Sperm Whales Drawn To Waters Off Mississippi River Delta

COLLEGE STATION, Texas, 28 May, 2001 -- When people think of the
Mississippi Delta, a few
things are likely to come to mind -- jambalaya, New Orleans jazz,
riverboats, cotton, swamps and sperm whales. Sperm whales?

Researchers have found that endangered sperm whales frequent the
deeper waters off the Mississippi Delta. Scientists estimate that at
least 530 sperm whales can be found in the northeastern Gulf of
Mexico.

In a Texas-Sea-Grant-funded project, Texas A&M University at
Galveston marine biologists Randall Davis and Bernd Würsig will use
satellite tracking, direct observation, genetic analyses and
photographic identification to learn more about these large marine
mammals that live so close to the coast.

Davis said coldwater eddies and the outflow of nutrients from the
Mississippi River may enhance the production of food for these marine
mammals and draw the animals nearer to coastal waters. The
Mississippi Delta region of the Gulf also has water that's several
thousand meters deep within 50 or 60 miles of the coast, he said, and
sperm whales are typically found
in these deeper waters along the continental shelf.

"The unique aspect of the Gulf is we have a continental shelf that is
only about 25 miles wide off the Mississippi Delta, so we have this
influx of freshwater nutrients into a deepwater environment very
close to the coast," he said.

While this area of the Gulf of Mexico is popular with sperm whales,
it is also home to a lot of oil and gas exploration. These
activities, and the increasing boat traffic they bring, may be a
cause for concern as far as their effects on the region's whales, he
said.

"Basically, we probably have a breeding population of endangered
sperm whales right in the middle of one of the hottest areas for
offshore oil development in the continental U.S," Davis said.

As part of the study, researchers will tag whales with tracking
devices that will follow the movements of the whales and record
information on how often a whale dives -- which can be linked to
feeding -- the duration of the dive and the depth of the dive. When
the whale surfaces, the device relays the information back to
researchers via satellite.

This information will help researchers learn more about the feeding
behavior of sperm whales, Davis said. Currently, they can only get
this information from observing sperm whales feeding and analyzing
the stomach contents of a whale -- neither of which is easily done.

"Without being able to make direct observations on these deepwater
whales, it's surprising how little we know about their natural
history," he said.

The project is set up as a basic science study that looks at the
natural history of sperm whales in the northern Gulf of Mexico.
However, Davis said the study's findings would likely be of interest
to the Marine Mammal Commission, National Marine Fisheries Service as
well as the Minerals Management Service, which oversees development
of offshore oil and gas deposits.

The Endangered Species Act requires officials to monitor not only oil
pollution but also noise pollution, which comes from boat traffic and
seismic activity that is used to search for oil.

http://www.sciencedaily.com/releases/2001/05/010525072138.htm

Source:National Sea Grant College Program
(http://www.mdsg.umd.edu/seagrantmediacenter/)