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.
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 "Sounding the Depths"
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. 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
More in www.whaleresearch.org
Bahamas Beaked Whale Survey