July 7th, 2010
By Melissa Segrest
Green Right Now
There are more than 1,600 sperm whales in the Gulf of Mexico. Scientists are in search of them to test for the oil spill's impact. Photo courtesy NOAA.
An unprecedented gathering of marine mammal scientists and researchers, armed with the latest high-tech equipment, set to sea late last week to begin the first step in a multi-year study of the BP oil spill’s impact on whales and dolphins in the Gulf of Mexico.
As a matter of fact, this month-long mission would not have left port were it not for the fact that another research trip had already been planned for the 244-foot Gordon Gunther.
“This takes time to pull together. We were fortunate that we had academic partners come along and add some excellent capabilities. We moved rapidly to get people and equipment into place,” Lance Garrison said. Garrison is a fisheries biologist and the principal investigator for NOAA, the National Oceanic and Atmospheric Administration. The Gordon Gunther is among NOAA’s fleet of research ships
There are 21 species of marine mammals in the Gulf of Mexico, including endangered sperm whales and a small pod of Bryde’s whales. The 15 scientists on the ship (and a crew of almost 30) will collect small tissue samples from live whales and dolphins and attach satellite tags to an estimated two dozen sperm whales near the spill.
With them is an array of listening equipment from underwater microphones towed by the ship to compact, complex devices that sit on the ocean floor for months and measure the various clicks, long moans and whistles made by whales and dolphins as they move about, communicate and locate prey.
This level of research has not been conducted in the Gulf of Mexico before. Marine research expeditions in 2002 and 2005, when whales were tagged with electronic devices, has provided this group with baseline information about marine mammal populations and habitats.
Researchers already know that oiled ocean waters can be lethal to whales. Orcas that lived in the waters fouled by the Exxon Valdez spill more than 20 years ago died, and their numbers have still not increased to pre-spill populations.
The NOAA ship Gordon Gunter is carrying an elite group of marine mammal researchers and the latest in whale-detecting technology. (Photo courtesy NOAA)
Unlike the highly visible oiled birds found along the gulf coastline, the deep-sea marine mammals are only found far offshore.
Could some dolphins and whales already be dead?
In mid-June, a NOAA ship found a dead 25-foot sperm whale floating 150 miles south of Mississippi, and 77 miles from the spill. The cause of death has not yet been determined. There have been more dolphins: 56 found stranded from April 30 to July 2 in the spill area. Of those, five were alive, but three died. There was oil on several of the dolphins, but their cause of death is still unknown.
There’s no way to know about others, Garrison thinks. “Dead whales or dolphins may float on the ocean’s surface for a few days, but then likely sink.” he said.
That’s why this multi-faceted effort is so important. Without direct knowledge of deaths that may have already occurred, these marine researchers counting cetaceans — trying to determine their movement, feeding and habitats – will provide invaluable information on how the oil spill could impact their numbers for years to come.
“They’re going to be working along the Continental Shelf break, placing (ocean floor) buoys from 1,000 meters (.6 of a mile) to 3,000 meters (nearly 2 miles) deep, 50 to 150 miles offshore, from the Texas border to the Florida panhandle and just north of the Dry Tortugas,” said Garrison, who works at NOAA’s Southeast Fisheries Science Center.
Researchers from Cornell University, Oregon State University and the Scripps Institution of Oceanography are on the ship, along with NOAA scientists.
About two dozen of Cornell’s ocean-floor recording units will be deployed over a large area of the gulf, recording the sounds of sperm and Bryde’s whales and other cetaceans for the next four months.
Newer devices – High Frequency Acoustic Recording Packages, or HARPS – from the University of California’s Scripps Institution, until now have only been used in Pacific waters off California. These devices record both low frequencies of deep-water whales and higher-frequency sounds of dolphins and beaked whales.
A small pod of Bryde's whales live in the gulf in a remote area. (Photo by Isabel Beasley, courtesy NOAA)
The HARPS accumulate much more information. “After they are retrieved, the information is run through computer algorithms to identify the types of noises and correlate changes to seasonal movements as well as changes in the oil in the water. We will know if the animals move to avoid an oiled area,” Garrison said.
Small samples of whale and dolphin tissue – about 7 to 10 millimeters, less than the width of a dime and about 2 inches deep — are taken when whales are spotted. “We go out on a small boat with a modified air rifle that has a dart – the tip of the dart is very small. There are little hooks inside the tip that pull out a little skin and blubber as the dart rebounds,” Garrison said. Chemical analysis, for everything from genetics to pollutant exposure, begins when the ship returns in early August. Those first results will take three to six months.
Samples of some of the whales’ prey, such as deepwater squid, which could introduce toxic chemicals to the whales, also will eventually be tested for contaminants. On this trip, acoustics will determine the amount of fish, squid and plankton in the deep waters, as well as testing of the water itself.
“One of the things that has been difficult about some of this work is there aren’t necessarily good chemical metrics about impacts of this oil spill – that’s the subject of debate at the moment.
“We’re intentionally at an early stage in the process. What we would expect to see over time is perhaps an accumulation of things in tissues and we want to be in a position to track those changes. This is the first data point in a long series,” he said. The scientists will examine whales and dolphins over months and years, looking for direct oil exposure or by consuming prey contaminated by oil.
The Bryde’s whales are not endangered, but they are an anomaly in the Gulf of Mexico. There may be less than 30 in the single pod. They are baleen whales and are unusual because they stay in the same general, isolated area of the gulf. There are an estimated 1,665 sperm whales in the gulf, and they often travel long distances. Researchers will track them to determine if they are moving away from oiled waters.
If there is a massive die-off of whales and dolphins in the Gulf of Mexico, this and future research trips will document that, because of the information being gathered today. Reproduction levels may drop, or gradual but persistent changes could occur if their food chain is made toxic.
It will take years of research trips to learn what the BP oil spill will do to these whales and dolphins. “It will have to go on for a long time,” Garrison said.
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