Melon-headed whale likely died of parasitesMarch 8th, 2013 in Biology / Plants & Animals
Dr Tom deMaar, senior veterinarian at the Gladys Porter Zoo in Brownsville, checks vital signs of a melon-headed whale supported by volunteers at the UTPA Coastal Studies Lab on South Padre Island. Credit: Tony Reisinger
Pushing beached marine mammals back out to sea can pose health risks to humans, violates federal law and can actually do the animal more harm than good, according to marine experts who took part in a recent effort to save a distressed whale at South Padre Island.
"Despite the heroic efforts of so many people, we were unable to rehabilitate a beached melon-headed whale that washed ashore on Feb. 25," said Tony Reisinger, the Texas A&M AgriLife Extension Service agent for coastal and marine resources in San Benito.
"Its health eventually deteriorated to a point that it was untreatable. It was in lots of pain and had to be euthanized three days later."
But the event serves as a learning tool for future strandings, he said.
"The first lesson is that people who find beached mammals should know that these mammals are federally protected. People should immediately call the police or other authorities," Reisinger said. "That's what happened in this case and trained first responders were on hand quickly to start the proper rehabilitation."
Among those who assisted in the subsequent efforts to save the whale was the Texas Marine Mammal Stranding Network, a nonprofit organization based in Galveston.
Heidi Whitehead, the network's executive director, said beached mammals are there for a reason that must be determined by experts.
"Pushing such animals back out to sea are well-intentioned efforts, but whatever pathogens that caused the mammal to become stranded could pose a danger to humans," she said. "Animals pushed back out to sea are usually beached again a short time later, so it just delays the time that we can get to them to make a proper assessment. It could also cause them to aspirate water."
Whitehead said the goal of her organization is to eventually send rehabilitated mammals back out to sea.
"Hopefully we can help them, but if they can't be rehabilitated, we can at least spare them a painful death. The public should also be aware that since all marine mammals are federally protected, only authorized individuals and organizations are permitted to handle them."
A post-mortem evaluation, known as necropsy, was performed in Galveston shortly after the almost 8-foot long whale expired in late February. While test results could take several months, Whitehead said most such beached species usually succumb to parasites.
"Melon-headed whales are the third most commonly stranded sea mammals on the Texas coast, behind the Bottlenose dolphin and the Pigmy sperm whale," she said. "Based on the history of these events, most suffer from brain lesions or parasites they acquire from the fish they eat. The parasites make their way to the brain and near the ear bones. We believe that this could have been the final straw in bringing this animal to the beach."
First responders used a specially designed stretcher to move the deep-water whale to a tank at the University of Texas Pan American's Coastal Studies Lab where it was kept afloat around the clock by volunteers, and treated by Dr. Tom deMaar, a veterinarian at the Gladys Porter Zoo in Brownsville.
"That led to another lesson we learned in this event," Reisinger said. "We need more coastal naturalists trained in marine mammal strandings. To keep this whale afloat and alive with its blowhole above water required a minimum of two volunteers in the tank wearing appropriate protective gear working two- to three-hour shifts, 24 hours per day, pushing the whale around the tank.
"It was very stressful making sure we had enough people lined up ready to work. That entire event was coordinated by Brigette Goza, an employee at the coastal lab who went for far too long without sleep. Leslie Sweeten, a wildlife volunteer at the lab, provided lots of relief."
There are some 98 Texas Coastal Naturalists in South Texas, but not all are trained in marine mammal stranding response. More will be trained in a new class to start March 30.
"We also learned that we need a larger tank. The one we used is 16 feet in diameter, but it's obvious we need a larger tank. Efforts are under way now to start a fund drive for that."
Texas records an average of one beached melon-headed whale per year, Reisinger said. According to network records, this was the fourth of its species to wash ashore at South Padre Island since 1996.
"The prior such stranding happened in 2007 and it didn't survive either," he said. "Keeping distressed marine mammals alive, whether it's cold-stunned sea turtles during a freeze or ill whales like this one, is very stressful on everybody concerned. It takes a tremendous amount of work, lots of skill, lots of scheduling and a great deal of sacrifice by a lot of people, mostly volunteers."
But there are successes, he said, including the rescue of a beached Bottlenose dolphin several years ago.
"That one beached shortly after it was born. His rehabilitation was successful. We named him Gilly, and he now lives at SeaWorld in San Antonio. Once you start feeding such an animal at such an early age, it's difficult to release it into the wild.
"And in early 2011, volunteers saved over 1,000 sea turtles stunned by a cold snap, which also required heroic around the clock efforts."
This latest beached whale showed obvious signs of distress, Reisinger said.
"These melon-headed whales are in the dolphin family, along with Bottlenose dolphins," he said. "They are often called blackfish. They are very social animals and live in pods that can have as many as 300 to 1,000 whales. They can live up to 30 years, but based on tooth wear, I'd estimate this one to be about 7 years old. It was 7-feet, 8-inches long, but they usually grow up to 9 feet.
"It had lots of cookie-cutter shark bite scars and a fresh bite on its left side. It had great difficulty moving its fluke and staying upright in the water. That lack of balance was likely an inner ear disorder probably caused by parasites that affected its balance. It's sad to see such a magnificent animal in distress."
Their warm skin, especially in cold water, brings on a peculiar realization, Reisinger said.
"When you feel their warmth, you realize they are mammals like we are. They are not cold fish. That's why I'm so appreciative of all the volunteers and organizations who helped in this effort. South Texas is lucky to have the UT-Pan Am Coastal Studies Lab, under the direction of Dr. Tom Whelan.
"We also owe a huge debt of gratitude to Dr. deMaar, whose dedication and expertise is extraordinary. The Texas Marine Mammal Stranding Network of Galveston provided great support throughout, as well as their chapter from Corpus Christi."
Provided by Texas A&M University
"Melon-headed whale likely died of parasites." March 8th, 2013. http://phys.org/news/2013-03-melon-headed-whale-died-parasites.html