Wednesday, February 17, 2010

A Conversation with Mr. Oarfish

As a kid, I had a collection of flashcards with pics of fish on one side, and their specs on the other. The oarfish stood out as the weirdest and most captivating of the lot.

One of the folks I bump into fairly regularly at the Institute is an ichthyologist...a fish expert. Over lunch, I asked him if he had seen the recent video of an oarfish in deep waters:

I expected my acquaintance to express surprise that such a video existed. Instead, I got a 30 minute lecture on the subject of oarfish. It turns out he might be the single most oarfish-knowledgeable individual on the planet. He didn't seem thrilled about the possibility that I'd blog on his knowledge, possibly because some of his opinions haven't been thoroughly vetted by the science community, so I won't offer his name. But here's what I recall:

The video shows the oarfish in a vertical position. Mr. Oarfish expressed skepticism that the fish, Regalecus, actually spends sizeable amounts of time in that position; it might be reacting to the unmanned submersible taking the video or to its environs (which include the massive vertical risers of an oil rig). At the same time, he theorizes that the oarfish may drift vertically in a catatonic state for thousands of kilometers.

I had read that the video was special because previous footage of Regalecus had been taken near the ocean surface; in such a state, the creature would tend to be near death. Mr. Oarfish replied that there's no reason to believe that healthy oarfish don't spend sizeable periods of time near the surface.

Perhaps the single most famous oarfish shot is the following:

The pic is well-known in Thailand. The Thais seem to think we're looking at Vietnam vets somewhere along the Mekong. This notion ties in nicely with the belief that dragons, the Phaya Nak, abide in the Mekong. Mr. Oarfish points out that the uniforms aren't from the Vietnam era. The pic was taken in 1996 near San Diego.

What's more, I had heard the soldiers dined on the serpent following the photo shoot. No, says Mr. Oarfish, the fish was far too decomposed. In fact, he only knows one person who has tasted Regalecus, and that individual was none too impressed with the result. A lousy cook, perhaps.

Some of the maximal lengths are exaggerated. Anything over 8 meters is suspect. An oarfish can actually lose or shed large chunks of its distal region, gecko-like. The resulting sawed-off appearance might lead one to extrapolate wrongly.

Strictly speaking, the species we're talking about here is Regalecus Glesne (Glesne being a town in Sweden). But Mr. Oarfish says there is certainly more than one species that is commonly labeled R. Glesne; there were some fairly large differences in mitochondrial DNA sequences (around 12%) taken from oarfish in Japan and in the Atlantic. What's more, there are significant morphological differences (e.g. in the number of vertebrae).

The evolutionary history of the creature is somewhat murky. One partial fossil from Italy exists, dating back about 1.5 million years...not long enough to display clearcut trends in evolution.

A couple final tidbits...dogs seen oddly attracted to the scent of the fish. And...there's very little evidence of the sorts of predators the oarfish may have to deal with. Sharkbites are rarely, if ever, seen on the creature.

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