Yesterday we managed another successful day off Cape Hatteras, despite marginal working conditions (Beaufort Sea State 4 for much of the day). We had four sightings – each of a different species – and managed to deploy two satellite-linked tags and obtain two biopsy samples.
Our first encounter was with approximately 30 offshore bottlenose dolphins (Tursiops truncatus) near the shelf break, approximately 35 miles from shore. The animals were playing with Sargassum – tossing pieces of it in the air and draping it over their dorsal fins. We deployed a single location-only satellite tag on an animal in this group and obtained two biopsy samples from well-marked animals to confirm the ecotype of this group.
We then ran into about 160 short-beaked common dolphins (Delphinus delphis). These are winter visitors to our area, soon to depart for New England and waters further north. They love to bow ride and were playing with Sargassum. We contemplated deploying one of the small location-only tags, but it was rough and the group was a little chaotic, so we decided to just enjoy the show instead.
The common dolphins led us to pilot whales and, after some effort, we were able to deploy a location-only tag on an animal in this group of about 32 individuals. The pilot whales were also playing with Sargassum (it was that kind of a day).
We were still working with the pilot whales when we spotted a group of five Cuvier’s beaked whales surfacing nearby. Remarkably, the group contained the animal that we had tagged earlier this week, although the composition of the group seemed to have changed as it contained two heavily scarred animals, presumably adult males.
We approached for photos and were that close from deploying a second satellite-linked dive recorder on one of the adult males. We are getting great data from the first tagged beaked whale – with some dives to more than 2,000 m. Very cool. And nice that we have seen Ziphius on all four field days so far, confirming what Joy Stanistreet is hearing on her bottom-mounted High Frequency Acoustic Recording Package off Cape Hatteras.
We have a few weather days ahead of us this week but hope to be back on the water on Memorial Day weekend (always a crazy time to be offshore), so stay tuned for more updates.
