Thursday, August 20, 2009

Many Beaked Whales (most with calves)

We had another very good day today in terms of wind and sea conditions. We consequently found many cetaceans, including our primary species of interest. We worked mostly in the deep axis of the same canyon area and detected many groups of Cuvier's beaked whales throughout a very long and full day of activity. Acoustic surveys begin at 0500, visuals come on at dawn, and both teams operated continuously throughout the day with these many animals. As you can see from the picture here, it was another pleasant sunset but we just missed getting a tag on at the very end of the day.

Around 20 different groups of beaked whales were sighted, in addition to a large number of the four other species we've been seeing regularly out here (pilot whales, and common, striped, and Risso's dolphins). While it is likely some of these were the same groups at different points in the day, or different combinations of groups (they do come together and break off from one another), with the distance we traveled it is likely we detected a dozen or so distinct individuals or groups. This confirms earlier evidence that this is an excellent place to find these elusive animals when the conditions are right and we have the capabilities that exist on this ship. However, despite the large number of sightings, it took many hours to find a good candidate group, as almost all those we found today (as yesterday) had one or more calves or were single individuals. In the late afternoon we found a good group of adult and sub-adult animals that we tracked for about four hours, both visually and acoustically through relatively shallow surface intervals and one deep foraging dive (after which we found them at the surface again). We vectored the tag boat during the subsequent surface intervals and we again came tantalizingly close (within a few feet) of tagging the animals before they slipped into the depths again.

We expect good conditions again tomorrow and will give it our all again. We will be trying some similar areas where we hope to be less likely to find so many groups with calves that we cannot work around. Despite it impacting our ability to work many of the groups here, the large number of calves is encouraging and we are learning some interesting things about the ecology and behavior of these poorly known animals in when and where we find groups with different social structure. It is remarkable how challenging these animals are to work with, even with the amazing amount of expertise and technology available to us, but we know this can be done and we should have another good chance tomorrow if the forecast holds true.