Friday, August 7, 2009

Tagging Pilot Whales

Today was predicted to have moderate winds. At first light, it was clear that it would be too windy to try to find and tag beaked whales, so we decided to work with pilot whales. As luck would have it, we heard distinctive sounds of pilot whales by 0700 and sighted them by 0800. One of the unusual things about pilot whales in this part of the Mediterranean is that they seem fascinated by ships. These whales came right over to the Alliance and inspected it, then swam along surfing in the wind-driven waves, following the ship for some time. We deployed the tag boat, which took photographs to identify individual animals, and attached tags to two adult female pilot whales. Unlike beaked whales, which are extremely difficult to find and approach for tagging, pilot whales are quite easy to follow and approach. In fact these whales approached the tag boat and the first whale was tagged within five minutes of the tag being readied for attachment. The tags attach to the smooth skin of the whales with four suction cups, and are attached using a long carbon fiber pole that you can see lashed to the port side of the orange tag boat. The whales showed little reaction, continuing to swim near the ship. The pilot whales form sub-groups that are usually well defined, although the subgroups will merge and separate at times. Adult males can be distinguished from adult females, and many females in these groups had calves, including neonates so young that fetal creases were visible. Under the conditions of our research permit, we did not conduct a sound playback with these groups, but we collected fascinating baseline data with bouts of complex vocalizations alternating with periods of silence. We tracked the tagged whale for more than six hours. After the tag released from the whale, it floated to the surface and broadcast a radio signal that we can use to recover the tag. Once the tag is recovered, we connect it to a computer and download the data before we can explore it.