Whale Beachings Linked to Mysterious Heart Defect

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In contrast the two smaller species reach 12 to 15 feet (3.65 to 4.55 meters) in length, weigh 1,000 to 1,500 pounds (450 to 680 kilograms), and have a heart about three times larger than a human. All three species are found in deep oceans worldwide, where they hunt for squid.

The first step in understanding more about the pathology and causes of the disease affecting these elusive animals will be to systematically examine the hearts of stranded whales.

To this end Bossart's team are preparing a dissection manual, using techniques typically applied to human hearts. Harbor Branch is one of few facilities to house a necropsy (animal autopsy) facility large enough to rigorously examine 15-foot-long marine mammals weighing thousands of pounds.

Bossart plans to distribute the manual to members of the Southeast Regional Marine Mammal Stranding Network. The network's members include volunteers, universities, government agencies, and others who respond to, and keep records of, strandings.

Marine mammal pathologists have until now used inconsistent methods to sample and study whale hearts, which has slowed progress in understanding the condition. The dissection methods agreed upon at the recent workshop should remedy that problem.

Man's Toilet

It's important to know what parts of the heart are typically damaged, and when during an animal's life the disease strikes, said Ruth Ewing also of the NOAA Southeast Fisheries Science Center in Miami. Though stranded cardiomyopathy victims are usually adults, it's not known whether the illness strikes young animals and becomes progressively serious, or if it mainly appears in older individuals. Though they have no record of it so far, marine mammal researchers also want to know if the disease is turning up in other parts of the world.

"We want to determine what's causing the cardiomopathy because right now we only have a list of possibilities," said Bossart. These include genetic defects as in the majority of human cases, but nutritional deficiencies, toxic pollutants, and viral infections could all also be responsible.

There have been increases in many illnesses found to harm marine mammals over recent decades, said Bossart. These include new infectious diseases, viral and bacterial, and also cancer—previously very rare in whales and dolphins.

"We may be seeing the effects of man's poor stewardship of the ocean," said Bossart. "The seas have been used as man's toilet for centuries, and now it's starting to catch up with us."

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Killer Whale "Willy" Shows Reluctance to Be Free
Scientists Mount Assault to Save Endangered Right Whales
Rescuers Fail to Free Entangled Whale off U.S. Coast

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