US Navy and Whales
This is the VOA Special English ENVIRONMENT REPORT.
In March of the year Two-Thousand, seventeen large ocean animals mysteriously appeared on the coast of some of the Bahama Islands. The islands are near the American state of Florida. The animals were small whales that live only in the ocean and cannot survive on land.
Seven of the whales died. Rescuers pushed the other ten whales back into the Atlantic Ocean. Ken Balcomb supervises the Marine Mammal Survey on the Bahamian island of Abaco. He said the first whales appeared near his research station. Mr. Balcomb knew that he needed to save tissue from the dead whales to find out why they had left the sea and died.
He cut off the heads of some of the dead whales. He then froze the heads to protect their tissue. Mr. Balcomb took the frozen whale heads on a passenger airplane to Boston, Massachusetts.
He took the whale tissue, weighing hundreds of kilograms, to Darlene Ketten. Mizz Ketten is an expert in whale biology at Harvard University in Cambridge, Massachusetts.
She used an electronic recording device to examine the whales' heads. She found that they had suffered severe damage and bleeding in their ears and around their brains.
The researchers decided that the whales had suffered from tissue damage caused by an extremely loud noise. The researchers at first thought that some natural event had caused the sound. However, the incidents happened at the same time that the United States Navy was testing an underwater listening device in the area. The device created an extremely loud sound in the ocean.
Sound moves more effectively through water than it does through air. Sound is measured in decibels. Sounds that measure one-hundred-eighty decibels can cause tissue damage in ocean animals. The Navy's tests created sounds of about two-hundred-thirty decibels. These sounds were one-hundred-thousand times louder than the level required to cause harm to ocean animals.
Scientists are not sure if the whales were killed by the sounds or if the sound-related injuries damaged their ability to swim safely. The Navy and the National Marine Fisheries Service wrote a report about the incidents. The Navy says it has changed the way it tests underwater sounds. It also says it will spend nine-million dollars to study ocean animals.
This VOA Special English ENVIRONMENT REPORT was written by Mario Ritter.