Dear MARMAM
A report on the common dolphin mass stranding event that
occurred in
An associated news piece may also be of interest:
NAVAL EXERCISES COULD HAVE STRANDED DOLPHINS, SAYS REPORT
Naval exercises could have contributed to the mass stranding
of 26 dolphins on the Cornish coast a year ago, a scientific report found today.
The pod of dolphins beached themselves at four separate
locations around the Percuil river near
At the time, rescuers said they believed the worst mass stranding
of the marine mammals in
According to the today's study led by Zoological Society of
London (ZSL) researchers, sonar used in the exercises was "highly
unlikely" to have directly caused the dolphins to beach themselves.
But the activities of the Navy could have been a
contributing factor in pushing the marine mammals close to shore and put them
at risk of beaching.
Dr Paul Jepson, of ZSL, said: "We don't have definitive
information but we've ruled out everything else, and it's possible that
something in the naval exercises caused the mass stranding."
The study said a definite cause for the stranding could not
be found, although the dolphins could have reacted to a "trigger"
event or suffered an "intrinsic error of navigation".
The research said the common dolphins were unusually close
to shore and at a greater risk of beaching themselves - possibly because they
were in unfamiliar waters.
Naval activities such as the use of sonar for anti-submarine
training could have been a factor in the dolphins, which are sensitive to underwater
sounds, coming closer to shore.
Natural behaviour such as foraging for food could also have
played a part.
The ZSL researchers said information supplied by the
Ministry of Defence (MoD) under the Freedom of Information Act showed several
days of "mid-frequency sonars for anti-submarine warfare training"
ended some 60 hours before the stranding.
A "short-range side-scan sonar" for sea-bed
mapping trials was used by the Navy the day before the dolphins beached
themselves, but the technology is common and has not been implicated in
strandings, the study said.
As a result the use of underwater sonar in the Navy
exercises was "highly unlikely to have directly triggered the mass
stranding event", but the researchers believe other parts of the exercises
could be to
blame.
The study also ruled out other potential causes including
disease, poisoning, attacks by killer whales or bottlenose dolphins and even earthquakes
as the reason for the mass stranding - only the fourth
recorded in
In the wake of the report, the Whale and Dolphin
Conservation Society said it believed that as all other potential causes had
been ruled out, the military was to blame of the strandings.
"Something frightened them ashore, way up inside the
river system, where this species in not generally known to go.
"The unusual behavioural response of all these groups
of otherwise healthy animals was triggered by something.
"An 'error of navigation' would not lead this many
dolphins to strand, and other groups to behave in such an unusual manner, on
the same morning - but over a distance of 20km."
She called on the Ministry of Defence to conduct transparent
environmental assessments of its exercises to see what effect they were having
on marine life, and to suspend use of sonar once a stranding
occurs until rescued animals are out of danger.
The mass beaching in
No cause could be found for the other event, in which a
number of long-finned pilot whales and various species of beaked whale were
found stranded in Scotland, Wales and Ireland over a three-month period at the
beginning of 2008.
The annual report for 2008 from the UK Cetacean Stranding
Investigation Programme, also published today, revealed the number of dead and stranded
whales, dolphins and porpoises increased by 6.2% on the previous year.
Some 583 cetaceans were reported to the programme, of which
485 were found stranded and dead, 81 were live strandings and 17 were found
dead at sea.
The most common species reported were harbour porpoises
which were mainly found to have died of starvation, disease, attacks by
bottlenose dolphins or as a result of being accidentally caught by fishermen,
and short-beaked common dolphins, which mostly died as a result of stranding themselves
live, the report revealed.
WDCS Noise Pollution Campaign Manager
Sarah.dolman@wdcs.org