Why poisoning this river is seen as good news

Then they did it again. And again. And again. When they were done there, they moved to another spot along the river and repeated the whole process.

They were, to a person, in good humour; the sun beating warm on their shoulders, and the river water cool around their feet.

“We won’t get all the fish, but we’ll do our darndest to get as many as we can,” said Nathan Wilber, of the Atlantic Salmon Federation. Several moments later, he was removing salmon one-by-one from the back end of a fyke net and passing them to people who would start them on their journey.

Once their work was done, those gathered knew, the rescue mission would shift to its next stage.

That comes Tuesday, when a poison will be poured into this portion of the river, and almost everything left in the water with gills will die.

Web editor’s note: protests temporarily delayed the use of rotenone.

The poison — rotenone, it’s called — is a temporary one.

Rotenone is a natural toxin derived from the root of bean plants in South America and the Pacific regions, used for centuries by Indigenous populations to catch fish. While it’s highly toxic to fish, it has low toxicity to birds and mammals.

It deteriorates rapidly with exposure to light, heat and oxygen, and biologists have picked this time of year — with warm water temperatures and low water levels and favourable life-cycle stages — with that in mind.

By the time water flows the 10 kilometres downstream to where the salmon have been released — below a recently erected barrier preventing them from swimming back upstream — the toxin will be impotent, helped along that path by a release of potassium permanganate into the river along the way.

The fish that wasn’t supposed to be there in 2008 was a smallmouth bass, an invasive species. Though they’re not native to the Maritime provinces, they can now be found in more than 100 lakes and rivers in New Brunswick.

That’s problematic because what’s in the area is the Atlantic salmon — the pearls of the Miramichi watershed. The New Brunswick river has one of the largest salmon runs on the planet and attracts visitors and fishers from across the world.

But those salmon numbers have been dwindling. In 2020, according to the Miramichi Salmon Association, there were 15,000 small and large Atlantic salmon in the Miramichi River. That’s a worrisome drop from the 75,000 recorded there in 2011, and one that has a significant economic impact on the region.

“If a species like this was to get established in these headwater areas, that’s a new pressure that’s introduced … adding to the million other pressures that salmon are facing,” says Ward. “We fear that this might be the nail in the coffin for the species in the area.”

There’s an economic impact as well. A 2011 Atlantic Salmon Federation report — the most recent comprehensive study of the economic value of the Atlantic salmon — sets that value at $17 million. The salmon also creating 637 jobs, worth another $19.1 million.

In the 13 years since it was spotted in the Miramichi Lake, conservationists’ greatest fears have been realized — the smallmouth has migrated from the lake to the Miramichi River. In the lake, there were few if any salmon, but once the smallmouth invaded the headwaters of the Miramichi, where, to date, there have been no freshwater predators of salmon, the situation became much more dire.

This is why groups of salmon stakeholders with the catchy moniker “Working Group on Smallmouth Bass Eradication in Miramichi Lake” — which includes the North Shore Micmac District Council, the Atlantic Salmon Federation and the Miramichi Salmon Association — began developing an eradication plan for the smallmouth bass menace.

By 2018, despite having pulled some 6,000 bass out of Miramichi Lake, Fisheries and Oceans (DFO) was no closer to controlling the smallmouth population than before. And the feds were adamant about not using toxins to the eradicate the fish. At the time, they seemed more inclined to merely wait and monitor the situation.

In August that year, after having presented DFO with a plan to use rotenone in the lake, the Working Group hosted a followup meeting with federal officials in Moncton.

Neville Crabbe of the Atlantic Salmon Federation remembers well the moment in that meeting when Jim Ward, the general manager of the North Shore Micmac District Council stood up.

“‘Well,’ he said. ‘If you guys won’t do it, then we will.’”

“And then all of a sudden you have a really well-organized Indigenous proponent backed up by a fairly muscular and determined coalition of NGOs that just said, ‘We’ll do it,’” remembers Crabbe.

In May of this year, the Working Group finally got provincial and federal permissions sorted and began to put its massively ambitious, logistically complex plan into action.

It’s a task accomplished by rote in many other places in the country: in New Brunswick, Nova Scotia, Alberta, British Columbia and across the planet, most notably in Norway, where the government there adopted a 10-year plan to eradicate a parasite infecting wild salmon in the country’s rivers. The parasite was deemed capable of completely wiping out a river’s salmon population over the course of four to six years.

Beginning around 2013, after establishing gene banks for their salmon, the Norwegians dosed entire river systems with rotenone, killing all the wild salmon therein.

To date, of the 50 rivers infected, 32 have been declared parasite-free and have had salmon reintroduced. A further 11 have been treated with rotenone and are awaiting a potential all-clear.

There have been many weeks leading up to it, and many people involved in various facets of the eradication plan, but on treatment day, the Working Group will launch its operation in earnest.

There will be more than 100 people in 46 crews, all dressed in personal protective equipment monitoring on and along the lake and the river.