Conservationists are converging on central New Brunswick after the confirmed identification last Thursday of an invasive smallmouth bass in the Southwest Miramichi River.
If established the fish could become a major threat to native Atlantic salmon in the river.
The fish was first spotted, and contained, in Miramichi Lake a decade ago.
Since then the federal Department of Fisheries and Oceans and conservation organizations have operated a program to prevent smallmouth bass from making their way from the lake into the river itself.
Spokesman Etienne Chiasson said DFO is now working with conservation partners to evaluate options.
"It is not clear if the smallmouth bass recently discovered below the Miramichi Lake fish barriers is an escapee from the Lake, or a new introduction, " he said. "Ultimately humans are responsible for the introduction of this species in the Miramichi River system."
Following a report that a smallmouth bass had done just that and was caught by an angler in the river Aug. 16, Canadian Rivers Institute biologist Allen Curry conducted a snorkelling survey in the same area, about eight kilometres downtstream from the mouth of a brook fed by the lake.
On Aug. 22, he found and photographed one fish.
Confirmation that smallmouth bass are now in the river was greeted with alarm by Nathan Wilbur of the Atlantic Salmon Federation and Mark Hambrook of the Miramichi Salmon Federation.
They fired off a joint letter to senior Fisheries officials Serge Doucet and Doug Bliss.
"At this point all we know is that there is one fish in the river," said the letter. "This warrants immediate and intense further investigation for other individuals, multiple age classes, young-of-the-year, distribution, etc. One fish is one fish until we learn more."
The Atlantic Salmon Federation's Neville Crabbe said there's plenty of evidence already from research on New Brunswick's southern rivers, including the St John, that smallmouth bass feed on young salmon.
"There's a biological effect that's indisputable," Crabb said. "It would be another threat to a native population that they just don't need. It would also fundamentally change the character of the river itself."
Crabbe said that beginning Wednesday, a survey of the river using nets is planned for the McKiel Brook area, where the fish was spotted.
That will be followed by electrofishing surveys up and downstream of where Allen Curry's fish was spotted.