Wild Atlantic whitefish struggle to survive in Nova Scotia

This is the sixth in a series of stories from CBC's Information Morning about species that are struggling to survive in Nova Scotia, and the people who have vowed to save them.

The only place left on earth where wild Atlantic whitefish can be found is at a three-lake watershed in Lunenburg County, N.S., and a South Shore environmental group says the species — a relative of the salmon — is on the brink of extinction.

The Bluenose Coastal Action Foundation says dams, the impact of acid rain and invasive species like the chain pickerel and Chinese mystery snail are playing a part in the Atlantic whitefish's dwindling population.

"Chain pickerel are non-native to our province. They are voracious predators, so they attack anything that moves from what our experience has been," Brooke Nodding, the foundation's executive director, told CBC Radio's Information Morning on Tuesday.

"They not only out-compete and directly predate on native fish species, they also predate on small mammals, amphibians, reptiles — anything that moves."

Linda Campbell, a professor of environmental science at Saint Mary's University in Halifax, specializes in aquatic ecosystems.

Campbell said Chinese mystery snails eat algae and can change the nutrient cycle of the lake.

"They're introduced through aquarium trades. A lot of people buy them as pets in the pet store. They don't want these aquariums anymore so they release what's left back into the lakes," Campbell explained through American Sign Language interpreters.

"The aquarium trade is one of the top sources of invasive species in our ecosystems across Canada."

Campbell said Chinese mystery snails are reducing the amount of food for other fish.

"We're finding them in more and more lakes than we realized. They might be more widespread than we really think," Campbell said.

Nodding said chain pickerel have been known to clean out watersheds quickly.

She said the foundation, which has been conducting content analysis of both smallmouth bass and chain pickerel for four years, once found two baby snapping turtles inside the stomach of a chain pickerel.

"They were still alive and we were actually able to reintroduce them back into the water. A small success story on our part," Nodding said.

Campbell said freshwater mussels are really important to lakes because they help filter the water, change nutrients in the lake and are also a source of food for many fish species.

"They are fundamental for many lakes across Eastern Canada, but unfortunately the numbers of many of those species are really going down," she said.