OFFSHORE SHELLFISH AQUACULTURE IN THE EEZ: THE POTENTIAL FOR THE FARMING INDUSTRY EXEMPLIFIED BY EFFORTS IN THE NORTHEAST U.S.

The United States  plans to increase domestic seafood production and decrease dependency on imports. Accelerating  interest in expanding shellfish aquaculture to offshore areas  prompted  the need for research on the feasibility of farming in the open ocean along all coasts . Technological, environmental, and legal  challenges engendered skepticism within the scientific community, stakeholders, and managers. As success  of a shellfish farm is ultimately determined by the consistency of productive yields of high quality seafood , suitability of the environment should be an essential consideration when expanding aquaculture offshore . The offshore culture of the local candidate species Blue mussel, Mytilus edulis , employs submerged longlines, thus depth suitability is paramount for successful farm production.

Within a candidate study area off the coast of the Northeast U.S., an area with a venerable fisheries history, suitable depth thresholds were defined using open-source databases  of two main environmental  variables:  temperature and food availability, expressed as chlorophyll a. These environmental variables were used in conjunction with species ecological knowledge to assess habitat suitability for blue mussel a quaculture in three dimensions.  To validate the analysis, in addition to the determination of depth thresholds for northern and southern areas of New England, we performed in situ measurements of mussel feeding performance  using a biodeposition method at an experimental offshore farm in Massachusetts.

Measurements showed that the local seston was of high quality, and environmental characteristics were ecologically suitable at predicted depths. Mussel performance was satisfactory, even though feeding rates were lower than in coastal areas, confirming the experimental farm as a good candidate site for offshore mussel farming. Although results are local, this study contributes to management decisions and further asserts that blue mussel farming is suitable in offshore habitats. It also serves as a positive example for other countries interested in evaluating opportunities for marine farming in offshore EEZ areas.