Monday, February 28, 2011

Krill, the wonder food

Do you know about krill?  Before my trip to Antarctica, I guess I knew the word and sort of what it meant -- tiny fish that are eaten by whales, seals, etc.  But now that I have seen them in real life, I am terribly impressed by those little critters.

Krill are little shrimp-like sea creatures that constitute probably the largest animal species on the planet, by weight.  Supposedly huge populations of krill have been visible from space.  They eat plankton and in turn are eaten by all kinds of larger species.  It's not surprising that small- and medium-sized birds and animals eat these tasty seafood treats, but it is surprising that some of the biggest creatures in the world, whales, subsist on krill too.

Here are krill in the wild.  Actually, these krill have already been partially processed, by penguins.  On one of the rocky Antarctic beaches we visited, these krill were lying around in little piles.  One of the naturalists explained that this was a sign of good times for the gentoo penguins who were nesting on this beach.

They were apparently so well supplied with food that when they went into the ocean to catch krill for their chicks, they were able to fill their craws to overflowing.  As they returned to shore, the slightest bump on the tummy would cause the krill to be regurgitated out onto the beach.

If krill are such delicacies for birds and animals, it's no surprise that people might want in on the deal.  Krill are nutritious (almost half of their weight is protein) and the naturalists told us that there's nothing more delicious than a couple of handfuls fried up in a pan over a campfire.  But they have to be eaten quickly, because they will start to decompose in a couple of hours, and they have to be peeled because their skeletons are high in toxic fluorides.  So commercial fishing of krill is limited to fish food, for aquariums and aquaculture (fish farms).

Guess what -- krill are in danger, from global warming (because they eat the algae that live on the bottom of the pack ice, which is melting) and from rising acid levels in the ocean (because of more carbon dioxide in the atmosphere, thanks to burning of fossil fuels).  We all know what happens when you start to mess with the most abundant and essential element in a food chain, and it looks like we're doing it again.

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