Tests Lead to Hope for Dwindling Manatee Population


When's the last time you heard of a hearing test that had the potential of saving thousands of lives?

After puzzling for decades over why so many manatees are killed or seriously injured by boat propellers, Dr. Edmund Gerstein decided to test a theory with two manatees in captivity – that they couldn't hear the boats in time to avoid a collision.

The tests proved that the sea cows had very good hearing ability, but that it centered on high frequencies. This is bad news for the manatees because slower moving boats produce much lower frequencies that seem to confuse them, resulting in collisions.

While protected by law, there are only 3,500 manatees estimated to exist in the wild. Four in five of these manatees bear the scars of boating mishaps. So solving the mystery of the boat impacts will go a long way in saving those that remain.

Gerstein assembled a team to conduct trials on a high pitch boat alarm to test the response of wild manatees in restricted waterways near Nasas Cape Canaveral. Manatees are generally slow to move away from the path of a boat, but after 17 test runs with the alarm the results were clear; 100% of the manatees reacted long before the boat approached them.

In comparison 97% of over 65 silent test runs resulted in manatees that didn't react at all.

The alarm is considered a success, but now the task is to equip boats in manatee populated waters with similar devices. Gerstein states that the cost for these alarms would be about $125 and that many boaters would gladly pay since it will protect the manatees and allow them to reach a particular location faster.

Perhaps the real test will be to see how quickly the alarms are actually adopted by the boating public.

For more about the manatee hearing tests, you can watch the video Boat Alarm Could Save Manatees on the National Geographic news site.

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