was not a pretty sight for David Mickey and Sue Dayton the fall day
they came upon a large dark object on the Ocracoke beach. Walking
closer, they identified what they had spotted as a dead bottlenose
they called the Marine Mammal Stranding coordinator for North
Carolina’s central coast, Vicky Thayer. She came to the island and,
with Mickey’s assistance, performed a necropsy on the animal. Mickey
and Dayton had just moved to Ocracoke and this was their introduction
to the series of dolphin strandings in mid-Atlantic waters last year.
Over the next couple months, two more dolphins would be found stranded on the island.
to Thayer, the number of strandings varies from year to year, but there
has been an increase of bottlenose dolphin deaths from July 2013 to
June 2014 in North Carolina, due in part to a virus known as dolphin
moribillivirus. Of the three dolphins that were stranded on Ocracoke
Island last winter, one tested negative for morbillivirus and results
from the others are not completed.
deaths were part of the largest number of strandings of bottlenose
dolphins and small whales ever recorded on the East Coast, said William
McLellan, state stranding coordinator at the University of North
Carolina Wilmington. A similar morbillivirus outbreak took place in
1987-‘88, killing up to half the bottlenose dolphin population in the
mid-Atlantic during an eight-month period.
Mickey and Dayton helped arrange for Keith Rittmaster, the natural
science curator at the North Carolina Maritime Museum in Beaufort, to
visit Ocracoke and give a presentation on his work with whales and
dolphins. Rittmaster has been involved with many strandings, also known
as beachings, that have occurred here over the years.
in fishing line, nets and anchors; ingestion of trash, including life
jackets and milk jugs; injuries from propeller blades on boats and
ships; shark attacks and sting ray barbs; and viruses, bacteria and
parasites are among the causes of death in marine mammal strandings
described by Rittmaster. He accompanied the descriptions with slide
depictions of the many beached whales and dolphins he has studied.
dolphins and porpoises, known collectively by scientists as
“cetaceans,” have intrigued humans for centuries, as evidenced by the
nearly full house Rittmaster’s presentation attracted. North Carolina’s
coastal waters are home to at least 33 species of marine mammals, and,
of the 10 “great” whales that exist, eight have been documented
offshore here, according to N.C. Aquariums.
are toothed whales, known by the scientific name odontoceti, of which
the sperm whale is the largest. There are also baleen whales, or
mysticeti, including humpback, blue, North Atlantic right, fin, sei and
minke whales. Baleen whales are so called because instead of having
teeth, they have racks of baleen — hanging sheets of fringed keratin
that filter and trap small fish, shrimp, and krill.
species of pilot whales, several species of dolphin and one type of
porpoise swim off North Carolina’s shores, of which bottlenose dolphins
are the most frequently seen. Harbor porpoises and Atlantic spotted
dolphins are also abundant.
factors play a role in the great diversity of marine mammals off our
coast, explained Rittmaster. Warm water of the Gulf Stream, coming from
the south, mixes with the colder water of the Labrador Current,
streaming from the north, near the N.C. coast. It is also where the
inner and outer continental shelves meet, with the same result.
Carolina’s coastal native people probably took advantage of the beached
whales that washed ashore, using their meat and blubber. It was not
until the Europeans arrived that the animals were hunted for their
blubber that was boiled to extract its oil. This brought several
species to the brink of extinction. Oil from the sperm whale was used
for lubrication, that from the humpback for lighting and oil from the
lower jaw of dolphins for lubrication of fine machinery and watches.
cetaceans are protected by the federal Marine Mammal Protection Act and
the International Whaling Commission. The most endangered species, the
North Atlantic right whale (called so because, in former times, it was
the “right” whale to hunt) appears to be making a slight comeback. This
winter 14 right whale calves were born off the Southeast, a number that
relieved conservationists who feared there would be fewer.
The National Oceanic and Atmospheric Administration recently
proposed expanding the designated critical habitat for the endangered
right whales, including a portion of the southern N.C. coast where they
have calves and nurse. Overall, the rule would expand their critical
habitat to almost 30,000 square nautical miles.
are worried about the Navy’s sonar testing off the N.C. coast, which
they think can adversely affect cetaceans. Thirty-four whales of three
different species were stranded and died along the Outer Banks in
January 2005 following offshore Naval testing using sonar. While there
was no definitive proof that the tests caused the beachings, they were,
according to McLellan, “investigated as an acoustic event, and it could
not be ruled in or out.” Sonar tests are also, he added, “levels of
harassment,” that may contribute to aberrant cetacean behavior.
There are many reason why marine mammals beach themselves, Thayer explained.
want a simple answer, but it’s not that easy,” she said. “It’s very
difficult to determine cause of death and there have not been many
cases worldwide that have been definitively attributed to acoustic
trauma. Numerous factors can combine to cause marine mammal strandings,
although the burden of proof should be on the group causing the
Reynolds, senior attorney for the Natural Resources Defense Council,
thinks differently. “There is no question that sonar injures and kills
whales and dolphins,” he said in 2008. According to the defense
council, sonar can cause bleeding around the brain, ears and other
tissues and large bubbles in organs, similar to the bends, which
sometimes kills divers who surface too quickly.
magazine, Scientific America, writes that sonar sound waves travel
hundreds of miles under water and retain intensity of 140 decibels 300
miles from their source. “Evidence shows that whales will swim hundreds
of miles, rapidly change their depth, sometimes leading to bleeding
from ears and eyes, and beach themselves to get away from the sounds of
sonar,” notes an excerpt.
air guns, which cause similar effects as sonar, are proposed to be used
off the N.C. coast, starting this year, to search for potential
reservoirs of oil and natural gas. McLellan says that seismic
exploration along North Carolina’s coast was conducted last by the
National Science Foundation and the Lamont-Doherty Earth Observatory at
Columbia University to look at the ocean floor and channels and study
says that efforts are made to insure that cetaceans are beyond a
tolerable radius of seismic air gun use, a radius in which air guns are
assumed to have the potential of altering cetaceans’ health or natural
behavior. But, she explains, marine acoustics and its relation to
cetaceans is complex. Beyond having direct physical effects on
cetaceans or their behavior, seismic exploration and related activities
— boat use, leaks, spills — may have indirect effects by affecting
cetaceans’ ability to find and capture food, hear approaching predators
and find mates.
Federal Bureau of Ocean Energy Management approved opening an area of
the Atlantic Coast from Delaware to Florida for the seismic blasts,
saying if precautions are followed, then the seismic exploration
“should not cause any deaths or injuries to the hearing of marine
mammals or sea turtles.” The N.C. Division of Coastal Management is
currently evaluating three permits for such testing.
federal scientists, are worried about what such extreme pulses of sound
can do. “It’s been pretty well documented that seismic surveys have
disrupted animal behavior and animal communication,” said Danielle
Cholewiak, a senior acoustics researcher for the National Oceanic and Atmospheric Administration.
Weiss Taylor, who leads the Outer Banks Center for Dolphin Research,
said, “There is a likely chance they (dolphins) would be affected by
the seismic testing.”
environmental group Oceana says the seismic blasts threaten to injure
or kill thousands of Atlantic marine mammals, and even pose a threat to
the area’s fisheries.
American Petroleum Institute maintains that the seismic blasts are
safe: “Operators already take great care to protect wildlife, and the
best science and decades of experience prove that there is no danger to
marine mammal populations.”
federal environmental impact statement released in February stated that
most effects to sea life would be “negligible or minor, and no major
impacts were identified.”
to Doug Nowacek, associate professor of conservation technology at the
Duke University’s marine lab in Beaufort, air gun blasts may be heard
underwater over distances of more than 2,000 miles. “If there’s a
survey in Virginia, under conducive sound travel conditions, you’re
going to hear it in southern North Carolina easily.”
says there has been far too little data collected on the effects of the
seismic air guns, and he is cautious of industry assertions that air
guns are harmless.
and dolphins are beloved and iconic symbols of the world’s oceans.
Understanding what causes them to strand and die is not easy, in spite
of the work being done by Rittmaster, Thayer, McLellan and others.
Preventing anthropogenic cetacean deaths should, however, be a high
priority for everyone. A sustained prompt response to strandings is
needed to better understand the various impacts that influence their
What to do if you see a stranded marine animal
The Marine Mammal Center recommends these steps if you come across a beached seal, whale or dolphin:
touch, pick up, pour water on or feed the animal. They are wild
animals and can bite. They also are easily stressed by humans.
return the animal to the water. Seals temporarily “haul-out” on land to
rest. Harbor seal mothers often leave their pups ashore while they’re
feeding at sea. A beached whale, dolphin or porpoise should be reported
- Observe the animal from a distance of at least 50 feet. Keep people and dogs away.
physical characteristics such as size, presence of external earflaps
and fur color. This helps us determine the species, what rescue
equipment and volunteers are needed.
- Note the animal’s condition. Is it weak and underweight? Are there any open wounds?
- Does the animal have any obvious identification tags or markings?
- Determine the exact location of the animal in order to provide accurate directions to rescuers.
The National Oceanic and Atmospheric Administration recommends calling these numbers if you come across a stranded marine mammal or sea turtle:
- Cape Hatteras National Seashore, Avon, 252-216-6892
- N.C. Sea Turtle Stranding and Salvage Network hotline, 252-241-7367
- N.C. Division of Marine Fisheries, Morehead City, 252-241-5119
- N.C. Maritime Museum, Beaufort, 252-504-2452
- OBX Marine Mammal Stranding Network, Outer Banks, 252-455-9654
- University of North Carolina Wilmington, Marine Mammal Stranding Program, 910-254-5713
article is provided by Coastal Review Online, an online news service
covering North Carolina's coast. For more news, features, and
information about the coast, go to www.coastalreview.org.)