Beaked whales of Samoa

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This video says about itself:

Underwater footage of a unique encounter with a Blainville’s beaked whale in French Polynesia. Marine Mammal Study Group (www.gemmpacific.org)

From the New York Times in the USA:

Where the Beaked Whales Are

By SCOTT BAKER

Scott Baker, associate director of the Marine Mammal Institute at Oregon State University, writes from Samoa, where he studies the formation of local communities among dolphins and their genetic isolation from one another.

Wednesday, Aug. 15

I often think that finding a needle in a haystack would be relatively comfortable work compared with finding dolphins in offshore waters. If the dolphins do not approach the boat to ride the bow, the only sighting cue is the dorsal fin or the occasional leap. Add wind, waves and sun glare to create discomfort as well as tedium. Even when you find the dolphins, it is easy to lose them in the waves and whitecaps. It can be frustrating work, but interrupted with moments of excitement and the occasional discovery.

Today, we surveyed the offshore waters along the northwestern tip of Savai’i hoping to find rough-toothed dolphins. Previous studies in Hawaii and the Society Islands (French Polynesia) have found that this species prefers waters of 3,000 to 6,000 feet in depth. To improve our chances, we planned a series of surveys crossing this depth a few miles offshore of Asau, where we had anchored for the night. Although the morning began with calm seas, the wind and swell increased by late morning and the conditions for sighting the dolphins deteriorated. By early afternoon we had abandoned our survey track and were headed back to shore, feeling a little discouraged.

Then our luck changed. Just as I started down the ladder from the flying bridge to the deck, I thought I saw a blow.

As I called out to the others, the animal surfaced again and I could see it was too large for a dolphin. Before we had time to grab our cameras, the whale leapt fully into the air and dived. It was a beaked whale, one of the most elusive and poorly understood mammal groups. More than 20 species are currently described in the Ziphiidae family, some of which have never been seen alive. Beaked whales are primarily deep-diving species, spending much of their lives at great depths in pursuit of squid, their main prey. I have worked for many years on the molecular identification of beaked whales using DNA extracted from bones in museums, but this was my first encounter with a living beaked whale. It was over in an instant.

I knew that it was unlikely we would see the whale again, given the nearly hourlong dives that are common with these species. I quickly sketched what I saw on the back of our sighting form and showed it to Renee, Nevé and Titi. We all agreed that whale was about 20 feet long and robust in girth. The back of the whale was dark, and appeared brown in color. As it leapt, I thought I saw the characteristic “tusks” of a mature male – actually two teeth that erupt from the lower jaw. Beaked whale species are difficult to identify at sea, but it is likely that this was a Cuvier’s beaked whale, one of the most widely distributed members of this family. A biopsy sample would have allowed us to confirm the species identification, but collecting a sample was not possible in these conditions.

Encouraged by this sighting, we continued our offshore track despite the conditions. Remarkably, over the next hour we found a small but uncooperative pod of rough-toothed dolphins and sighted another beaked whale. This time, we had our cameras ready but got only a glimpse of the whale’s back before it dived. Based on the location and time, we think it unlikely that this was the same individual that we had seen an hour earlier.

Back at anchor in Asau, the winds abated and we enjoyed a few of the pleasures of work in Samoa. First, a swim in the warm lagoon with the glow of sunset for a backdrop. Then the melodies of the local musicians playing in the small resort where we anchored. Finally, the intense black night and bright starlight of the South Pacific.

See also here.

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