Graduation date: 2005
Overfishing of our national marine resources has degraded some of the most
productive fishing regions in the Northwest Atlantic Ocean, most notably the Gulf of Maine
and Georges Bank. These regions may have shifted from productive trophic regimes to a less
than optimal state therefore reducing fishers’ catches and associated revenue from
commercially targeted species (Sinclair and Murawski, 1997, Jennings et al, 2001). Marine
protected areas (MPAs) have been offered as an effective management tool to preserve
biodiversity, enhance commercial fisheries, and protect against poor decisions in fisheries
management (Bohnsack, 1999). Geographic information systems (GIS) bring together the
fields of geography and fisheries management to help build a better understanding of the
spatial interactions of complex marine environments (e.g., Kracker, 1999). Using GIS and
spatial management such as MPAs can help fishery managers conserve and improve the
population status of important biological resources while helping to preserve commercial
fishing, an important social and political industry in New England.
Incorporating the needs of stakeholders in management decisions is necessary in order
to implement an effective fisheries management strategy (e.g., Malakoff, 2002). This study
used a weighted optimization raster model in a GIS to compare biological significant regions,
which were composed of biodiversity estimates and spawning and juvenile habitats, to
important commercial fishing grounds in the Gulf of Maine and Georges Bank. Biodiversity,
spawning and juvenile data values were derived from fishery independent data collected by
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the National Marine Fisheries Service in Woods Hole, MA. The essential commercial fishing
zones were created from Vessel Trip Reports, which are derived directly from reports sent in
by federally permitted fishers. The weighted model compares the biologically important
resources from an area, or cell, to the level of commercial fishing occurring in the same cell
using simple mathematically algorithms in map algebra. The model output shows where
placement of MPAs might be most beneficial in order to conserve marine resources and
enhance fisheries, as well as areas where fishing is more suitable. Output can be viewed in
multiple ways, a spectrum of values ranging from negative numbers to positive ones or simply
as areas important for the fishing community or potential MPA. The more negative the value
in the spectrum output then the more important the area would be for fishers and conversely
the more positive the output then the more suitable the area would be for possible MPA
designation.
The optimization model can be tuned to meet management goals and objectives by
adjusting the weighting scenarios for the input variables. The model design can be used for
multiple species and ecosystem management or to protect specifically targeted species of
particular concern. Managers may use the output to delineate MPAs in a variety of ways
depending on the conditions of the resources and the prospects of the fishing community.
Managers will enjoy greater success as the needs of both fishers and biological resources are
met.