This past week, the net of a fish farm in Washington state was damaged, releasing thousands of Atlantic salmon into Pacific waters. Of course, Atlantic salmon don’t belong there and can have disastrous consequences on the already-struggling Pacific salmon.

The oceans are being overfished and one solution to reliably bring fish to the grocery stores is to raise them on fish farms. On one hand, this is positive because it takes pressure off from wild fish stocks. On the other hand, the enclosures are often directly in bays and can affect wild fish and ecosystems.

Something fishy

The fish farm that broke is owned by Cooke Aquaculture and the net in question contained 305,000 Atlantic salmon. It is located in Washington state near the San Juan Islands. At first, between 4,000 and 5,000 fish were confirmed by the company to have escaped. However, they have recently admitted that the number could actually be much higher than that. Cooke Aquaculture needs to wait until the tides improve to really see what the damage was.

Fish farms are often right in the middle of bays and pretty exposed. Image credits: Frank Vincentz.

The company blamed high tides and even the solar eclipse. However, the real problem is that Cooke Aquaculture just bought the farm last year. The fish farm is 30 years old and not up to date on safety standards. It was scheduled for upgrades and already showed trouble last month. In July, emergency work was needed to stabilize nets after they were moving in the currents. The company was planning to install new up-to-date technology after this harvest.

According to tide charts, the tides and currents were nothing unusual. Of course, an eclipse wouldn’t have any special effect, just the presence of the new moon could mean higher tides and currents. But there is a new moon every month and the nets should be built to withstand the currents that come with it.

Aftermath

Local fishermen who catch Pacific salmon have been catching Atlantic salmon in their nets already. Indeed, anglers are encouraged to catch as many of the escapees as possible. Many are worrying about the negative consequences that these escapees could have.

Atlantic salmon don’t belong on the west coast and are an invasive species there. Their consequences on native fish and ecosystems are unknown; they could spread disease, prey on or compete with native fish. Atlantic salmon could also cross-breed with the threatened Pacific salmon.

Atlantic salmon have been caught in the past few days where they don’t belong. Image credits: Rupert Fleetingly.

One thing that could limit the escaped fish survival is that they are domesticated and perhaps aren’t so good at living in the wild. However, it has been found in the past that escaped farmed fish mate with wild fish. Not much is known now about their impact but Professor John Volpe has found in his research that Atlantic salmon can survive and produce offspring in the Pacific.

Perhaps it’s not a good idea to raise Atlantic salmon in the West, especially in exposed enclosures. Thousands of Atlantic salmon have already been released in the Pacific before, in the 1900s and 1990s. Now, this escape is particularly serious because it threatens Pacific salmon when they are already struggling to survive against human-caused changes in the environment. Here’s to hoping the Pacific salmon pull through.

Enjoyed this article? Join 40,000+ subscribers to the ZME Science newsletter. Subscribe now!

Like us on Facebook

Your opinion matters -- voice it in the comments below!