NGO) and Hugh Possingham of the University of Queensland.
