A boy needed stitches after swimming in a man-made lake in Montreal. Did a fish attack him?

WARNING: This story contains graphic images of a leg injury.

Last week, George Mandl, an American vacationing in Montreal, took his eight-year-old son Max to Parc Jean-Drapeau for a swim.

It was a hot afternoon, and Max played on an inflatable structure anchored in the park's man-made lake.

As his legs dangled in the blue-green darkness, he felt a stabbing pain. He screamed and, when lifeguards pulled him from the water, his leg was bleeding.

"It felt like a kind of electrical pain, like that pain when something is just jabbed into you. It felt like a knife had just cut my leg," he said. 

The lifeguards and, later, paramedics and two emergency room doctors, said they had seen nothing like it in their lives: a pattern of semi-circular scrapes punctuated by deep lacerations had appeared around Max's knee. He appeared to have been attacked. 

"One minute you're just playing and the next you're at the beginning of Jaws," Mandl said in an interview. 

Anglers say it is possible a large, carnivorous fish attacked Max, but such attacks are incredibly rare. The nature of Max's injuries has confounded some experts and led to an investigation by officials at Parc Jean-Drapeau who are trying to answer the question: What happened to Max?

When she first saw the picture of Max's injury, Béatrix Beisner, a professor of biological sciences who studies lake animals at the Université du Québec à Montréal (UQAM) didn't believe it could have been a fish bite. 

"I don't really know of any fish in our area that might bite a human," she said. "The only one I really know of that might bite a human would be a snapping turtle and they're more likely to take a toe or a finger. Their mouths are not that large."

She theorized that Max could have scraped himself on something under the water: a piece of metal, perhaps, or a cinder block.

But the structure Max was on is inflatable and children play on it daily. A submerged hazard would likely have been spotted and removed.

Beisner changed her mind, however, and said it was "entirely possible" that a fish attacked Max once she saw images of people who had been bitten by muskellunge, otherwise known as muskie. 

Muskies are the apex predator of lake fish, according to Michael Lazarus, a professional muskie angler who spends most of the year guiding tourists around Montreal, casting for the fish.