(AP) -- Tags, tissue samples and sound are among methods being used on a scientific cruise to study the Gulf of Mexico oil spill's effects on whales and other endangered animals.
The National Oceanic and Atmospheric Administration research ship Gordon Gunter returned to the waters Thursday after stopping in Pascagoula, its home port, for equipment and supplies.
As part of the study, listening buoys will remain on the sea floor for months, letting researchers track changes in what kinds of marine mammals show up and what they're doing as the amount of oil changes through the fall.
Cornell University scientists will lower a dozen units all around the Gulf to listen for sperm whale clicks and Bryde's (BRU-des) whale calls. Since whales use different clicks and calls while communicating, navigating and finding food, scientists can tell not only what species are around, but what they are doing.
A new technology that can record all marine mammal species living in the Gulf, including beaked whales and a variety of dolphins, is being deployed by a group from Scripps Institution of Oceanography of the University of California San Diego.
One unit is already in place near the sunken drilling rig Deepwater Horizon, and three more will be set in areas getting other amounts of oil.
Recording sounds from all the mammals living in the Gulf will provide a more complete picture of the ecosystem's health, said Dr. John Hildebrand of Scripps.
NOAA scientists will collect biopsies from sperm whales and other marine mammals, and will track where and how many there are by sight and - with towed underwater microphones - by sound.
Oregon State researchers hope to tag up to two dozen sperm whales near the wild well. The satellite tracking tags will tell the scientists whether the spill affects the size of the whales' home range and their movements within feeding areas.
Tagging healthy whales from a number of different groups will let him see if their movement patterns have changed. Researchers will also try to tag whales in the spill's projected path, to see what they do when the oil arrives.
The studies began in mid-June and the research ship is scheduled to return to shore Aug. 4.
Explore further: Ice loss from West Antarctica on the increase