The first environmental suitability study for blue mussel culture in federal waters off New England’s shore was conducted by scientists from the Northeast Fisheries Science Center’s Milford Laboratory. The study revealed great potential for farming. The scientific team has continued this work, furthering the case for offshore mussel farms in a recent perspectives column in Fisheries Magazine. They have also published findings in Ocean & Coastal Management, examining the risks harmful algal blooms pose to offshore aquaculture.
The Case for Mussels
Milford’s Darien Mizuta and Gary Wikfors suggest that a New England offshore mussel farming industry would be environmentally sustainable and beneficial for food security and the economy. The United States is the world’s top importer of seafood, despite having the second largest Exclusive Economic Zone. In May, the president of the United States signed an executive order promoting American seafood competitiveness and economic growth. The order calls for increasing domestic seafood production, including making aquaculture permitting more efficient and predictable and bolstering aquaculture research.
Mussels are the top imported bivalve shellfish in the United States, currently contributing more than $102 million to the $14 billion U.S. seafood deficit. Close to Canada’s mussel-producing Prince Edward Island, New England is the import epicenter for mussel products, including fresh live mussels, frozen mussels, and prepared mussel dinners.
With advances in mussel farming in the 1990s, the United States began importing more mussels, mostly from Canada. “The success of Prince Edward Island mussel farming has created a new market for mussels in the northeast United States that is growing beyond the production capacity of PEI,” explains Wikfors, who is also the director of the Milford Laboratory, where Darien Mizuta was a postdoctoral researcher.
In their column, Mizuta and Wikfors point out that U.S. mussel production has not kept pace with increasing demand. Despite favorable environmental conditions for farming over large expanses of the Northeast’s offshore waters, including ocean temperatures and food availability, there are no offshore commercial mussel farms in the region. Mussels feed on natural algae and don’t require added food, meaning they could be a sustainable crop that makes a dent in the seafood trade deficit.
Offshore mussel production in the Northeast is not limited by technical know-how. Mizuta and Wikfors describe two decades of research and government investment in experimental offshore aquaculture. This includes the Salem State University experimental farm off Cape Ann, Massachusetts, which is collecting data for management agencies. Despite encouraging results, these efforts have not yet yielded a product sold on the national market.
Wikfors and Mizuta describe regulatory uncertainty as the most significant barrier hindering the otherwise promising prospect of offshore mussel aquaculture. They make the case for a clear, streamlined regulatory framework that protects vulnerable species while also accommodating offshore farming. Offshore farming, compared with coastal aquaculture, has the advantages of fewer conflicts with other ocean users and less concern about exposure to coastal pollution.
"Developing a local offshore industry for this aquaculture species is important, in terms of local economic benefits and food security, and producing seafood according to national standards of quality and sustainability."
Wikfors and Mizuta highlight the imperative to develop a domestic industry. “Developing a local offshore industry for this aquaculture species is important, in terms of local economic benefits and food security, and producing seafood according to national standards of quality and sustainability,” says Mizuta.
The local food movement further fuels this opportunity. In a recent NOAA-funded survey conducted by the Atlantic Corporation, residents of the northeastern United States indicated that they would be willing to pay more for fresh and local seafood.
Harmful Algal Blooms and Offshore Farming
In addition to regulatory uncertainty, Mizuta and Wikfors investigated another barrier to offshore farming—lack of offshore monitoring of harmful algal blooms (HABs) on the Eastern Seaboard. Their work suggests that mussel farms could thrive despite the risk of offshore harmful algal blooms.
Consistent HAB monitoring occurs in state waters, but it will also be necessary offshore to support aquaculture there. Under the law, areas used for commercial shellfish farming are routinely sampled to ensure food safety. Blue mussels are considered an ideal bioindicator of an HAB event, as well as a candidate for farming, because although they accumulate biotoxins, they also clear them out faster than other shellfish.
Wikfors and Mizuta analyzed shellfish harvest closure data from Rhode Island, Massachusetts, and New Hampshire between 2006 and 2017. Rhode Island was the only state for which comparable offshore and coastal closure data were available. They found that the annual average days of closure were similar: 50 days for offshore and 54 days for coastal.
To investigate offshore HAB trends, they analyzed toxic algal population density in waters off the coast during the same period from data collected by the Woods Hole Oceanographic Institution. Some of these data were collected during research surveys in rapid response to reports of possible toxic algal blooms.
While HABs developed offshore every year, typically from April to late October, bloom size and concentration of harmful algae varied considerably from year to year. Of the areas studied, the offshore waters off Massachusetts have the highest risk of HABs. The data show that offshore and coastal farms would likely have similar risks of HAB closures. Over the period studied, HAB events did not increase in New England waters.
“People have been wondering if the HABs that occur offshore in the Northeast would prevent offshore farming from being successful,” explained Darien Mizuta, “In these datasets, I saw no indications that HABs would prevent offshore farming activity.”
Their findings also support previously published observations that toxic blooms usually start offshore and move with the currents to inshore waters. While it could be logistically challenging to expand consistent HAB monitoring to offshore waters, offshore farms could serve as monitoring stations. Coastal shellfish farms stand to benefit from consistent offshore biotoxin testing. Growers could be warned in advance that a harmful bloom was detected offshore and may reach the coast.
While obstacles must be overcome for commercial offshore mussel farming to thrive in the Northeast, Mizuta and Wikfors highlight the potential of a domestic offshore mussel industry. Mussel aquaculture in federal waters off New England would be an environmentally sustainable and economically viable step toward American seafood competitiveness, not to mention a delicious addition to the local cuisine.
For more information contact Kristen Jabanoski
