Following farmed salmon escapees

When I attended a couple sessions on aquaculture at the Maine Fishermen’s Forum this spring, there was a lot of excitement about the future of the industry in Maine.  It’s understandable. Thanks to its well-known lobster industry, Maine has made itself into a brand for sustainable (and delicious) seafood, it’s close to major markets like Boston and New York, and can boast clean waters: In other words, it’s a marketer’s dream come true.

It’s not just Maine, but on all coastlines that aquaculture is growing or at least touted as the next big thing. Thanks to new rules allowing aquaculture in federal waters, offshore mussel farms have been approved off Southern New England and California. Additionally, oyster aquaculture has helped maintain watermen on Chesapeake Bay; and there continue to be yearly predictions that finfish farming will start up in the Gulf of Mexico.

But aquaculture’s success does not just depend on reaching big-city markets, providing jobs and funding farms. It also has to be compatible with its surrounding environment. In places like Southeast Asia, for example, overcrowded shrimp farms have not just hurt the ecosystem, but also led to diseases like early mortality syndrome that have devastated the industry in some areas. Even in places where best practices are followed carefully, there are understandable risks in introducing a non-native species (though it’s important to note that some filter-feeders like mussels can actually be good for the water).

A recent initiative is trying to better understand that risk. Researchers in Canada have started a three-year experiment tracking escaped farmed salmon from open-water fish pens. The project records the behavior of escaped salmon from farms on the south coast of Newfoundland that have been tagged and released into the wild.

“What we do is simulate escapes,” explained Dounia Hamoutene, a research scientist with Fisheries and Oceans Canada, in a video about the project (above). “We have a certain number of fish that we tag, and then we have deployed receivers in some strategic areas, and we basically detect whether they went through that area or not.”

Some of the questions the researchers are trying to answer through this work are where the salmon go, how fast they are going, whether they are reaching rivers, and if they are able to be recaptured.

The biggest concern is what effect such escapees will have on native salmon if they interbreed: Will such interbreeding alter the genetic makeup of the native species and hurt their chances of being successful in their native environment? According to the researchers, this information will help them better manage the industry.

Of course, I’m also wondering what happens if they find out that escapees threaten the survival of local salmon? What then? But at least this research acknowledges that aquaculture can have an effect on its environment and tries to find out what that might be.

Caption: Canadian researchers are tracking what happens when salmon escape from open-water pens. Youtube screenshot.


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