Fish hatcheries in Sudbury are facing a difficult year, as many of their fish are dying rather than going into northern lakes.

“They're notorious for cannibalism,” said Shane Wood, community hatchery co-ordinator with the Ontario Federation of Anglers and Hunter.

“So if there is not enough food in a rearing pond, or they get too large of a size, they actually start eating each other.”

More than half of the province's 23 walleye hatcheries are located around Sudbury.

A combination of severe winter weather, along with large numbers of tadpoles is also to blame for the decline in walleye fry.

walleye fry and tadpoles

Tadpoles compete for the food given to walleye fry at the hatchery. When the fish are hungry enough, they'll resort to eating each other. (Marina von Stackelberg/CBC)

At the Chelmsford community hatchery, Mike Wilson said baby frogs have been eating the fish food he puts out.

“They're laying their eggs in the ponds, and then they're hatching. I've walked around the pond looking for the fry and all saw was pollywogs,” he said.

Of the 400,000 eggs they harvested this year, Wilson only released 8,000 fry.

And it's not just frogs to blame. Cannibalism among the fry is also affecting the hatchery’s efforts.

Wilson said he'll keep his remaining walleye fry until September with the hope the delay will help increase their chance of survival.

The 12 million walleye grown in Ontario hatcheries are vital to the fish supply, Wood added. Despite being the fish most in demand by anglers, walleye are one of the most difficult to raise.

“If they stopped stocking these put, grow, and take fisheries, there would be no fisheries for anglers to enjoy,” he said.

community hatcheries in Ontario, 2013

The locations of community hatcheries in Ontario as of 2013. The yellow dots are the walleye hatcheries. (Shane Wood, Ontario Federation of Anglers and Hunters)