The Canada Day long weekend proved deadly in Ontario as police responded to numerous fatal accidents in cottage country and on provincial highways.

On Monday morning, Durham Regional Police located the body of one of two men missing in Lake Scucog after a boat collision on Friday night.

Police had searched for the two men, a 49-year-old from Thursonia and a 38-year-old from Washburn Island, after their boat collided with another watercraft about 200 meters east of Scugog Island's north shore.

Both boats were found and the occupants of the other boat made it safely to shore following the accident.

Police said they recovered the body of the missing 38-year-old man at about 9 p.m. on Sunday, but are still searching for the 49-year-old man that was with him. The identities of the men have not been released.

An autopsy is scheduled for later Monday.

A 30-year-old Pickering man drowned after his rowboat capsized on McTaggart Lake in Central Ontario on Sunday morning. Provincial police from West Parry Sound said the man was with seven others in a five-meter aluminum boat when it capsized.

Divers recovered the body of Anusanthan Nadarjah after he failed to swim to the shore, about 75 meters away.

Police said an autopsy will be performed on Nadarajah's body on Monday.

On Lake Muskoka, several people fell into the water after two boats collided in Gravenhurst Bay at about 9:05 p.m. on Sunday evening. Several boaters were pulled from the water and transported to South Muskoka Memorial Hospital in Bracebridge.

A female child with severe facial and skull injuries was later transported via. air ambulance to The Hospital for Sick Children in Toronto. Another female passenger was taken to St. Michael's Hospital in Toronto with severe head and spinal injuries. 

A man involved in the collision was found to have had alcohol in his body and was issued a three-day license suspension.

On Muskoka Beach, a seven-year-old boy was swimming with friends when he slipped under the waves. He was rushed to The Hospital for Sick Children in Toronto in critical condition.

One-hundred meters away, 49-year-old Mark Houle hit a rock face in the midst of a cliff dive on Sunday afternoon. Houle was pulled out of Lake Muskoka by nearby cottagers and taken to hospital, where he later died.

A 21-year-old man also died while trying to swim across the Muskoka River in Bracebridge. An Ontario Provincial Police marine unit recovered the body Saturday afternoon.

Highway fatalities

The OPP says another seven people were killed on Ontario roadways over the weekend, including a 44-year-old Mississauga woman who died after her car hit a tree. The exact numbers won't be released until Tuesday. No fatal collisions were reported in the Greater Toronto Area.

Officials said traffic volumes over the long weekend were the highest they have been in about a decade, with major highways and side roads backed up for hours as motorists left for the cottage on Friday. Several thousand traffic offences were laid over the past three days.

With files from The Canadian Press and CTV Toronto's Colin D'Mello.