strandings of only one animal, can occur for a number of reasons.
Dolphins, whales, porpoises, and seals may strand alone when the animal
becomes lost or disoriented or is suffering from an illness, infection
or injury. Newly weaned animals sometimes have a hard time thriving on
their own and may strand as a result of their own inexperience. Older
animals may also die of natural causes. Unfortunately, our actions as
humans can often affect marine mammals. Some animals strand and/or die
as a result of Human Interaction. The detrimental interactions include
entanglement if fishing gear and marine debris, being struck by ships,
being shot, and even being harassed by well-meaning beachgoers.
The phenomenon of mass
strandings affects only cetaceans (dolphins and whales, infrequently
porpises). Mass strandings occur when two or more of these animals
strand (excluding a mom/calf pair) within the same general geographic
region and within the same tidal cycle. There are usually multiple
factors that play a role in causing these events. The one constant
thread among all mass strandings is that like humans, the species of
whales and dolphins involved are highly social animals that depend upon
the safety and resources of the group in order to survive. This group
mentality that is so helpful to these animals at sea can unfortunately
cause otherwise healthy animals to strand en masse when they are near
shore. When one animal enters shallow water or strands, the entire group
Other factors that may
contribute to a mass stranding include predator evasion, complex
topography, tidal fluxes, extreme weather, geomagnetic anomalies, and
sonar or other acoustic disturbances. Mass strandings of whales and
dolphins have occurred on Cape Cod for hundreds of years, thus it is
unlikely that the events in this region are the result of modern human
In most stranding cases,
the cause of stranding is unknown, but some identified causes include:
harmful algal blooms
injuries due to ship
In addition, strandings
often occur after unusual weather or oceanographic events.
Social structure: The species of cetaceans (dolphins and whales) that typically
mass strand are often pelagic (offshore) animals that form tight social
groups. Unfortunately, the very social bond that serves them so well at
sea may be the cause of their downfall as they come close to shore.
These animals stick together at all times, so if one animal becomes
sick, injured or disoriented, the entire group may strand instead of
just the one affected dolphin or whale.
Predators: Scientists and researchers believe that threats by predators
such as sharks and orcas may cause marine mammals to swim closer to
shore where they are at increased risk of stranding.
topography: Animals come near shore at different times of the year and may
become disoriented and trapped by complex inlets and the hook-like shape
of areas such as Cape Cod, Massachusetts. Wellfleet Bay is an additional
hook of land within Cape Cod Bay, and this added level of topographic
complexity is likely the reason that 60% of all mass strandings in this
area have taken place in Wellfleet. Researchers have also found
similarities in the substrates of areas around the world with a high
propensity for mass strandings: these locations tend to have gently
sloping sandy or muddy flats that may inhibit the animals’ ability to
fluxes: Mass strandings often coincide with full and new moon tidal
cycles. The extreme high and low tides during full moons allow animals
to swim farther inshore than normal, leaving them high and dry when the
tide turns. The tides in Wellfleet Harbor can fluctuate up to 12
vertical feet (high tide to low tide) during a full moon cycle.
Extreme weather: High winds and stormy seas can cause a storm surge, allowing
animals to go farther inshore than usual, making them more likely to
become stuck when the tide recedes. It is also thought that these
conditions may increase the likelihood that animals become disoriented
in complex coastal areas.
Sonar and other
acoustic disturbances: Since many dolphins and whales rely on sound for navigation,
underwater acoustic disturbances from oil exploration, military sonar or
other sources may cause disorientation that could result in a stranding.
Strandings Around The World
2011 New Zealand Department of Conservation
New Zealand conservation
officials have euthanized the last surviving pilot whales from a pod of 65
that stranded on a remote South Island beach.
Department of Conservation
Golden Bay Area Manager John Mason said 16 whales had died since yesterday
morning and DOC staff had taken the difficult decision this morning to
euthanize the remaining 18 whales to end their suffering.
'We had wanted to give the
whales a chance to refloat and hopefully find their way out to sea in the
high tides yesterday and overnight. But they re-stranded each time and
more whales died.
'The whales seem to have
come in a little further inshore in each re-stranding. The tides are
reducing so it became very unlikely the remaining whales would get out to
sea and that they would survive.
"Rather than prolong
the whales' suffering we decided to take the humane course of euthanizing
the remaining 18 whales this morning.'
The stranded pilot whales
were reported to DOC staff on Monday evening by a Farewell Spit tour
guide. DOC rangers who went to the area found 20 dead whales and one whale
in a poor condition was euthanized. The next morning the rangers found
another 44 whales stranded nearby, 2 - 3 kilometers from shore, 34 of
which were alive and 10 dead.
A rescue of the whales was
too dangerous to undertake given the distance of the whales from shore in
a remote location where tides come in rapidly over the shallow tidal
flats. It would be arduous and unsafe for people to walk the 2 - 3
kilometers back to shore after refloating the whales in chest-deep water.
DOC rangers remained at the
Spit yesterday and overnight to monitor the whales. They found another 10
whales had died late yesterday afternoon when the high tide receded. A
further six whales were found dead when rangers checked again at first
light this morning.
Whales die in stranding
13, 2011-16 sperm whales died yesterday, leaving another four of the
ocean giants struggling for survival overnight.
The deaths occurred after
20 whales became stranded at Ocean Beach, near Strahan, on the West Coast,
late in the morning.
Only four survived despite
the rescue efforts of West Coast Parks and Wildlife Service personnel.
Late last night, another
eight sperm whales were being monitored in nearby Macquarie Harbour. Four
of them were stranded on sandbars.
Marine experts consider
Ocean Beach and Macquarie Harbour to be among Australia's main hot spots
for whale strandings.
PWS West Coast parks and
reserves manager Chris Arthur said it was not known why so many strandings
occurred at the locations.
"We don't know why,
but there are several locations in the world where whale strandings occur
frequently and Ocean Beach is one of them," Mr Arthur told the Sunday
Nov 2010 Whale deaths in Donegal: pod stranded
on Rutland beach
SCIENTISTS HAVE taken
skin and tissue samples from some of the 33 long-finned pilot whales
which died after a mass stranding off Donegal.
The carcasses of the 33
mammals were discovered early on Saturday on the back strand of Rutland
Island between Burtonport and Arranmore island.
NOAA steps up probe of 146
New England seal deaths
November 5 , 2011 NOAA At
least 146 dead seals have been documented from September 1, 2011 to
November 3, 2011, most of which were harbor seals (120), including 19
females, 28 males, and 99 animals of unknown sex. The majority of cases
have involved young of the year and many have similar skin lesions
(ulcerative dermatitis). Unlike historical young of the year harbor seal
mortalities, which are often attributed to malnutrition, many of these
animals are in good body condition. The highest number of strandings
occurred during the week of September 25 (42 harbor seals). The
146 seals generally were less than a year old and had healthy appearances.
They were found in Maine, New Hampshire and northern Massachusetts.
Stranding records for the
northeast region over the preceding four years show an average of 31
harbor seal strandings for the month of September and 24 harbor seal
strandings for the month of October. Thus, the 2011 strandings that
involved 61 seals in September and 46 seals from October 1-21 are above
the expected average.
30 whales stranded on
Tasmanian South Bruny Island beach
17, 2011-A POD of about 30 pilot whales has stranded on Tasmania's
South Bruny Island.
The whales are believed to
be pilot whales and became stranded late this afternoon.
Department of Parks and
Wildlife spokeswoman Liz Wren said about 12 of the whales were still alive
and Parks and Wildlife are on the beach trying to help the stranded
28 whales die in New
Feb 15, 2010 WELLINGTON New
Zealand Twenty-eight pilot whales have died after they became stranded on
a remote beach in the far south of New Zealand, conservation officials
told local media .
The whales came ashore at
West Ruggedy Beach in the northeast of Stewart Island, Department of
Conservation (DOC) manager Mark Townsend told the Southland Times.
The whales were found by a
hiker on Sunday morning. The DOC staff arrived about an hour later but
were unable to save any of them.
The conservation officials
found nine whales already dead and there was no alternative to killing the
Unprecedented mass whale
New Zealand Sep 22,
2010 -Department of Conservation staff are calling a mass pilot
whale stranding at Spirits Bay in Northland "unprecedented".
Seventy-four whales are
stranded across two kilometres on the remote beach north of Kaitaia.
So far nine have been
successfully refloated. There are up to 50 whales just off-shore.
Whales die after stranding
on Senegal coast At least 38 died after dozens showed up on shore
DAKAR, Senegal — The
bodies of at least 38 whales have washed up on a Dakar beach and wildlife
officials say as many as 100 swam up close to the shore.
Villagers living nearby
said the whales were spotted late Tuesday night, veering closer and closer
to the coast as the tide came in. By Wednesday morning many were beached.
States Marine Mammal Unusual Mortality Events
Northern Gulf of
Florida (St. Johns
Atlantic while-sided dolphins
Guadaloupe fur seals
Texas and Louisiana
(manatees and bottlenose dolphins)
Florida (west coast)
Harbor seals and
Florida (west coast)
(primarily humpback whales)
Gulf of Maine
Florida (west coast)
dolphins, California sea lion, sea otters)
Hawaiian monk seals
California sea lions
California sea lions
Florida (west coast)
California sea lions
October 2011-Under the
Marine Mammal Protection Act of 1972 (as amended), an Unusual Mortality
Event (UME) has been declared for cetaceans (whales and dolphins) in the
northern Gulf of Mexico (Texas/Louisiana border through Franklin County,
FL) from February 2010 through the present.
Note: These numbers are
preliminary and may be subject to change. As of November 13, 2011, the UME
involves 594 Cetacean "strandings" in the Northern Gulf of
Mexico (5% stranded alive and 95% stranded dead). Of these:
stranded cetaceans (dolphins and whales) from Franklin County, FL to the Texas/
NOTE: Historical data from 2002-2009 excludes 2 previous UMEs in the panhandle
of Florida (March-April, 2004 and Sept. 2005-April 2006). Historical data from
2008 through present are unvalidated and numbers may be subject to change as
more information becomes available. Data include any strandings reported on or
before November 13, 2011 and include 6 cases that were incidental scientific
data collection takes and 1 take incidental to trawl relocation for a dredging
project. Data from 2010 and 2011 are considered preliminary and may be subject
to change as more information becomes available.
An increased number of
bottlenose dolphins (Tursiops truncatus) stranded along the Texas
coastline in February and March of 2008. The February strandings were
spread out along the entire Texas coast, although Brazoria, Galveston and
Nueces counties saw the most increase. On March 3rd, 21 dolphins washed
ashore in Galveston and Jefferson counties in late stages of
decomposition. Most animals showed evidence of severe scavenging from
shark bites with only a partial carcass present. The dolphin strandings
continued to occur in high numbers throughout March 2008.
The high numbers of
strandings in March were limited to Matagorda, Brazoria, Galveston, and
Jefferson counties with very few strandings (5 total) occurring along
other areas of the Texas coastline. The total number of strandings
recovered by the Texas Marine Mammal Stranding Network (TMMSN) in March
was 78. In April, bottlenose dolphin strandings have decreased
significantly with the total of 119 from February 1.
Mid-Atlantic Small Cetacean Unusual Mortality Event
increasing number of small cetaceans have stranded along the Mid-Atlantic. An
elevated number of common dolphin, Delphinus delphis (27), and Atlantic
white-sided dolphin, Lagenorhynchus acutus (5), mortalities occurred from New
Jersey to North Carolina from January 1 to April 15, 2008. The 24 of the 32
strandings were in February and March, with 17 occurring in Virginia. Several
animals have stranded on the Outer Banks, NC where access is difficult or
limited. Approximately one-third of the animals have stranded alive and most of
the remaining animals have been fresh dead to moderately decomposed.
Friday, April 28, 2006-Washington
-- Federal marine specialists have concluded that Navy sonar was the most likely
cause of the unusual stranding of melon-headed whales in a Hawaiian bay in 2004.
Credit:FAO Fisheries Global Information System
The appearance of as many as 200
of the normally deep-diving whales in Hanalei Bay in Kauai occurred while a
major American-Japanese sonar training exercise was taking place at the nearby
Pacific Missile Range Facility.
The report is the latest in a
series of scientific reviews linking traditional mid-frequency naval sonar to
whale strandings. The sonar has been used for decades, but it was only recently
the apparent connection to strandings was established.
While the National Oceanic and
Atmospheric Administration scientists said they could not definitely state that
sonar caused the strandings, they said extensive study led them to the
conclusion that there was no other likely cause.
The Navy says it was virtually
impossible for its sonar to have led to the Hanalei Bay stranding.
The Navy is planning another
major sonar testing maneuver in the same area in July and -- for the first time
-- NOAA has formally asked the Navy to use expanded measures to protect whales
from the possible effects of its sonar.
The active sonar used by
navies around the world sends out loud pings of sound that appear to frighten
and disorient whales, especially deep-diving species like melon-headed whales.
on day of sub mission
BY JENNIFER BABSON The Miami
Tue, Mar. 08, 2005 KEY
WEST - A nuclear-powered
submarine used two different types of active sonar to navigate over several days
as it trained off the Florida Keys last week, including the day of a massive
dolphin stranding in Marathon, the U.S. Navy said late Monday.
At the time, the submarine was
approximately 39 nautical miles southwest of Marathon, where about 80
rough-toothed dolphins -- nearly 30 of which have since died -- beached suddenly
The submarine, the
Connecticut-based USS Philadelphia, was in the Keys for about 10 days, the Navy
Philadelphia (SSN 690)
A Navy spokeswoman said it was
premature to speculate on the cause of the strandings and whether the incident
had anything to do with sonar use. Necropsies and tests are underway on the dead
animals by fisheries biologists from the National Oceanic and Atmospheric
Administration. That process could take months to complete.
''The cause is not known and I
cannot speculate, but every effort will be taken between federal agencies to
determine what might have caused the stranding,'' said Lt. Cmdr. Jensin Sommer,
spokeswoman for Naval Submarine Forces, based in Virginia.
Some scientific reports say there
is evidence that marine mammals may have a particular sensitivity to active
sonar. The technology allows subs and ships to spot targets and other vessels by
emitting sound waves that bounce off objects, revealing distance and location.
Marine mammals rely on sound for
just about everything, from feeding to finding a mate to communicating, which
different animals do at different frequencies.
Dolphin and whale strandings,
however, are not unusual in Florida and can stem from a variety of
circumstances, from a sick dolphin leading a pod onto shore to harmful algae
SUB'S SONAR USE
After it surfaced last Monday,
the Philadelphia used mid-frequency active sonar on its bow in reduced
visibility to ''provide for the submarine's ability to avoid potential contact
with other vessels at sea'' for a period of 21 minutes, Sommer said.
On three other days, Feb. 27,
March 1 and March 2 -- the day the normally deep-water dolphins mysteriously
beached on offshore flats -- the sub used high-frequency active sonar mounted on
its sail while it was submerged to help it ''avoid other ships'' before it came
to the surface, Sommer said. She did not know how long the high-frequency sonar
was used, but said it was ''short duration'' and of low intensity.
High-frequency sonar is
considered to have a shorter range than medium frequency or low frequency.
Factors like water temperature and salinity can also affect how far the sound
After a whale stranding in 2000
in the Bahamas, the Navy acknowledged in a report the existence of some marine
mammal sensitivity to sonars, but has also argued at times that the extent of
any cause-and-effect is scientifically vague.
The Natural Resources Defense
Council, an environmental group, successfully sued the military in 2002 to limit
use of new, low-frequency sonar believed by some to be particularly damaging
because of its ability to travel extremely long distances. Some types of sonar
can be extremely loud -- as much as 235 decibels at close quarters, equivalent
to the noise made by a Saturn V rocket on takeoff -- according to the council.
''It's too early to draw a
conclusion, but the Navy's use of active sonar near the stranding site heightens
our concern that sonar played a role in harming these animals. We already know
that exposure to high-intensity sonar can kill marine mammals. A full
transparent investigation is needed to get to the bottom of it,'' said Joel
Reynolds, director of the council's Marine Mammal Protection Project.
Within the past two months, at
least 35 whales of three species stranded off the Outer Banks of North Carolina.
The stranding coincided with Navy sonar exercises in the area, though a final
cause of death for the animals hasn't been determined.
In recent years, military sonar
use has also been alleged as a factor in the strandings of porpoises off the
coast of Washington state, and of melon-headed whales off the coast of Hawaii,
while other potentially sonar-related strandings have occurred in Greece and the
The International Whaling
Commission last year issued a report supporting a link between active sonar use
and whale deaths.
Some researchers believe that
sonars may disorient or scare marine mammals, causing them to surface too
quickly and creating the equivalent of what divers know as the bends -- when
nitrogen is formed in tissue by sudden decompression, leading to hemorrhaging.
A POSSIBLE CLUE
In South Florida, biologists are
hoping that necropsies of the dolphins who died after the stranding may shed
some light on what prompted the incident. One key clue may be the condition of
the animals' acoustic tissue, a potential indicator of sonar damage.
''As with every marine mammal
stranding, we are conducting a thorough investigation,'' said Laura Engleby, a
biologist for NOAA Fisheries, which coordinated a massive response to the
stranding last week and is now spearheading efforts to determine its cause.
``It's way too early for us to
know what caused this, and our scientists are collecting as much data as
Eleven dead animals were examined
and their tissue sampled over the weekend, with more scheduled for necropsy
later this week.
At least 20 of the dolphins
managed to make it out to sea within a day of the incident.
But at least 28 in poor condition
or pain were subsequently euthanized or perished on their own.
Researchers and volunteers are
still trying to nurse back to health 26 rough-toothed dolphins that survived
after being moved to several South Florida dolphin rehab centers.
Report: Sonar likely affected
Puget Sound orcas
Thursday, March 17, 2005 SEATTLE,
Washington (AP) -- Sonar pulsing from a Navy guided-missile destroyer during
training exercises near the San Juan Islands two years ago was likely loud
enough to send killer whales fleeing, according to a government agency report.
The National Marine Fisheries
Service (NMFS) report backed up local experts who said sonar from the USS Shoup
caused a group of orcas to behave abnormally, apparently trying to avoid the
SHOUP (DDG 86)
It contradicts the Navy's
previous findings that orcas in Puget Sound's J Pod seemed unaffected by the
sonar coming from the Shoup on May 5, 2003.
The 10-page report, dated January
21 but not released publicly until March 10, said the Shoup's sonar was not loud
enough to cause the whales any temporary or permanent hearing damage.
Credit:FAO Fisheries Global Information System
Cmdr. Karen Sellers, the Navy's
spokeswoman for the Northwest, acknowledged the Shoup's sonar signals were the
"dominant noise event" experienced by the orcas that day. She said the
Navy maintains the "biological significance" was minimal, The
(Bremerton) Sun newspaper reported Wednesday.
Ken Balcomb of the Center for
Whale Research in Friday Harbor said whether the whales suffered hearing loss is
beside the point.
"They are trying to get
away, and they are stranding and dying. It is irrelevant whether they had
hearing loss if they are dead," Balcomb said.
Marine mammal researchers have
also expressed concern about 15 harbor porpoises found dead in northern Puget
Sound in the spring of 2003. Sellers said the Navy stands by its conclusions
those deaths were not related to sonar.
The NMFS report said scientists
found no signs the porpoises' ears suffered any acoustical trauma, although
decomposition hindered researchers' analysis.
Puget Sound's orca population has
been proposed for listing under the federal Endangered Species Act.
The Canary Islands authorities
have asked Nato to halt a naval exercise in the area, fearing it may be
responsible for the death of 17 whales washed up on the coast of Fuerteventura
and Lanzarote this week.
The heads of six Cuvier's beaked
whales have been taken to the veterinary department of Las Palmas University for
examination, in particular to discover if their inner ears were damaged by
pressure from sonar devices.
Cuvier's beaked whale
Image credit: Garth
Mix, GMIX Designs
The exercise Neo Tapon 2002,
organised by the Spanish navy and involving about 30 Nato ships and submarines,
is being held in the Atlantic between the Canaries and Gibraltar.
They include the US frigate De
Wert, which specialises in anti-submarine warfare.
USS DE WERT (FFG
Two months ago a new
sonar system, Surtass LFA, was authorized for US naval use, despite fierce
lobbying by conservationists who claimed that sonar had been responsible for the
mass death of whales in the Mediterranean and off the Bahamas.
The US government gave the navy a
five-year exemption from the Marine Mammal Protection Act after tests led to the
conclusion that the system was unlikely to injure marine mammals.
One of the independent marine
biologists conducting the tests, Dr Kurt Fristrup, said: "If the stranding
is tightly correlated in time and space to the Nato exercise, this will be
another clear indication of an environmental issue that must be studied."
A Greenpeace spokesman in the
Canaries said the link was clear, but a Nato spokesman said that by the time the
whales were found dead the ships involved were 500 miles to the north-east.
The Surtass LFA system can
transmit signals as powerful as 215 decibels and the US navy says its use is
vital in helping to detect super-quiet submarines. Some scientists believe that
a whale's eardrums can explode at 180 decibels.
Beaked whales which were
studied after the Bahamas incident in March 2000, when eight died, were found to
be bleeding from the ears, and there was evidence of damage consistent with an
intense pressure injury.
Whales Die in
Beaching Incident in The Bahamas
22,2000-Fourteen whales beached and
eight of them died soon after the U.S. Navy conducted anti-submarine
exercises off the northern Bahamas.
trying to help a beached whale
Navy Cmdr. Greg Smith said
the tests took place from about 1 p.m. to 5 p.m. March 15 off Abaco Island
— part of a series of exercises testing ``sonar buoys'' that were to
continue through March 22.
P3 Orion Aircraft
Marine biologist Ken
Balcomb of the Earthwatch environmental group said beachings began that same
day, and within two days at least 14 whales had grounded themselves on Abaco,
Grand Bahama to the north, and Eleuthera to the south. Eight died, prompting
investigations by Bahamian and U.S. scientists and authorities.
``A whale beaching in the
Bahamas is a once-in-a-decade occurrence,'' said Balcomb, an American who
has been studying whales around Abaco island for nine years.
``We will be making
recommendations to the Bahamian government that these sort of exercises be
terminated,'' he said. ``The fact that it coincides with the military
exercises cannot be just coincidental.''
But the Navy spokesman
said there was no evidence linking the two events. ``My understanding of the
actual locations would put the island between the operations where the `sonobuoys'
were located and where the whales eventually beached themselves,'' said
Balcomb said the mammals
included several deep-water beaked whales, goose beaked whales measuring
16-19 feet, dense beaked whales measuring 10-13 feet, baleen whales
measuring up to 27 feet and some small minke whales.
Smith said the exercise
was testing for upgrades of what the Navy calls the Directional Command
Activated Sonobuoy System.
The exercise involved a
Navy P-3 aircraft dropping two buoys north of Abaco, one as close as 35
miles to the island, the other 70 to 75 miles from the island. One buoy
emitted a sonar signal which was received by the other, and a submarine was
moving between the two buoys.
Marine scientists have
been expressing growing concern in recent years about the possible effects
of man-made noises on marine mammals who rely on their hearing perhaps more
than their sight.
The mass stranding
occurred less than a week after two other whales washed ashore in a
different part of the Bahamas during a period of "live fire" naval
exercises in that region.
A Navy spokesman in
Virginia said yesterday that the Navy had followed all standard procedures
to protect wildlife in the area and had concluded there was no connection
between the exercises and the strandings.
Navy Tests On Whales
3/4/98 - The U.S. Navy
began aiming piercing blasts of underwater sound at humpback whales
Wednesday, testing a new sonar submarine detection system that
environmentalists say could harm the endangered marine mammals.
tests, designed to see how the whales react when bombarded by deafening
noise, were cleared to begin after a federal judge in Honolulu Tuesday
refused a request by environmental groups to stop them.
week from today we're going to go back to ask for an injunction,"
said Paul Achitoff, the Earthjustice Legal Defense Fund lawyer who filed
the failed request for a restraining order.
will go back to this same judge and try to persuade her that she
misunderstood the situation."
Low Frequency Active (LFA) sonar tests, being run for the Navy's Space and
Naval Warfare Systems Command, will use huge transmitters towed behind
ships to pump sound into waters just a few miles from the new Hawaiian
Islands Humpback Whale National Marine Sanctuary.
tests are part of a project to develop a new long-range sonar system to
detect "quiet" submarines by flooding the oceans with soundwaves.
groups, including Greenpeace and the Animal Welfare Institute, have
described the noise as "a thousand times louder than a 747 jet
engine" and say it could harm the whales in their favorite breeding
really have no idea how this is going to effect the whales, let alone
other marine life," Achitoff said. "It is really a question of
looking for a pain threshold."
scientists acknowledge that LFA will use sounds of up to 215 decibels to
see how loud a sound must be before it causes a "behavioral
change" in the whales.
they say the test will not harm the humpbacks, and will help the Navy
avoid disturbing marine life in future by obtaining data on what exactly
the whales can and cannot tolerate.
tests have already been conducted on whale populations off the California
coast without any noticeable adverse effect, navy scientists say.
March 4 1998 - NATO tests of
an underwater sonar system could have caused a mass stranding of whales off the
coast of Greece, scientists said today.
Twelve Cuvier beaked whales, a deep diving breed that is rarely stranded, washed
up on the west coast of Greece in May 1996 just days after the North Atlantic
Treaty Organisation tested a Low Frequency Active Sonar (LFAS) system used to
detect diesel and nuclear submarines.
Alexandros Frantzis, and colleagues at the University of Athens, think the two
events are more than just a coincidence.
"We know that LFAS was used in the Kyparissiakos Gulf. We also know that no
other LFAS or mass strandings have occurred in the Greek Ionian (Mediterranean)
Sea since 1981," he said in a letter to the scientific journal Nature.
"Taking the past 16.5 year period into account, the probability of a mass
stranding occurring for other reasons during the period of the LFAS tests is
less than 0.07 per cent."
The LFAS generates very loud, low-frequency sound which enables long detection
ranges. Although its effect on whales has not been studied thoroughly, many
specialists think that at high levels it could physically damage the whales and
affect their behavior.
Mass strandings of the creatures are extremely rare. Since 1963 there have been
only seven cases worldwide of four or more whales and three of them occurred
near the Canary Islands during similar military maneuvres.
The latest stranding was also odd because the animals were not stranded
together, but over a 40 kilometre area. Deep diving whales also seem especially
affected by low-frequency sounds, even at low levels.
Frantzis said that more information is needed to solve the mystery, but
unfortunately most of the data about the use of LFAS are a military secret.
The Director of NATO’s SACLANT Undersea
Research Centre (SACLANTCEN) announced the public release of the findings of two
panels, which convened in June 1998, relating to protection of the marine
environment. A Bioacoustic Panel was formed to make assessments and provide
advice and recommendations on an incident of whale strandings in Kyparissiakos
Gulf (Greece) in May 1996. A second panel met to evaluate SACLANTCEN
environmental policy and mitigation procedures and suggest improvements.
Information was received in the fall of
1997 that a stranding of Cuvier’s Beaked Whales occurred (in May 1996) in the
same general time and area in which NATO sonar research was being conducted.
Based on that awareness, NATO scientists began to reexamine the acoustic data
collected during that time. The issue received public attention in March 1998,
when correspondence on this matter was published in the journal Nature.
The NATO Supreme Allied Commander,
Atlantic established guidelines for two panels to investigate the stranding
incident and to review NATO procedures for protection of the marine environment.
It was requested that the NATO Nations nominate national experts in various
disciplines to sit on the two panels. The two panels were tasked to write
reports to be reviewed for public release.
The Bioacoustics panel met in mid-June
1998 to investigate circumstances surrounding the stranding of Cuvier's Beaked
whales (Ziphius cavirostris) on the Greek Coast in Kyparissiakos Gulf in
May of 1996. The NATO Research Vessel Alliance had been conducting sonar testing
in Kyparissiakos Gulf at the time of the strandings. The following summary of
findings regarding possible causes and panel recommendations are quoted from the
panel report. Bioacoustics Panel Summary of
Acoustic and behavioural
An acoustic link can neither be clearly established
nor eliminated as a direct or indirect cause for the May 1996 strandings.
Behavioural responses to acoustic transmission must
be taken into consideration as a possible cause for strandings: therefore,
acoustic characteristics that induce behavioural changes or physical damage to
marine animals should be determined.
The effects of sound on marine mammals vary according
to species; therefore, additional research is needed to determine hearing
characteristics and behaviour of the entire range of marine species.
Biological and Chemical Agents
Because of the lack of a comprehensive necropsy and
complete tissue analyses, the possibility of a pathological cause for the
strandings cannot be eliminated.
Based on reasonably comprehensive data, no physical
environmental factor was found to be a causative agent for the strandings.
Biacoustics Panel Recommendations
With regard to high intensity acoustic sources, there
was a strong recommendation from the panel that appropriate environmental
assessment procedures be implemented as soon as possible with a view to
recommending suitable mitigation and monitoring protocols.
The panel also noted the lack of adequate anatomical
data on the stranded animals, particularly auditory and other tissue analyses,
was a serious obstacle. It is acknowledged that an exceptional effort was made
by the Hellenic Cetacean Research and Conservation Society, considering the
resources available; however the panel recommended that proper specimen
collection be supported to ensure complete necropsy in the future.
The Environmental Policy and Mitigation Procedures
Panel met in June 1998 at the SACLANT Undersea Research Centre in La Spezia,
Italy, to review and provide expert opinion on a draft policy by the Centre for
protection of the marine environment. The panel reviewed procedures for the use
of active sonar and methods of monitoring and mitigating procedures used during
active sonar trials. The panel consisted of sonar, marine mammal and
environmental policy experts nominated by NATO nations. Based on available
knowledge and the results of the Bioacoustics panel, the Policy Panel gave
valuable guidance to SACLANTCEN on the further development of its policy to
conduct sonar research. The results of this review have resulted in the
production of SACLANTCEN Human Diver and Marine Mammal Environmental Policy and
SACLANTCEN Human Diver and Marine Mammal Risk
This policy and summary of the panel proceedings may be
found at the SACLANT Undersea Research Centre's web site on the World Wide Web,
at http://www.saclantc.nato.int/whales/, published in Adobe Acrobat
format. For further information on the SACLANT Undersea Research Centre, see .
For further information on the Supreme Allied Commander, Atlantic, see . Further
inquiries should be directed to the Public Information Office at the
Headquarters of the Supreme Allied Commander, Atlantic, in Norfolk, Virginia,
compiled from The British Antarctic Study, NASA, Environment Canada,
UNEP, EPA and other sources as stated and credited Researched by Charles
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