Case Study for Week 2

My case study for this week centered on reducing bycatch of juvenile red snappers by shrimp trawls in the Gulf of Mexico. The paper is: Designing marine reserves to reduce bycatch of mobile species: a case study using juvenile red snapper (Lutjanus campechanus), by Diamond et al.

 

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Red snapper from the Gulf of Mexico

 

The research team made use of geographic information system (GIS) to map fishery-independent trawl surveys done by the Southeast Area Monitoring and Assessment Program (SEAMAP) every summer and fall in the Gulf of Mexico from 1987 to 1997.

The paper attempts to asses whether there is a geographic pattern to the distribution of juvenile red snappers.

Diamond et al. analyzed juvenile red snapper distribution and examined “hot spots” with high concentration (intensity) and the predictability for the hotspot to reoccur in the same position over time (persistence). In designing marine reserves, one could designate no-trawling zones according to the desired level of intensity and persistence which correspond to percent or numerical bycatch-reduction goals.

In further consideration, given that red snappers are highly mobile and higher-intensity hotspots are often unpredictable, a no-trawling zone does not need to be permanent. Ideally, such a no-trawling zone could be fluid from year to year, in order to avoid trawling in higher-intensity hotspots.

For a no-trawling zone to be fluid, it would depend on how effectively this information could be disseminated in a timely manner. This could also apply to marine vessel no-go zones in the activity range of Southern Resident Killer whales. In the San Juan community, dissemination of information should be relatively easy due to wide availability of communication technology.

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