Coast guards on both sides of the Detroit River are hunting for the person responsible for several false mayday distress calls.

The U.S. Coast Guard says it's hearing the same man call mayday over radio airwaves several times a week. It's offering a $3,500 reward to the person who helps find the hoax caller.

It's costing time and money and putting people at risk, say both coast guards.

"Fake or not, we're required to respond and react as if we're ready to rescue somebody," said U.S. Coast Guard Lt. Justin Westmiller.

'Fake or not, we're required to respond and react.'— Lt. Justin Westmiller, U.S. Coast Guard

He said the calls last approximately eight seconds, not long enough for the coast guard to pinpoint the caller's exact location.

In the calls, the mariner claims his boat is on fire or sinking or, sometimes, both.

"My boat is on fire! And it's sinking, too!" the person says in one of the calls.

Westmiller said they need the public's help to find the person responsible for the bogus calls.

Canada affected, too

When the Canadian Coast Guard picks up the distress signal on the Canadian side, the Windsor Police, RCMP, OPP and the coast guard all react. If it's a bogus call, that means the response time for actual emergencies could be longer.

The Canadian Coast Guard boat is deployed from Amherstburg, south of Windsor.

Windsor and Essex County is surrounded by the waters of Lake St. Clair to the north, the Detroit River and Lake Erie to the south.

"Each time we deploy, it's thousands of dollars. It's not hundred of dollars, it's thousands of dollars," said Peter Barry, the Canadian harbour master in Windsor. "We're not talking just the fuel, it's the people involved in the search."

'Each time we deploy, it's thousands of dollars.'— Peter Barry, Windsor harbour master

Scott Salter is an experienced sailor, who has helped save people in distress.

He said it's disturbing to know people could be at risk.

"If there's only one coast guard vessel in the vicinity, they're going to travel out into the lake for the first call and the second call may be the call where the person is actually drowning or needs assistance," said Salter, the manager of the Riverside Marina on Windsor's east side.

Barry said maydays usually come from thrill seekers or people who are drunk.

In the U.S., it is a felony to make false distress calls. Penalties could include prison time, fines and reimbursement for resources spent searching for the caller.

In Canada, under the Radiocommunication Act, a person is subject to a fine of no more than $25,000 and a prison term of no more than a year, or both.