Sperm Whale Seismic Study (SWSS)

Summer Breeze Daily Reports - June 17, 2005

Supplemental Report

Position at 29.07  87 49

Our day started with an encounter with a pod of approximately 200 melon-headed whales. Some of them came to bow-ride, but most of the group seemed to be resting and were happy for us to drift amongst them. Smaller groups were engaged in a variety of behaviors, many of which involved activities which were clearly visible at the surface, such as spy-hops and flipper slaps. They were as well very active acoustically, mainly producing whistles. We made some excellent recordings and the group was audible for many miles during our regular monitorings after we left the pod.

Group of Melon Headed whales bowriding.

White lips and a triangular shaped head are characteristic features of melon headed whales.

By mid morning we could see the first of the big offshore rigs on the horizon and in a strange way it felt like being home.  At around 10:30, we detected sperm whale clicks and by 11:00 we had visual contact.

This turned out to be a dispersed group of around five animals that we judged to be maturing males.  We obtained some fluke photographs over a couple of dive cycles but the whales then went into a resting mode, eventually rafting up in a tight group of five, logging and traveling slowly northeast at the surface. For the next three hours, we slowly followed behind the four whales, waiting for them to fluke. But fluking seemed furthest from minds. Occasionally, one individual would become more active and we witnessed some spectacular breaches and lobtails. Finally, as the light was fading, at 20:00, the whales decided to start diving again. Our patience, following the whales through the long hot afternoon was rewarded and we got good fluke shoots from most of the group. After following them for almost 10 hours, we called it a day--just in time for a swim, CTD cast before hunkering down in a lightning storm, during  dinner. We rode out the storm for a while, choosing the most comfortable and dry heading.

Our group of sperm whales were encountered quite close to rig PETRONIUS

Now we are making the most of the wind heading northwest, we’ve just passed another sperm whale group but will hope to find and track one later in the night before morning.

This was the first time our new team members worked with several whales at the same time, and things went well. We will improve some of our Logger forms to allow for a better flow of entering data during multiple encounters, and figure out the best way to communicate between the people at both ends of our boat (the hands-free walkie-talkie sets have the disadvantage of being triggered by the constant wind).