Right Whale Skeleton
INTRO: Northern right whales are among the most endangered species in the world. Just a handful of them—perhaps less than a dozen—live in the frigid waters off Alaska. So rare are right whales that scientists haven't seen a right whale calf in the North Pacific Ocean in nearly 150 years. So it came as a surprise when scientists exploring the ocean floor in 1999 encountered the skeleton of a right whale. Doug Schneider has more in this week's Arctic Science Journeys Radio.
STORY: The discovery was made by scientists aboard the Alvin submersible during an exploratory cruise of the Patton Seamount, an undersea volcano near Kodiak, Alaska. A videotape of the discovery now resides in the hands of Brad Stevens, a biologist with the National Marine Fisheries Service in Kodiak. As the video plays on a television monitor, Stevens describes the nearly intact skeleton of a 40-foot whale.
STEVENS: "So here you see the skeleton. It's pretty good size. We're looking at the vertebrae here, which are probably a foot across, easily. There are a few things on it, but it's pretty well stripped clean. It's probably been down there a few years."
Its distinctly curved jawbone and skull identify the skeleton as having once belonged to a northern right whale. Right whales are extremely rare to see alive in the North Pacific Ocean; rarer still to find a complete skeleton lying virtually undisturbed on the seafloor. Stevens says the only thing missing from this skeleton was a single vertebra.
STEVENS: "Here's an interesting point in the skeleton. All of the vertebrae are here, shoulder blades and rib bones. Then there is a break in the spinal column, where it's missing a vertebra. So we go 50 meters off and leave the skeleton behind and what do we find? We find the missing vertebrae. It's a big bone. You wonder how the hell did it get over there? It didn't roll down hill. Something big had to pick that thing up and carry it over there, maybe a big shark. I have a vision in my mind of an army of crabs picking this thing up and carrying it across the seafloor, going 'Left, left, no, right. Ah, just drop it!'"
While finding a right whale skeleton on the seafloor is a stroke of luck, Stevens says it wouldn't be unusual to find other whale skeletons on the seafloor. In fact, he says dead whales drifting to the ocean floor are an important source of nutrients for a variety of sea life.
STEVENS: "It didn't come down as a skeleton. It came down as a whale. I mean, that's what happens when they die. They sink to the bottom. It becomes a food fall for all kinds of organisms around. There's a whole series of succession. First you get the mobile predators like large fishes and big crab that come in and eat, and then the less mobile predators like limpets and snails, and eventually you're down to microbes working on it. But there's a whole community of worms and things that crop up underneath it as the nutrients fall off and are redistributed into the sediment."
In the big scheme of the ocean food chain, whales—as big as they are—account for only a small share of the nutrients reaching the seafloor. The near-constant rain of plankton and other marine life together supply far more food than do dead whales. But the carcasses do help bring nutrients normally found only near the surface down into the deepest parts of the ocean. For creatures like the giant spider crab, a dead whale is a welcome feast.
STEVENS: "Some of the large crabs, like spider crabs, are living in places where there isn't much to eat. They can probably survive for long periods of time without eating. But they may subsist in large part off of food falls like this. It could be 100 of them or more that could live of a carcass like this for months."
OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider.
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Thanks to the following individual for help preparing this script:
Dr. Brad Stevens, Research Fisheries Biologist
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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