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Beaked
Whales?
One quarter of the world's 80 whale and
dolphin species belong to the family of beaked whales
(Ziphiidae), but because they favor deepwater habitat,
study and knowledge of these cetaceans is in its infancy.
Their conservation status, for instance, is completely
unknown. From the types of fish and squid recovered
from beaked whale stomachs, it is speculated that
beaked whales may be the deepest and longest diving
of all cetaceans. What little we know of beaked whales
has largely come from stranded animals. Sightings
of these elusive creatures at sea are extremely rare
due to their long dive times and unobtrusive surfacing
behavior.
That
is, until the past few years, during which researchers
in several parts of the world have finally been able
to study these elusive animals at sea. A long-term survey
effort by research organisations since 1991 has revealed
resident populations of two species of beaked whales,
Mesoplodon densirostris and Ziphius cavirostris,
in the northern Bahamas.
Beaked
whale breakthrough
Sightings are rare but always fruitful. Many long hours
at sea were rewarded when CCRC's
Nan Hauser and Hoyt Peckham recorded 28 captivating
minutes of these enigmatic whales underwater - in crystal
clear blue water on a glassy calm day. Each second of
digital video footage is invaluable for research purposes,
because until now we could only speculate on these whales'
biology from rare stranded specimens, skeletons, and
fleeting surface encounters. Check out the video!
Are
beaked whales the deepest and longest divers?
Acoustic recording tags developed
by a team of engineers and modified to withstand
the pressures associated with extreme depths will be
attached to beaked whales with suction cups. These tags
will record everything from dive profiles to ambient
sounds, offering an unprecedented window into beaked
whale diving behavior. We will find out more when we attempt to attach acoustic and Time Depth Recorder tags to the backs of these rare whales. Keep you posted!
Beaked
whale conservation - critical habitats
In
order to protect beaked whales, we must determine their
status. Elucidating their diving behavior will yield
much insight into their habitat requirements and possibly
their food preferences. Dive data will enable us to fine tune the pioneering
assessment of habitat requirements of beaked whales
in the northern Bahamas and the Cook Islands.
Colin Macleod's
research on Densebeaked whales and Cuvier's beaked whales,
along with the pioneering work of others such as Hal
Whitehead and his students on Northern
Bottlenose Whales (the largest members of the beaked
whale family), indicate that beaked whales have very
specific habitat requirements. Rather than being widespread
across deep ocean basins, beaked whales are most frequently
sighted around deep canyons, gullies, and walls, probably
because their prey are associated with these features.
As we learn more about beaked whale distribution, it
appears that beaked whales rely on isolated critical
habitats. To ensure the welfare of beaked whale populations
around the world, these critical habitats must be identified
and protected.
In
the first long-term study of beaked whales (launched
in 1998), Hal
Whitehead, Sascha Hooker and their students at Dalhousie University
have found that a population of northern bottlenose
whales relies on an underwater canyon off Nova Scotia
called the Gully. In the mid 90s areas of the Scotian
Shelf adjacent to the Gully known to be rich in oil
and gas resources were slated development, and it became
clear that proposed prospecting and extraction could
threaten the survival of the Gully's bottlenose whales.
Whitehead and colleagues vigorously sought protection
for the Gully and its diverse ecosystem, and in December
1998 it was designated Canada's first east coast Marine
Protected Area by the Department of Fisheries and Oceans.
A cooperative survey to identify beaked whale populations and their critical habitats around the world is in the making.
Beaked
whales and acoustic pollution
Cetaceans, because they communicate and navigate almost
entirely using sound, are sensitive to acoustic pollution.
Beaked
whales, because of their peculiar physiology
and deep diving, are especially susceptible to damage
resulting from acoustic pollution. Threatening sources
of acoustic pollution in marine environments include
widespread oil prospecting, ice-breaking, shipping noise,
and military sonar.
To
learn more see Natural
Resources Defense Council "Proliferation of Undersea
Noise"
On
four of the few occasions when more than five beaked
whales have stranded in a limited area over a short
period of time, naval sonar tests were being conducted.
The most dramatic of these events occurred on 18-19
March, 2000, when 17 cetaceans, 13 of which were beaked
whales, stranded in the northern Bahamas. CCRC researchers
assisted in collecting, documenting, and necropsying
these whales. Several of the beaked whales' heads were
flown to Mass Eye and Ear in Boston, USA, where Darlene
Ketten ran them through CAT scanning machines. Ketten's examination
revealed unmistakable evidence of acoustic trauma.
The
pattern of the strandings (small area, short time) and
Ketten's results indicated an unusual sound source.
Further investigation revealed that an international
naval battle group had been operating experimental sonars
while transiting the area. After pressure from the National
Marine Fisheries Service, NGOs including IFAW and NRDC,
and much public outcry, the US Navy has launched an
unprecedented review of its transit of the area.
Rather
than blaming the US Navy for killing these whales, CCRC
encourages the Navy to think more broadly about the
impacts of their sonar development projects. After all,
Navy engineers are striving to protect US interests
(warships, strategic waters, and Americans) from enemy
forces by developing the best possible sonar systems.
That said, we at CCRC firmly believe that adequate defense
systems can be developed which do not threaten cetaceans
and the marine ecosystems they inhabit. The US Navy
is required to factor the welfare of sound-sensitive marine
life into their sonar development.
Nan
Hauser strongly believes that the whale researchers,
the acousticians and the navy can work together, sharing
their knowledge and expertise, to find solutions.
Read
the interim National
Marine Fisheries Services / NOAA report.
Beaked
Whales in the South Pacific
Hauser launched an opportunistic survey of beaked whales
in the Cook Islands, South Pacific, in 1998 which coincided
with the instigation of the Cook
Islands Humpback Whale Survey. See Cook
Islands Beaked Whale Sightings in Whale
Adventures for firsthand accounts of recent sightings
of beaked whales in the Cook Islands, South Pacific.
Over the years Hauser has teamed up with Merel
Dalebout, PhD, Gerald McCormack of the Cook Islands
Natural Heritage Trust, and Cook Islands fishermen to
identify and document the beaked whales of the Cook
Islands.
Densebeaked whale off Rarotonga, Cook Islands
Additional
Resources
more in www.whaleresearch.org
Cook
Islands Beaked Whale Survey
Bahamas Beaked Whale
Survey
articles
Unidentified Beaked Whale Stranding in Japan
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