Saving Salmon
Saving Salmon
Inspiring the next generation of Atlantic Salmon conservationists


Pesticide Use a Major Problem in Open-Pen Aquaculture


By Tom Cheney with photographs by Nick Hawkins

This month, a New Brunswick salmon aquaculture company, Northern Harvest Sea Farms, was charged with a violation of the province’s Pesticides Control Act. That quite likely means the company illegally dumped toxic chemicals into the Bay of Fundy. It’s not the first time this has happened. In 2013, Kelly Cove Salmon, a division of Cooke Aqua, pleaded guilty to depositing Cypermethrin in the bay, killing hundreds of lobsters. Cypermethrin is an agricultural pesticide and its marine use is banned in Canada. (1)

It’s true that these may be isolated cases of industry players behaving poorly. They might also be the rare instances in which they got caught. Here’s the thing: when it comes to open-pen salmon farming, drugs and pesticides are just part of the game. And most of the time, the chemicals are deployed in ways that are perfectly lawful. But, as Fundy baykeeper Matt Abbott puts it, the compounds used by the industry are deeply concerning — even when used legally. (2)

Pesticides used by the aquaculture industry target sea lice, a type of parasitic crustacean that proliferates in the high density conditions where the fish are raised. When these chemicals are released into the ocean they kill larval crustaceans that form the foundation of marine food webs, including commercially valuable species such as lobster.
Salmon aquaculture isn’t going away. It can and should be a provider of healthy and sustainable protein, good jobs, and much needed economic activity. But its future isn’t in the ocean.

Which should make us ask: what’s going on in this industry that requires toxic chemicals to be thrown into sensitive marine environments with such frequency and liberal abandon? Well, it’s simply unnatural for Atlantic salmon to be packed into sea cages in such tight quarters. Sea lice occur normally on wild salmon, and rarely in numbers sufficient to cause harm. They die soon after the fish enter freshwater systems to spawn. But in the crowded open-net pens, the lice easily proliferate and can kill adult salmon. 

For years the industry added a chemical called “Slice” to fish feed, which kept sea lice at bay. But nature is nothing if not adaptable. The exact nature of the Northern Harvest violation is unclear, but Kelly Cove used Cypermethrin in an attempt to contain a Slice-resistant lice outbreak. The firm had sales greater than $165 million in 2013, making the $500,000 in fines just a slap on the wrist — the cost of doing business.

A day after the Northern Harvest charges were made public, Cooke Aqua proudly announced that it was testing a “Thermolicer” in the Bay of Fundy. That’s a device that exposes salmon to very warm water for a few seconds — long enough to remove sea lice but, apparently, harmless to the fish. The industry knows the public is watching and that it must reduce its dependence on chemical pesticides. 

A non-toxic lice treatment is probably a step in the right direction. But it’s just not enough. It does nothing to address the impacts of aquaculture escapees on wild salmon. It does nothing to combat other fish farm diseases, like Infectious Salmon Anemia. And it does nothing for the waste and detritus from open pens that blanket the seafloor, choking marine life. 

Salmon aquaculture isn’t going away. It can and should be a provider of healthy and sustainable protein, good jobs, and much needed economic activity. But its future isn’t in the ocean. The company will appear in court on May 15th. Stay tuned for an update on the charges, and come back soon for our account of the benefits of closed-containment aquaculture.


 1 -

 2 -