Manatees may be hard of hearing

MIAMI, Dec. 14 (UPI) -- Efforts to protect Manatees in Florida have not worked, possibly because the sea cows could be hard of hearing, a researcher says.

The Sunshine State has created manatee safety zones and slow wake waterways designed to protect them, but the sea mammals repeatedly get in the paths of boats and are slashed by propellers.

Florida Atlantic University researcher Edmund Gerstein has measured the hearing abilities of manatees for 17 years, trying to understand why manatees get in the way of boats, often several times.

"Underwater, especially in murky water, everything is related to sound," he said.

Gerstein said the specially marked zones where boaters must reduce speeds for manatees may actually be harming them.

Gerstein found that manatees cannot hear approaching boats moving between 4 and 6 miles per hour, or idling.

As of Dec. 5, boats had killed 80 manatees this year in Florida. At this time last year, 70 manatees had died after being hit.