Mussels and seaweed new mix with fish farms

Deer Island residents have been getting some additional work as a result of a new approach to salmon farming that Cooke Aquaculture has been helping to pioneer.

Nell Halse, vice president of communications for Cooke Aquaculture, headquartered in Blacks Harbour, says the company has been working on growing mussels and seaweed on salmon farm sites for the past five years as part of an integrated multi-trophic aquaculture approach to fish farming. With the mussels now being harvested, a small salmon processing plant at Lord's Cove, Deer Island, has been opened up for processing, with three to four people employed. Although the work is seasonal at this time, with the plant only expected to operate until the end of April, Halse says Cooke Aquaculture would like to have the plant running year-round. The plant, which has been in operation for a couple of months, is expected to reopen in September or October when the shellfish season opens again in the Bay of Fundy.

The mussels are being grown at Cooke Aquaculture's fish farm sites in the Back Bay area that are using the multi-trophic approach. "Our intention is to grow mussels on many more sites," says Halse, noting that the company is also looking at its Maine fish farms. Regulatory approval will be needed for growing mussels and seaweed on those sites.

Halse says the company is pursuing the growing of mussels and seaweed for two reasons: to be able to market additional products and to lessen any environmental impact from salmon farming. Although Cooke Aquaculture uses underwater cameras and automated feeding systems to limit any excess feed being placed in the water, Halse says that salmon farms do result in nutrient loading of the water from both feed and feces. Species such as mussels and seaweed extract nutrients from the water and thus lessen the impact from nutrient loading.

Research on integrated multi-trophic aquaculture is being conducted by a team led by Dr. Thierry Chopin of the University of New Brunswick and Dr. Shawn Robinson of the Department of Fisheries and Oceans' Biological Station at St. Andrews. According to the website of the University of New Brunswick, through the polyculture approach "some of the food, nutrients and energy considered lost in finfish monoculture are recaptured and converted into crops of commercial value, while biomitigation takes place. In this way all the cultivation components have an economic value."

"The meat yield is excellent," Halse says of the mussels grown at the salmon farms. "We get very positive feedback from our customers."

For the growing of seaweed, the company still is working on developing markets and more efficient harvesting and drying methods. Cooke Aquaculture has been farming two species of kelp at its sites: Laminaria and Alaria.