There’s a lot that’s not natural in this environment for these fish, a critically endangered species known as Atlantic whitefish. Scientists estimate it diverged from its closest relatives 14 million years ago, and it was once found throughout Nova Scotia. But over the course of geological epochs, and in the human-scale epoch since colonization, this whitefish’s range has shrunk to just three lakes on Nova Scotia’s south shore — and to these tanks at a research facility known as the Aquatron, where much of the remaining hope for the species swims in languid circles against the current. “I am certain with every fibre of my being that there are more whitefish [at Dalhousie] than anywhere else,” Bentzen said.

A team of government scientists, academics and non-profits are working to save the remaining whitefish, and to expand their range by introducing them to new lakes. Yet their efforts have been stymied by ongoing degradation of the whitefish’s remaining habitat, and with funding that threatens to disappear — even as the state of the population grows more dire. In 2019 (an especially good year for the species) researchers found 251 larval fish for the captive breeding program. In 2024, they captured six. Environmental DNA sampling in the Petite Riviere watershed, near the town of Bridgewater, N.S., has only picked up whitefish presence once in the last few years.