New Brunswick

Salmon groups hope to add poison to part of Miramichi River to kill smallmouth bass

Salmon conservation groups are now planning to temporarily poison several kilometres of the Main Southwest Miramichi River this September in an effort to eradicate invasive smallmouth bass there.

Plan would see part of Southwest Miramichi River temporarily poisoned

Nathan Wilbur of the Atlantic Salmon Federation is shown with invasive smallmouth bass caught in the Miramichi River downstream from Miramichi Lake. (Atlantic Salmon Federation)

Salmon conservation groups are now planning to temporarily poison several kilometres of the Southwest Miramichi River this September in an effort to eradicate invasive smallmouth bass there.

It's a major expansion of an original plan to use the chemical rotenone to kill off fish only in Miramichi Lake, near Napadogan.

The proposal still needs to be approved by Fisheries and Oceans Canada.

It's suspected the smallmouth were illegally introduced into Miramichi Lake about a decade ago and have become an established population there.  Continuous efforts by the Department of Fisheries and Oceans and other groups to eliminate them since that time have failed.

'Large undertaking'

Smallmouth bass - an invasive species that is not native anywhere in Atlantic Canada - can quickly turn to young salmon as a food source.

Concern turned to alarm for salmon conservation groups in the summer of 2019 when smallmouth were discovered in the Miramichi River, downstream from the lake.

The organizations have created a working group headed by the North Shore Micmac District Council. It includes the Miramichi Salmon Association, the New Brunswick Wildlife Federation and the Atlantic Salmon Federation.

"This is a large undertaking, it's novel, it's very direct," said Neville Crabbe, spokesperson for the Atlantic Salmon Federation. "I think it will set precedent for action in the province to protect our native species."

The plan would see rotenone, a natural substance made from the dried root of certain bean plants in equatorial regions, released into both the lake and a section of the river extending downstream as far as ten kilometres.

Representatives from Atlantic Salmon groups inspect a screen designed to prevent the escape of smallmouth bass from Miramichi Lake into the Miramichi River system. (Atlantic Salmon Federation)

Rotenone can kill fish within minutes. It has been effective in erasing invasive fish populations elsewhere in North America and other parts of the world.
 
It bio-degrades in water over a period of two weeks to 30 days or more, depending on conditions.

Crabbe said rotenone has been used successfully in dozens of rivers in Norway to deal with an invasive parasite that was killing off salmon populations.

If approved for use in the Miramichi River, the plan is to release it near the lake and later "neutralize" it at a selected point downstream by spraying the river water with potassium permanganate.

Meet with cottage owners

The salmon groups have scheduled a meeting with Miramichi Lake cottage owners for January 26 in Woodstock.

Crabbe promises no information will be withheld.

"What we can control is just being open, honest and transparent. I believe this meeting at the end of the month is a big step in that direction," he said.

Mark Hambrook, president of the Miramichi Salmon Association, says expanding the rotenone project from the lake to include a section of the river will also increase costs.

He says the discovery this fall of dozens of smallmouth bass downstream from Miramichi Lake leaves little choice.

He estimates it will cost as much as $1.5 million to do the work.  

About the Author

Connell Smith is a reporter with CBC in Saint John. He can be reached at 632-7726 Connell.smith@cbc.ca

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