Sperm Whale Seismic Study (SWSS)

Summer Breeze Daily Reports - July 27, 2005

Position on July 27, 2005 09:18 UTC 27 15.8N 091 28.7W

Our whales seemed to go into a socializing mode in the very early morning, around 05.30. This makes tracking much more difficult as one only has sporadic codas to localize on, and the acoustic range of these is limited. It was a relief therefore at first light to see a group of seven whales gently blowing some 400m away. After an hour or so this sub-group, and the rest of the larger group were back in “feeding mode” so the rest of the day was fairly straightforward – but productive. With a large group and excellent weather we managed to collect 46 good photo-id sequences, for most of these we should get a length measurement from the fluke span too.

We are often struck by how animals that are almost the same size as adults behave as though they are suckling (repeatedly diving below the adults’s tail stock.) One of the “calves” today was not only nearly as large as the adult it seemed to be suckling from but had a well formed dorsal fin callus. (Dorsal fin calluses are a reasonably good indication that an animal is a mature female.) One has to have some sympathy for these adults apparently continuing to “support” nearly fully grown animals. It’s a situation with which many parents of teenage children might empathize.

We’ve decided to leave this group and return to survey mode as we make out way back to our main survey area and the Mississippi Canyon area.