Salmon groups push ahead with fish kill in face of COVID-19 emergency

New Brunswick salmon groups and First Nations are keeping an anxious eye on the calendar as COVID–19 threatens the arrival of a key U.S. expert invited here to help eradicate invasive smallmouth bass.

The bass - which are not native anywhere in Atlantic Canada - have escaped into the Miramichi River, where it is feared they could devastate native Atlantic salmon stocks by eating their young.

Brian Finlayson of California literally wrote the book on how to use rotenone, a product that kills fish within minutes. It has been effective in erasing invasive fish populations elsewhere in North America and other parts of the world.
 
It's poisonous to fish but bio-degrades in water over a period of two weeks to 30 days or more, depending on conditions.

The salmon groups are still hoping they will be able to apply rotenone in late August or early September in Miramichi Lake, where the bass appeared just over a decade ago, and in a 10 kilometre stretch of the Miramichi River itself.

"COVID is throwing a big stick in the spokes here," said Nathan Wilbur of the Atlantic Salmon Federation this week. "We need Brian here to do some training and help with the planning and execution of this."

The ASF held a virtual meeting, billed as a webinar, Wednesday evening to explain plans to treat the lake, river, and a small brook that connects the two.

The groups, led by the North Shore Micmac District Council, had originally planned to treat just Miramichi Lake, but broadened it to include a section of the river after the discovery last August that some of the smallmouth bass had made their way through a brook into the river itself.

The treatment plan will require approval from the federal Department of Fisheries and Oceans. The application to treat the river was only added to the original request to DFO on April 8, which may make it too late to treat the river into 2021.

If the Rotenone treatment is successful all smallmouth bass in Miramichi lake would be killed within hours, along with almost every other species of fish. A proposed recovery plan would allow the lake to repopulate with some fish species making their way into it via the brook.

Other, non-migrating fish species would be transplanted to the lake. Adult invertebrates are not expected to be impacted, nor are birds and insects.

"For the most part studies show that zoo plankton and invertebrates recover to pre-treatment levels the very next spring after treatment, or at least within a year," said Wilbur.

According to Finlayson, who participated in the online webinar from his home in California, the late August, early September window for treatment will give time for migrating fish like gaspereau to leave the lake for the annual return to the sea, while also providing warmer water, increasing rotenone's effectiveness, and reducing the amount of time it takes to dissipate.

He says camp owners will be able to begin using the lake three days after completion of the treatment, with the rotenone likely dissipated entirely within 30 days.  

Those statements do little to ease concerns for Trish Foster. Foster represents a group of camp owners on the 600 acre lake.

She's disappointed New Brunswick's Department of Environment and Local Government waived the requirement for an environmental impact assessment on the original application involving treatment of just the lake, citing the danger smallmouth present to native Atlantic salmon.

"None of our concerns have changed," said Foster.