(News-Herald, Panama City)
Gulf World helps investigate unusual dolphin strandings
PAT KELLY / News Herald Writer
2012-03-10 18:12:25
PANAMA CITY BEACH — Dolphins have been showing up dead in record numbers along the northern Gulf of Mexico, and experts are investigating why.
The National Oceanic and Atmospheric Administration issued an Unusual Mortality Event (UME) because of the situation, which has claimed 580 dolphins in higher-than-expected strandings that began in February 2010. The UME was issued in December 2010.
Secret Holmes-Douglas, director of marine mammals at Gulf World Marine Park, says her facility has taken part in the concentrated investigation, which calls for a higher number of biological samples that are then sent off for testing.
Gulf World also has portable X-ray and ultrasound equipment that can be used poolside for rescued dolphins, and it serves as the only long-term marine mammal rehabilitation facility in northern Florida, said Pam George, Gulf World marketing director.
"We always do a necropsy (animal autopsy) on any marine mammal mortality that comes in," Holmes-Douglas said.
Since the UME was issued, "they have asked us to take extra samples" from the internal organs, for instance, as well as skin samples for a history of interactions with fishing equipment, such as scarring from fishing lines or fishhooks.
"The paperwork on the animals is extensive," Holmes-Douglas said.
The numbers
So far along the northern Gulf, five dolphin deaths have been listed as caused by brucellosis, a bacterial infection that can be caused by stress and the suppression of the immune system.
A recording of all unexplained bottlenose dolphin deaths from the Texas/Louisiana border east to Franklin County has continued through this year, with January and February 2012 numbers more than triple the average from 2002-2009.
Holmes-Douglas said her team responded to 14 strandings last year in an area from Walton to Franklin counties. Three have appeared this year in her area, with two mortalities and one animal that was saved and sent to Orlando's SeaWorld, where she is doing well.
Although so far there are no clear ties between the April 23, 2010, Deepwater Horizon oil spill and the high dolphin mortality rate, "severe environmental stress, including from exposure to oil, could have reduced the animals' ability to fight infection," Teri Rowles, coordinator of NOAA's National Marine Mammal Health and Stranding Response Program, said on the NOAA website www.nmfs.noaa.gov.
Blair Mase, NOAA's Southeast Regional Marine Mammal Stranding Coordinator, said this week it was uncertain how long the UME would last because "we are still experiencing a high number of strandings. We are still in the midst of this."
"It is our hope that the number will decrease and we will get back to normal," Mase said.
The brucella bacteria are often found in marine mammals, but humans are rarely infected. Still, Holmes-Douglas said her team routinely uses protection such as face masks, goggles and gloves when handling the stranded dolphins.
Gulf World currently is home to five rough-toothed dolphins that have gone through a rehabilitation process, Holmes-Douglas said, adding that Gulf World marine mammal experts attended a February meeting of the Southeast Regional Stranding Network, where they were briefed on the continuing UME investigation.
Prior UMEs
According to NOAA, there have been 15 UMEs in the Gulf of Mexico since 1991, four of which were specific to manatees. The attributed causes of previous UMEs have been biotoxins, 53 percent; infectious diseases, 7 percent; and unknown causes, 40 percent.
The previous causes are all being considered as possibilities for the current UME, with the Deepwater Horizon oil spill also under investigation for its direct or indirect effect, Mase said.
Mase said the current investigation is being conducted according to strict protocol, where attempts are made to rule out possible causes, including ruling out the oil spill. But, "we are concerned about its possible impact," she said.
The environmental stress of an oil spill can cause a suppression of a dolphin's immune system, leading to bacterial and viral infections. But other "stressers" also have an impact, including algae blooms and climate change, she said.
"Think of your own environment" and what might cause stress, she said. "The Gulf is a structured environment that is affected by many factors: algae blooms, climate change, bacteria, viruses and heavy metals."
George said the Gulf World Marine Institute is part of both the Southeast Marine Mammal Stranding Network and the Sea Turtle Stranding and Salvage Network.
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