During August of 2006 our international team (Iceland, Japan, USA and Denmark) succeeded in capturing two white-beaked dolphins (Lagenorhynchus albirostris ) in Faxaflói Bay, Iceland. The animals were caught using the hoop net technique, where the dolphin is caught during bow riding by a catcher standing on a pulpit with a big net.

Video showing how the dolphin was caught (in Quicktime format).

The project had three objectives: Investigating the hearing, biosonar and movements.

First the animals were placed in a tank with water. In the tank we recorded the hearing curve by using electroencephalogram (EEG) methods where the brain response was measured with external suction cup electrodes when different sounds were played back to the animals. The audiogram indicates that this animal is more sensitive to very high frequencies compared to other dolphins and porpoises.

The white-beaked dolphis were caught using the hoop net technique, where the dolphin is caught during bow riding by a catcher standing on a pulpit with a big net. Photos: Jakob Højer Kristensen.

After the hearing measurements an acoustic tag was attached to the animals with a suction cup. The acoustic tag was recovered after almost 14 hours of continuous acoustic recordings and dive profiles. The animal used its biosonar mostly at the surface and at the bottom of the dives and very few clicks on the way down or up. During these hours the dolphin regularly dove to the bottom of the 50 meter deep bay.

A satellite tag was attached by two pins through the dorsal fin to one of the dolphins. The track from the animal can be followed by clicking on the map below.

Click on map to follow the dolphin.

For the first time this project showed that it is possible to get an audiogram from a wild dolphin and it is also the first time a white-beaked dolphin has been caught and tagged.

The project was supported by the Research Councils in Denmark and Iceland with partners from University of Southern Denmark, Marine Research Institute in Iceland, University of Hawaii, National Research Institute of Fisheries Engineering in Japan and National Environmental Research Institute in Denmark.