Earthwatch team members and scientists observe and record dolphin movements from two different locations. One crew works with binoculars and a surveying tool from the top of a high cliff overlooking Kaikoura Bay. When dolphins are sighted, team members note the group size and behaviors — resting, traveling, socializing, feeding. The surveying tool is able to record the location of the dolphins, the direction, and the speed of travel.

At the same time, volunteers track and record the numbers and movements of tourist boats, swimmers getting in and out of the water, and helicopters or planes passing over the dolphins. One great advantage of the shore observations is that the observers do not affect the animals being watched.

While the first crew is on the cliff, a second crew, in radio communication with the "cliff" crew, is on the water in a small boat near the dolphins. The team on the boat records dolphin locations and behaviors, and photographs the dorsal fins of individual dolphins with a digital camera. About one in three dolphins has identifiable markings, mostly in the form of nicks and notches on the dorsal fin. Dolphin sounds are taped with an underwater recorder.

At night back in the lab, Earthwatch team members download onto a computer the images of dorsal fins captured each day. They try to match the images with photographs of fins of individual dolphins that have already been catalogued, The catalogue contains over 1,000 individuals. There are repeated sightings for about 200 dolphins.

From the photographs Würsig has been able to determine that Kaikoura's dusky dolphins are part of a larger, revolving population. The dolphins appear to leave the area, and then return again on a fairly regular seasonal basis. Some of the dolphins appear to have preferred traveling companions. They can be found repeatedly together in small groups even after months have passed.

While the social organization of the dolphins may appear to be without structure, the scientists are finding that it is very orderly. Much more remains to be discovered about the fascinating social world of dusky dolphins and their adaptability to different ocean environments.

Photo courtesy of Tim Markowitz/Earthwatch Institute