Friday, August 24, 2012

Day 15: Calm Waters, Calm Dolphins

Three rough-toothed dolphins. (Photo: A.J. Milette-Winfree
permit # 15530 to CRC)

We had glassy Beaufort 0 – 1 waters for a good part of our day today. This type of water is ideal for finding difficult to see, far off marine mammals. Our two research vessels searched these waters for a combined 263 km. While we did not find melon headed whales or our ever elusive false killer whales, we did have a unique encounter with a group of rough-toothed dolphins (Steno bredanensis). When sighted off of the Big Island, these dolphins are often evasive, making photo-id and tagging a very difficult endeavor. Today however, this pelagic and poorly known species gave us a great opportunity to collect a wide range of data. We were able to photograph each individual in the group, record their acoustic signals using the towfish, and collect 2 biopsy samples for genetic analysis. This was our best towfish recording yet, giving us a wealth of echolocation clicks which will add to our growing catalog of rough-toothed dolphin signals. Renee Albertson of Oregon State University, who is part of our research team, was particularly thrilled with our data collection today. The biopsies and associated data we collected will provide her with valuable data for her PhD research on rough-toothed dolphin population structure.

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