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Wednesday, September 17, 2008

Brad Hanson Lecture

Brad Hanson's lecture tonight at The Whale Museum was full of all kinds of thought-provoking information about killer whales. He's another one of those scientists that inspired me, in part because while his work is biologically interesting in terms of animal behavior and evolutionary biology it is equally important in terms of conservation. Some of his many projects include collecting fecal samples, prey samples, and tissue biopsies of the Southern Residents.

One brand new project involves putting state-of-the-art tags on transients. As you may or may not know, there haven't been many successful attempts at putting a long-term tag onto a relatively small cetacean (into which killer whales fall - large cetaceans are like blue and humpback whales) because there hasn't been any technology that's small enough to involve a non-invasive attachment mechanism. For instance, when two transients were tagged in the 1970s, it involved attaching a tag via surgically bolting through the dorsal fin - the whale that still survives today still shows distinctive scars from the incident, which occurred while he was in a net pen. However, a new miniature dart tag has been developed that can stay on for more than two months and causes only minimal tissue damage, and over the last couple of days three transients have been tagged locally.

The best part is, we can follow the progress of these whales as they post updates on their research website. The above map is taken from the Cascadia Research site, showing the progress of T30A during the first day and a half after being tagged. Amazingly, these tags don't use GPS technology, but rather Doppler shift, so as it sends a signal to a NOAA weather satellite, the satellite can estimate the position of the signal.

And for you biologists out there, here's another interesting tidbit I learned at the lecture: worldwide, killer whales are very similar genetically. Since you find unique populations of killer whales everywhere in the world in terms of foraging and social structure, you'd expect genetically distinct populations. However, that's not the case....for instance, the Northern Residents and Southern Residents only have a 1 base pair difference! This suggests that one of two things are the case. Either 1) There was a recent global genetic bottleneck for killer whales, and all the "speciation" we've seen between the different ecotypes is a relatively recent and relatively quick occurrence, or 2) these populations actually interbreed. Either one would be a huge change in the current belief about killer whale life history and evolution!!

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