Migrating Leviathans
To the surprise of marine biologists, a significant number of endangered sperm whales appear to be making a permanent home in the Gulf of Mexico near the dangerously busy mouth of the Mississippi River.
Their emergence within a few miles of the Louisiana coast is remarkable because sperm whales rarely hunt close to shore or stay in one place for long.
Scientists are launching at least two research voyages to study the whales' habits and learn why these waters have become an oasis. The studies will cost at least $1 million and may continue through 2003. One venture will use a decommissioned anti-submarine ship that runs silently.
As they have done in earlier studies, biologists will attach digital tags to track the whales by satellite. They also will collect skin samples for DNA tests to determine whether the whales are newcomers or have lived in the northern Gulf for generations.
The presence of 500 or so of the leviathans - some of them bigger than a Greyhound bus - belies the northern Gulf's reputation as a growing "dead zone" of low-oxygen water where marine life is being smothered.
"The Gulf was thought to be a simple and unproductive ecosystem, but it is full of surprises," said Robert Gisiner of the Office of Naval Research, an arm of the Navy. "These great big, deep-water whales are living there year-round."
That is not necessarily welcome news. The sea south of New Orleans is a floating interstate highway, with whales squarely in the path of supertankers, barges, trawlers and warships.
The rare marine mammals could be on a collision course with the Bush administration, too. The northern Gulf is one of the world's most important oil fields. Drilling in deeper waters is a crucial part of the White House's plan to expand energy production.
Catastrophe lurks not only in collisions or oil spills. The real danger to the whales, researchers say, is noise.
The increasing industrial cacophony below the waves - propellers, diesel engines, seismic booms, grinding drills and sonar pings - could damage the whales' sensitive communications and navigation organs, with potentially fatal consequences.
"We didn't expect to be running into sperm whales right off the Mississippi Delta, in the middle of all this activity," said Randall Davis of Texas A&M University at Galveston. "Their endangered status is supposed to afford them additional consideration for their protection. But these whales have not yet received a lot of attention."
At least 45 rigs in the Gulf operate at depths of 1,000 to 10,000 feet. Sperm whales are among the few creatures that can dive there.
Industry officials say companies are exploring and drilling safely around the whales in compliance with the federal Endangered Species Act and the Marine Mammal Protection Act.
"Our vessels automatically shut down their seismic testing equipment as a precaution anytime they detect a marine mammal," said Thomas Michels, spokesman for the National Ofshore Industries Associations.
Scientists agree that no injured whales have been spotted so far.
"The real problem is that industry is moving into deeper water where there hasn't been activity before," said Bill Lang, senior oceanographer for the Marine Minerals Service, an Interior Department agency. "We don't know how sperm whales react to a passing ship or underwater seismic activity. No one is sure whether they are sustaining hearing damage."
Sperm whales were made famous by Herman Melville in "Moby-Dick." Nearly everything about them is super-sized. An adult male measures 50 feet long and weighs up to 50 tons. It can remain underwater for more than hour.
Two million sperm whales once roamed the oceans worldwide. Hunting reduced their numbers dramatically before a whaling ban was enacted 15 years ago. The sperm whale population now is estimated at 200,000.
Beginning in the 1840s, whalers' logs noted sperm whales in the Gulf. But they were largely forgotten. Scientists started noticing them anew during biological surveys in the 1990s.
Several factors are drawing the whales closer to shore, scientists believe.
First, the Continental Shelf plunges 1,000 feet just a few miles offshore. Sperm whales typically hunt in deep water and submarine canyons.
Also, swirling warm and cold currents mingle waters from the Atlantic and Caribbean. Biological diversity erupts where these eddies converge.
A third factor is the huge volume of freshwater pouring from the Mississippi River. It seeds the ocean with nutrients, spawning a rich food chain.
In recent years, fertilizer and livestock manure flushing from the nation's Farm Belt have triggered an ecological chain reaction that depletes the water of oxygen, suffocating marine life.
Yet the whales are flourishing on the deep-water edge of this "dead zone."
What are they eating? It is another question researchers will try to answer this summer. But according to Gisiner, surviving marine life may be hiding there, trying to avoid tuna and other speedy, predatory fish.
"Whales are expert oceanographers," he said. "They're having a field day."
By Joseph B. Verrengia
© MMI The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed