Additional information on the Bahamas beaked whale survey project
Opportunistic and Systematic Surveys for beaked whales and other marine mammals off the east coast of Central Abaco.
One quarter of the world’s 80 whales and dolphin species belong to the family Ziphiidae, the beaked whales. However, little is known about most beaked whale species because they favour deep-water habitats and study and knowledge of these cetaceans is in its infancy. Sightings of beaked whales at sea are rare due to their unobtrusive surfacing behaviours and their long dive times. Based on strandings data and limited observations at sea, beaked whales are thought to be some of the longest and deepest diving of all marine mammals. Beaked whales appear to be particularly sensitive to some man-made sounds, such as certain sonars as evidenced by several recent strandings events in the Mediterranean, the eastern Atlantic and The Bahamas. The conservation status of these species is unknown.
1. Document population of beaked whales and other cetaceans off the east coast of central Abaco.
2. Photo-identification of individual animals using 35mm film and digital video.
3. Document distribution of cetaceans within the area and compare this to the distribution of other species of marine life and oceanographic variables.
4. Opportunistically collect sloughed skin and faecal samples for genetic analysis.
5. Carry out surface and underwater behavioural observations of dolphins & whales.
6. To record and assess diving behaviour of beaked whales and sperm whales in the area.
7. To attach a suction cup acoustic tag and/or a “CritterCam” video tag to the back of a beaked whale or other cetacean species opportunistically.
8. Involve and engage Abaconians in research process to further their
understanding of and commitment to marine conservation through public
outreach sessions offered to schools and community groups.
Identification photographs (photo-I.D.) will be taken of the unique markings of each whale encountered. Photo-I.D.s will be acquired using 35 mm still cameras equipped with telephoto lenses and using digital video cameras. Field data, including behavioural mode, individuals present, geographic position, date, time etc. will be collected using voice recorders. All images will be digitized and data transcribed and subsequently integrated into databases. Photo I.D.s will be entered into a beaked whale catalogue to monitor individual whales residence and patterns of association.
Genetic material (DNA) coded with individual whale’s attributes can be gleaned from samples of their skin. Skin sloughed off as whales dive or exhibit high-energy behaviours will be collected as whenever possible. Samples will be logged with a unique access number, allowing cross reference of photo-I.D. and field data with genetic material. Samples will be preserved and stored according to established protocols for later analysis. DNA will be analyzed to confirm species, and determine sex and relatedness of individuals. On a larger scale, samples will be compared with those in existing databases to assess population identity and genetic diversity in beaked whales world-wide.
Acoustic Tagging and Monitoring
With a time expansion system, we record two seconds of data then listen to it played back at 20 seconds duration. There may be a 30 kHz peak energy pulse from Ziphius, which would be unique to the species. If such an acoustic clue could be found for densirostris, we could perhaps track the animals underwater in real time. We plan to apply suction cup tags with a pole to species of Mesoplodon, Ziphius, Kogia or opportunistically to other species. These tags record acoustics, roll, pitch, and depth continuously on a common time scale and are recovered to access the recorded data. A small VHF radio transmitter is attached to help locate the tag after it detaches from the whale. This typically occurs in several hours.
We will make passive acoustic recordings using hydrophones and high speed ultrasonic recorders to learn what sounds are being produced by whales within the study area.
Crittercam is a microprocessor-controlled imaging and data collection device. Its purpose is to provide scientists with an unprecedented viewpoint onwild animals' behavior and biology. The larger of the basic Crittercam
systems is 4" in diameter and 12" long,including the buoyant foam tail section. This system is capable of up to
6 hours of video recording. The smaller system is only 3" in diameter and 11" long, including the foam tail. It can record up to 2 hours of video. The functioning of both systems is controlled by a program loaded into its microprocessor. Both systems have the option of headlights, whichprovide illumination for night-time or deep-diving behaviors. In some cases, an image intensifier option ('night-vision) can be used.
The system is typically deployed from a boat, using a long pole to place the tag on the animal. An active suction is used so that the placement can be done quickly and firmly. We have seen no evidence that the cup has any lasting effects on the skin. We have even stuck the cups on our team members finding that they were not painful nor left any lasting marks.
The cups are designed with redundant release mechanisms: one that is triggered by the program in the Crittercam, and a second, independent one that will release the system a short while later if the programmed trigger fails for any reason. The systems are buoyant and equipped with a VHF transmitter, so that when they release from the animal they float to the surface for recovery. (K. Abernathy)
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