Plagues,
Pestilences and Diseases
Hundreds of dead dolphins are washing ashore on the US Gulf
Coast.
By Vivian Kuo, CNN
April 8, 2011 1:56 a.m. EDT
STORY HIGHLIGHTS
* Since February 2010, 406 dolphins have been found dead or
stranded
* Sensitivity about marine life in the area is high after the
BP oil disaster
* Scientists are also concerned about sea turtle strandings
(CNN) -- Dead baby bottlenose dolphins are continuing to wash up
in record numbers on the shores of the Gulf of Mexico, and
scientists do not know why.
Since February 2010 to April 2011, 406 dolphins were found either
stranded or reported dead offshore.
The occurrence has prompted the National Oceanic and Atmospheric
Administration to designate these deaths as an "unusual mortality
event" or UME. The agency defines a UME as a stranding incident
that is unexpected or involves a significant loss of any marine
mammal population.
"This is quite a complex event and requires a lot of analysis,"
said Blair Mase, the agency's marine mammal investigations
coordinator.
Mase said NOAA is working closely with a variety of agencies to
try to figure out not only why the bottlenose dolphins are turning
up in such large quantities but also why the mammals are so young.
"These were mostly very young dolphins, either pre-term, neonatal
or very young and less than 115 centimeters," she said.
Marine mammals are particularly susceptible to harmful algal
blooms, infectious diseases, temperature and environmental
changes, and human impact.
"The Gulf of Mexico is no stranger to unusual mortality events,"
Mase said.
Sensitivity surrounding marine life in the area is particularly
high after the BP oil disaster that sent millions of barrels of
crude into the Gulf of Mexico nearly a year ago.
The incident occurred on April 20, 2010, when a Deepwater Horizon
rig leased to BP exploded, killing 11 workers and leading to the
worst oil spill in U.S. history.
As recently as two weeks ago, scientists documented a dead dolphin
with oil on its remains, Mase said.
Since the start of the oil spill, a total of 15 bottlenose
dolphins have been found with either confirmed or suspected oil on
their carcasses.
Even after the gushing well was capped, the agency said nine oiled
dolphins have been found since November 2, 2010.
Of those nine, six were confirmed to contain oil from the
incident; one was found with oil that did not match the Deepwater
Horizon samples, and two have not yet been tested.
The dolphin deaths may be completely independent from the oil
spill, Mase said.
"Even though they have oil on them, it may not be the cause of
death," she said. "We want to look at the gamut of all the
possibilities."
The agency said bottlenose dolphins are actually the
most-frequently found stranding marine mammal.
Scientists say they are equally concerned about the number of sea
turtle strandings.
Similar to the dolphin deaths, an abnormally high number of
turtles have been found either floating close to shore or washed
up on shores in Louisiana, Mississippi and Alabama.
"The vast majority of these are dead, with states in moderate to
severe decomposition," said Barbara Schroeder, NOAA Fisheries
national sea turtle coordinator.
The majority of them are Kemp's ridley sea turtles, an endangered
species since 1970. But some strandings included loggerheads,
which are also endangered.
"Since January 1st, we've had just under 100 strandings,"
Schroeder said. "About 87 of those have been documented since the
middle of March."
Only about a third of those found were in good enough shape to
perform necropsies, she said. Seven turtles showed indications
that they had been in accidents involving watercrafts, while
another displayed injuries consistent with being caught on a hook.
Results from the rest appeared to indicate they had drowned near
the bottom of the Gulf -- possibly either from forced submergence
or an acute toxic event.
NOAA Fisheries Stranding Program Coordinator Dr. Teri Rowles said
tissue samples from both turtles and dolphins are being carefully
documented due to the civil and criminal litigation ongoing with
BP.
"We are looking at what is the impact of the oil spill and the
response activities to the oil spill event, and what impact they
had on the Gulf of Mexico ecosystem," she said. "We did not say
that the dolphins have died because of the oil, just that they
have come back with oil on them."