The entire global population of Atlantic whitefish is restricted to a single watershed in southern Nova Scotia, which is as alarming a statement as I am capable.
They used to be more widespread, of course, but the onslaught of impassable dams and invasive species destroyed their strongholds on the Tusket River, Yarmouth, and have prevented them from populating the Atlantic coast, as some once did. Our surviving whitefish live a strictly freshwater existence, in three lakes on the Petite Rivière, Bridgewater.
These lakes are the Hebb, Milipsigate and Minamkeak in ascending order. Invasive Smallmouth bass and Chain pickerel have already inundated the lower two, consuming whitefish and whatever else crosses their path. The hold of the whitefish on this watershed is so tenuous that a living adult hasn’t been seen since 2014. Only their young have been reliably caught each spring, tumbling over the dams which still subdivide the Petite Rivière.
“Once the pickerel are in Minamkeak Lake, which they will be before too long, it’s a countdown to extinction,” said Andrew Breen of the Bluenose Coastal Action Foundation. He ranks among the most active whitefish advocates I know, and works daily to prevent their disappearance through on-the-ground research and conservation. He’s the one cutting open Smallmouth bass and recovering partially digested whitefish from their stomachs. One time, inside a Chain pickerel, he found two baby turtles, alive and well.
On my first visit to the Petite Rivière Andrew made it very clear the watershed was no longer safe for Atlantic whitefish. Bass and pickerel are being removed from these lakes by the thousands, but by the federal government’s own admission, they repopulate too quickly to be eliminated outright.
“We need to be looking at other watersheds free of invasive species where we can try introducing a few whitefish, somewhere they might persist,” Andrew told me. “They haven’t got much time left.”
This has been attempted, of course. In 2000, a captive breeding program at the Mersey Biodiversity Facility in Milton, Nova Scotia, was founded with five adult whitefish taken from Petite Rivière. Between 2005-2008 some 12,000 captive raised whitefish were introduced to Anderson Lake in Dartmouth – a choice Andrew considers uninspired – and from 2007-2009 another 12,000 were released downstream in the Petite Rivière, in hopes of restoring their seafaring nature.
But with the abrupt closure of the Mersey Biodiversity Facility in 2012 by the Harper government, this captive breeding program was cancelled before it could produce meaningful results. The 12,000 released in downstream Petite Rivière apparently didn’t take, and more recent monitoring of Anderson Lake showed a complete absence of surviving whitefish.
A Second Last Ditch Effort
That brings us to this spring, when the fragility of this population forced the Department of Fisheries and Oceans to take 28 whitefish youngsters – collected by Andrew and his colleagues – to the Coldbrook Hatchery.
In a conversation with Alain Vézina, regional director of science with DFO, he called these 28 whitefish (25 of whom survived the summer) a “risk mitigation measure.” In short, they were trying to get all their eggs out of one basket. But no plan was in place for these young whitefish when they arrived; in fact there still isn’t one. The only certainty is that they cannot stay at Coldbrook.
Alain explained that this hatchery is at capacity and is not ideal for the storing of whitefish. They will be moved at the end of October, he said, but where they will go is a matter of ongoing debate. Will they be sent to a new watershed, a different facility, or be dumped back into their lake of origin? A decision from the regional director general, Mary-Ellen Valkenier, is forthcoming as of press time, Wednesday, Oct 10.
The biggest question on my mind is this – will DFO take advantage of the whitefish maturing at Coldbrook Hatchery and re-establish a captive breeding program, or will the opportunity be missed by releasing them?
Alain said more must be learned about the needs and behaviours of whitefish in their native habitat before a second captive breeding program can be attempted, whereas Andrew doubts a steady supply of whitefish infants await capture in coming years. Maybe next spring he will find none, he said, a frightening possibility. Study in the wild and breeding in captivity both seem necessary to me at this point, carried out simultaneously so that each can compliment the other as we hold back oblivion.
Into this mess of opinions and priorities has stepped Dalhousie University and geneticist Paul Bentzen who, on Friday, Oct 5, offered to take these whitefish and bring them to maturity at Aquatron, the university’s state-of-the-art aquatic research facility. Once old enough, captive breeding could begin. The official line from DFO is that they’re “open to exploring this option with Dalhousie.”
The fate of these captive whitefish will be decided at the end of October, and perhaps the fate of the species with them. Extinction is everyone’s business. It may not feel that way in the heart of farm country, on a city block or in the comfort of your living room, but the unraveling of our biosphere is acceptable under no circumstances, not for the North Atlantic right whale, not for the Southern White rhino, not for the Florida panther and not for the Atlantic whitefish.
Let’s keep a close eye on Coldbrook.
Zack Metcalfe is a freelance journalist, author, and writer active across the Maritimes. This article was originally published with the South Shore Breaker.