The bottlenose dolphin known as “Y-18” lay quietly on a gray cushion mat on the floor of the RV Megamouth as a team of scientists raced through a series of tests aimed at determining whether chemicals associated with the oil from the BP Deepwater Horizon spill have affected its health.
With veterinarian Forrest Townsend keeping watch on the team’s progress, and the dolphin’s vital signs, during the speedy medical examination Monday morning, researchers drew blood, samples of blubber, urine and feces, checked the dolphin’s teeth, and used a mobile ultrasound machine to map its inner organs.
As the work proceeded beneath the aluminum boat’s Bimini umbrella, several of the researchers poured water on Y-18’s skin to keep it from drying out, as the temperature quickly reached 85 degrees on the water between Dutch Island and Grand Isle.
After 10 minutes, though, both the animal’s labored breathing — a series of whooshes through the blowhole — and the electrocardiogram machine attached by leads to Y-18’s skin showed it was becoming stressed, and the 573-pound dolphin was eased back into the water.
There, the final steps of the exam were completed — branding irons dipped in liquid nitrogen were held onto the dorsal skin, marking the dolphin with its scientific name forever.
A tag containing a radio beacon and a satellite transmitter also was attached to the fin atop its back.
Then the scientists released the dolphin, and it swam quickly west toward Caminada Bay.
Dozens of research projects are in progress
Left behind were dozens of vials and packets that scientists hope will help federal and state officials determine the damage caused to dolphins and other natural resources by the oil spill.
The dolphin research is just one of dozens of such research projects for the Natural Resource Damage Assessment process required under the Oil Spill Act of 1990. The law requires BP and other companies found responsible for the spill to pay for projects that would mitigate the harmful effects caused by the oil or compensate the public for the loss of the resources.
Other studies are focused on effects on birds, deepwater corals, sperm whales, Atlantic bluefin tuna and other fish species, and both submerged aquatic vegetation and wetlands, including potential erosion, said Tom Brosnan, an environmental scientist who directs NOAA’s Office of Response and Restoration, which oversees the damage assessment process.
A key question researchers are trying to answer is whether oil that washed into the Barataria Basin in the months after the April 2010 spill may be to blame for the strandings of 85 premature, stillborn or neonatal bottlenose dolphins that occurred between January and June, said Teri Rowles, director of NOAA’s Marine Mammal Health and Stranding Response Program.
In addition, a dead adult dolphin found in June in the bay tested positive for oil from BP’s well on its skin, she said. A second dolphin carcass found in July also was stained with oil, but the results of tests to determine its source are not yet complete, she said.
The scientists will be testing many of the samples for polycyclic aromatic hydrocarbons, a chemical component of oil that is believed to cause birth defects and could be linked to the baby dolphin deaths.
Determining a link is complicated by the fact that a percentage of dolphin pregnancies normally end in stillbirth or abortion, Brosnan said.
The scientists have tested 30 dolphins near Grand Isle since Aug. 3.
Sarasota dolphins are the control group
The results of those tests will be compared to a similar study of bottlenose dolphins near Sarasota, Fla., which is part of a 40-year research program run by Randall Wells, a marine biologist for the Chicago Zoological Society and the Mote Marine Laboratory. The Sarasota dolphins are being used as a control group, bcecause they are not believed to have been exposed to BP oil.
The death of dolphins in Barataria Bay actually predates the BP spill. Between Feb. 1 and Apr. 29, 2010, before oil entered the bay, 113 cetaceans — the term used for members of the whale family, including dolphins — were stranded in the area.
Between Apr. 30 and Nov. 2, NOAA received reports of 115 cetaceans stranded or reported dead offshore, while between Nov. 3 and Aug. 7 of this year, another 284 were stranded, including the stillborn and aborted babies.
The strandings before the spill may have been caused by toxic algae blooms or other causes, Rowles said.
The dolphin tests were being observed by officials with environmental agencies in Louisiana and Mississippi, who are considered trustees for the public natural resources under the Oil Spill Act, and a representative of BP.
Researchers were required to obtain a permit under the Marine Mammal Protection Act to conduct the examinations.
Dolphins were captured with a seine net that was pulled slowly toward shore by about a dozen scientists standing in 4 feet of water.
On Monday, one dolphin jumped over the net, eluding capture. An ultrasound inspection of a female dolphin found that she was pregnant and the researchers conducted abbreviated tests on her in the water.