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Wednesday, March 30, 2011

What do three sablefish do over the course of 20 years? Grow a few inches, move around a bit...probably go bowling a few times

This is pretty cool:

From the Southwest Fisheries Science Center, we learn that fishermen on the U.S. west coast have recently caught several sablefish (aka black cod) that were tagged years ago in a now-defunct tagging program. Each of the three sablefish in question was first tagged over 20 years ago. Two were recovered more than 500 miles from the point of tagging,  but the third was found less than 15 miles from its tagging location.

But the really interesting thing is how little these fish grew over that span of time: from starting lengths of 18-20 inches, each fish added only 3-4 inches in length, for an average annual growth of less than one quarter of an inch.

OK, growth rates of less than a quarter-inch per year...I'm checking with my joke calculator to see how to handle this's telling me to say something about "the Tom Cruise of the fish world"...nah, that's too easy.

But still, think about it: for 20 years, these three fish kept on keepin' on, doing their thing over soft substrate, avoiding all manner of peril in the process. That's impressive - 20 years is a long time. 20 years ago, I was still building tree forts and stocking them with Fruit Roll-Ups.

To a sablefish, though, 20 years really isn't all that much: they are thought to live up to, and possibly beyond, 90 years. 90 years in the wild. Meditate on that, o ye who couldn't survive two nights' camping without a Thermarest.

Don't know much about sablefish? Don't beat yourself up too much, friend. Sablefish are important commercial species but seem to fly under the public's radar a bit. Perhaps that's because most of B.C.'s sablefish catch goes to markets in Japan. Whatever the reason, sablefish do seem to be somewhat overshadowed by the more well-known commercial fish - your salmon, your halibut, your rockfish, and so on. That's a shame, because the B.C. sablefish fishery is in good shape. It's received a green ranking from SeaChoice, and has also been certified by the Marine Stewardship Council.

So to shed  more light on the species, I'm going to tell the story of sablefish, starting at the species' origin many millenia ago and progressing century-by-century through the ages. This story will be narrated in the first person, from the perspective, and in what I imagine is the dialect, of a sablefish named Stevie Sablefish and...wait, what's that?

Instead of reading about sablefish, you'd rather just watch a clip of a sablefish trying and failing to eat a sea cucumber?

OK, that we can do.

(This video is from Living Oceans Society's Finding Coral Expedition, and that delighted voice you hear on the dive video belongs to one Michael Reuscher. Michael is a Ph.D. student, polychaete devotee, and all-around good guy. He gives a detailed account of his submarine adventures during the Expedition in a blog post over at Deep Sea News).  

Also - thanks to LOS' Will Soltau for the original sablefish article. Good find Will!

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