Two separate rescue attempts on Ontario lakes came to a grim conclusion overnight when marine units located the bodies of three young girls.

The body of a 13-year-old girl was pulled from Lake Ontario near Van Wagners Beach, near Hamilton, shortly before 2 a.m. on Wednesday after disappearing in the water more than eight hours earlier.

Hamilton police said the girl was playing with friends on a floating dock when she jumped into the water. A dive team recovered the body after an extensive search.

Tragedy on Musselman's Lake

Marine units also pulled the bodies of two missing girls from Musselman's Lake, northeast of Toronto, at around 2:30 a.m.

York Regional Police said the girls, 15 and 16 years old, had either jumped or fallen off a small dinghy and disappeared Tuesday night.

Kyle Jenkin, who was by the lake at the time of the drowning, said he believes he was the last person to see the girls alive.

Jenkin told CTV Toronto that he was getting ready to go water-skiing when he spotted the pair floating by on a dinghy.

"We commented on how nice the night was, how warm the water was and I wished them a nice night," he said.

A short while later, Jenkin said he was loading up his boat when he realized the girls were in trouble.

"I can hear one girl yell ‘Stop holding on to me, you're pulling me under,'" he said.

Jenkin said he tried rush into the water with his boat to help the girls but it took approximately 30 seconds to lower the vessel onto the lake. By then, it was too late.

"In those 30 seconds I watched those two girls drown," said Jenkin.

It is believed that one of the girls could not swim. It is also believed that neither girl was wearing a life preserver.

Memories of the incident haunt Jenkin, who still wonders if he could have saved the girls.

"You feel sick to your stomach and you spend the whole day questioning what you could have done better," he said.

Relatives of at least one of the girls were gathered lakeside as York Regional Police marine units recovered the bodies overnight. Insp. Chris Bullen said the bodies had not yet been identified.

Elsewhere, police and private divers were searching overnight for a 55-year-old Toronto man who was last seen Monday on Lake Joseph, near Parry Sound.

Police said Bradley David Griffiths, a co-founder of GMP Capital, was seen in distress in the water after a motor boat was found operating without a driver.

Drowning prevention

The recent drownings come during National Drowning Prevention Week, a time dedicated toward increasing the awareness of the dangers that swimmers face in pools and on the open water.

Last year 237 Canadians died from drowning, according to the St. John Ambulance. The aid group says families should take swimming lessons and learn first aid in order to ensure a safe environment.

Children should always wear life jackets and be supervised by an adult while swimming.

With a report from CTV's Michelle Dube and The Canadian Press