Blainville’s Beaked Whale, Abaco, Bahamas
SIGHTINGS REPORT OCT – DEC 2012
The last quarter of 2012 produced relatively few open-ocean CETACEAN sightings, not least because of a reduction in spotting trips during the period, with some members of the team elsewhere in the world completing their research. SIRENIAN activity is thankfully on the increase, with reporting opportunities increased by the manatees’ preference for sticking close inshore, usually in harbour areas. Georgie has gained her first yellow spot as Abaco’s only resident manatee following her long trip over from the Berry Is. (and away from mother Rita) last summer. She has taken up residence in Cherokee. She performed a worrying vanishing trick during Hurricane Sandy, holing up (presumably) in seagrass off-shore, and (definitely) in an inshore channel for some of the time. She went AWOL again before Christmas, but has returned to Cherokee in good condition after a short vacation. Having shed her tag (several times) it was not possible to track her. The big plus is that she has proved capable of independent living, and has not become reliant on proximity to humans and their offerings of cabbage leaves etc… This photo was taken at Cherokee a few days ago.
The other notable new entry is a manatee sighting in the Freeport area of Grand Bahama. A single photo exists – a head shot – but it hasn’t been possible to identify the creature as a known one. (S)he may be a new visitor to the Bahamas. People in the area are asked to report any further sightings in the area to the BMMRO – and if possible to get a picture!
RANGE MAP IUCN RATING “DATA DEFICIENT”
Mid-frequency broadband sounds of Blainville’s beaked whales
Recent research has been carried out on the sound variations of this relatively little-understood species of whale. “Recordings from acoustic tags show that five Blainville’s beaked whales produced mid-frequency broadband sounds on all of their deep dives, with each sex producing two different sound types. These broadband sounds are atypical of the regular echolocation sounds previously described for this species. One male produced a total of 75 sounds over four dives, between the depths of 109 and 524 meters, and four females produced a total of 71 sounds over 18 dives, between the depths of 305 and 1289 meters. Ninety-six percent of the male sounds and 42 percent of the female sounds were produced before the onset of foraging echolocation sounds, and all were produced before the deepest point of the dives. These sounds may be candidate communication signals, with their production timed to mitigate the risk of both predation and hypoxia (oxygen deprivation).”
The report includes sample sounds from the 3 BBWs shown below, and the one heading the page. I haven’t found a way to embed the sounds, but I am working on it (there’s a time -consuming method involving conversion to MP3, but maybe another day…)
Thanks to the prolific DEAR KITTY for a cross-reference to this topic on her website, featuring a fine video of BBW in French Polynesia
Finally, the action-packed, information-filled, image-laden 4 page winter newsletter. Click below to open.