Reducing Fisheries' By-Catch Through Mathematical Analysis

One possible solution, advanced by NSERC grantee Dr. Suzana Dragicevic of Simon Fraser University (SFU) in British Columbia involves digital maps and mathematical analysis to visualize and better understand the location of the most vulnerable marine habitats. These so-called 'geospatial' approaches have already been used widely in managing land-based resources to help build consensus among stakeholders with conflicting interests.

"Many environmental problems, including by-catch, are spatial in nature, explains Dragicevic, associate professor and director of the Spatial Analysis and Modeling Laboratory in SFU's Geography Department. "To resolve them you need to build an accurate and objective view of the environment in question."

What makes the challenge daunting is the conflict between commercial fisheries driven by profit maximization and an increasingly determined conservation community intent on protecting as much as 30 per cent of the world's marine habitats. "We must certainly be mindful of the need to protect marine biodiversity, but we can't forget those who are dependent on the fishery for their livelihoods," says Dragicevic, who is also funded by the Social Sciences and Humanities Research Council of Canada.

To find common ground, Dragicevic employs a mathematical optimization process known as multi-criteria evaluation. This tool factors in the competing preferences of stakeholders to help authorities arrive at management decisions acceptable to all parties.

"Multi-criteria analysis has long been successful in resolving conflicts over terrestrial resource management such as land-use suitability analysis and urban development. Recently, we have shown how the approach can be applied to marine environments."

Dragicevic, in collaboration with Louisa Wood, a doctoral researcher at the University of British Columbia's Fisheries Centre, tested their approach under a pilot project in the Pacific Canadian Exclusive Economic Zone (EEZ). The results, published in the Biodiversity and Conservation Journal, confirmed that the methodology can help decision-makers wrestle with the complex trade-offs between fishing and biodiversity conservation.

These methods were presented February 15 during a seminar at the 2008 meeting of the American Association for the Advancement of Science in Boston.