Why this big fish caught in downtown Toronto is a big deal for the environment

Will Sampson has been fishing in Toronto Harbour for his entire life and he couldn't believe what was happening.

The water was calm last Sunday morning as Sampson and a friend trolled their usual spots between Toronto Island and the downtown waterfront. A layer of fog still covered the city's towering skyline.

With the CN Tower and other Toronto landmarks just a few hundred metres away, Sampson landed a big fish rarely seen in the big city.

"It was definitely a shock and we knew we had caught a unicorn."

At first Sampson thought he had a large pike, a species more common to the area. But as the fish, which was just over a metre long, emerged from the water, he got a closer look at its lighter colours and spots — features that are typical of muskellunge, commonly known as muskie. 

"That's when we both just lost our minds," Sampson said.

"We actually caught one in downtown Toronto, you know. You look to your left and there's four million people in condo buildings and we're down there with a 43-inch muskie in the net."

It wasn't there long. After snapping some photos, Sampson returned the fish to the water. He didn't have the proper scale to weigh such a large muskie but guesses it was just under 20 lbs or around nine kilograms.

It was certainly a first for Sampson, 31, an experienced angler and fishing guide with his family-run business Detour Fishing Charters.

But it's also a rare catch for the experts who closely monitor the species of fish living in the waters around Canada's largest city.

"Catching a muskie in Toronto Harbour is super uncommon," said Rick Portiss, a senior manager of aquatic monitoring and management at the Toronto Region Conservation Authority.

"We've never had one in our catch over 30 years of environmental monitoring on the Toronto waterfront," he added.

Portiss says muskie are more commonly found in other parts of Lake Ontario, including near the St. Lawrence River and the Niagara Region.

Dating back to the 1800s, it was once a thriving species in the Toronto area. But Portiss says over two centuries, muskie habitat was destroyed as the city's waterfront was iurbanized.