A Toronto lawyer has completed a strenuous trek across Lake Ontario to raise money for the fight against melanoma.

The event, called "Crossing for a Cause," is in honour of his friend, Douglas, who succumbed to the disease at age 29. The man conducting the difficult swim for charity, Michael McIsaac, hopes to raise $100,000 for the Douglas Wright Foundation. The fundraising efforts have so far garnered more than $76,000.

"Melanoma is the most common cancer among young adults but is treatable with early detection," McIsaac said. "We need to raise awareness rapidly so young people enjoy their prime years, not lose them."

McIsaac, 32, began his 51-kilometre journey in Niagara-on-the-Lake, Ont. He finished the swim in Toronto late last night.

Fittingly, the park where McIsaac concluded the trek is named after Marilyn Bell, a Canadian long-distance swimmer who endured gruelling conditions to complete her own swim across Lake Ontario in 1954.

Just over a year ago, 14-year-old Trinity Arsenault of St. Catharines, Ont., completed the swim across the lake. Before her, Annaleise Carr of Walsh, Ont., came ashore in Toronto after crossing Lake Ontario in 2012, also at the age of 14. The two teenagers are believed to be among the youngest ever to accomplish the feat.

McIsaac, a recreational athlete, has been training for 11 months to prepare for this incredible challenge while working full time as a lawyer.