A proactive GIS assessment of suitable offshore aquaculture sites in the Gulf of Maine integrating social, biological, and economic factors

Globally, the wild harvest of fish has reached a plateau, yet the demand for these species continues to grow (Tidwell and Allan 2001). Within the United States, there is an $8 billion seafood trade deficit, and 50% of the associated seafood imports are aquaculture-reared product (NOAA 2010). To lessen this gap, aquaculture production has been steadily growing, and will need to continue to do so. Because coastal zones are over-developed, over-capitalized, crowded, and in many cases beyond carrying capacity, increased growth in aquaculture must develop in new areas. Within the United States specifically, one area of interest for aquaculture development is the Gulf of Maine.

In anticipation of the challenge of offshore aquaculture and increasing demand for other uses in the ocean environmental that many view as already overcrowded, it is important to demonstrate that there is adequate space available for aquaculture in suitable areas.

This project has assessed available space for aquaculture development in the Gulf of Maine by concurrently assessing the distribution of marine mammals and sea turtles, and the current social and economic efforts of the fishing and shipping industries. This was done by identifying the spatial distribution of fishing effort (commercial and charter vessels) and the economic value (gross and net revenue) associated with this effort, the spatial distribution of commercial shipping and the economic costs of displacing current shipping lanes, and the spatial distribution of marine mammals and turtles. These data were combined to provide a cumulative use assessment, identifying the areas of high and low use of the data variables mentioned. The low use areas identified were then further assessed with other physical and geographic data to determine if they would be well suited for aquaculture.

One interesting result from this study was the discovery of a low use area in Nantucket Shoals. From this analysis we found this area could have the least amount of conflict and could be an appropriate area to integrate aquaculture, however, this may be an area of low used due to the existing Nantucket Lightship Closure area.

Nevertheless, with the advent of marine spatial planning, this study provides the structure on how to integrate very disparate data sources of use activities into a GIS proactive assessment. This technique can then be replicated with other data and integrated with other studies.

Spatial distribution of marine
mammals and turtles

Baleen whales and turtles
Cumulative use assessment
Identified low use areas
Low use areas
Shipping density
AIS density
Net revenue
Net revenue

For more information on this project, contact Michael Tlusty.

Tidwell, J H, and G L Allan. 2001. Fish as food: aquaculture's contribution. Ecological and economic impacts and contributions of fish farming and capture fisheries. EMBO reports 2, no. 11 (November):958-63. doi:10.1093/embo-reports/kve236.

NOAA 2010. U.S. Seafood Facts. Trade and Aquaculture.

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