The 32nd annual Chantry Chinook Classic is now underway.
It started at one minute after Midnight on Saturday morning and continues until Noon on August 9th.
More than 2,000 people are expected to take part again this year.
Co-Chair Brian Lang says the prize for the largest salmon this year is $15,000, while the top prize for the biggest trout is $6,000.
The top salmon last year was around 23 pounds.
Lang says there are numerous other prizes during the derby and there are special days with a kids day on August 1st, and Ladies Days on the two Sundays during the event.
The Chantry Chinook Classic covers an area from Point Clark to Dyers Bay on Lake Huron, and from Lion's Head to Colpoy's Bay on Georgian Bay.
As part of the Derby, there's an "All You Can Eat Fish Fry" on Saturday August 8th from 4 PM until 8 PM at the Kincardine Harbour.