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Saturday, October 16, 2010

A Miner's Canary

Why should we care about one little wading bird going extinct?

Why shouldn't we care? I'm of the viewpoint that every species on this planet has just as much a right to live as humans do. Why does a species have to be somehow "special" or "useful" before we deem it important enough to have a right to be here? No, the Redknot isn't large and majestic like the eagle, nor is it "useful" to human hunters as are gamebirds. It's not flashy nor does it have the melodious song of a warbler. It's just a wading bird - a wading bird that happens to migrate up to 20,000 miles in a single year, from South America to the Arctic and back again.

The Redknots' journey is the clue to the answer to my first question - why should we care?

On its northward migration during the northern hemisphere's spring, the Redknot undertakes some incredible, non-stop, sea-crossing flights. There is no snack service, no stopovers, no beverage cart, no RADAR to avoid bad weather. They fly, completely of their own power, for as long as it takes to reach their destination. Some don't complete the crossing - they didn't get enough to eat before the journey so they perished along the way. Each Redknot has to build up a sizeable fat reserve in order to power those wings for the flight - no fat, no safe landfall.

The two major non-stop legs for the Redknot over the ocean are from South America to the Atlantic shores of the USA, and from there up to the Canadian Arctic. Once the Redknots reach the shores of the USA, they must turn into eating machines in order to make the second leg of the trip up to the Arctic. Their fat reserves depleted, the Redknots set about gobbling up their main food source - the eggs of Horseshoe Crabs. You see, the Redknots' landing in the USA is incredibly timed to coincide with the spawning of the Horseshoe Crabs along the Atlantic Coast. The little travelering birds, along with many other species of shorebirds, are almost totally dependent on the eggs of the crab in order to make their journey to the Arctic, alive.

And therein lies the rub.

Humans have been, and continue, to decimate the Horseshoe Crab population. We seem to be of the mindset that since they've been around hundreds of millions of years, that they will survive no matter what we do to them.

Unfortunately that's not the case. The Horseshoe Crab was ancient well before the dinosaurs began to evolve. It's survived many mass extinctions, but it's now being decimated by humans.


Because we humans seem to have a lust for eating eels and conchs. You see, the Horseshoe Crab is being slaughtered by the millions to become bait for eel and conch fishing. From the late 1980s to 2004, the annual Horseshoe Crab harvest increased from 500,000 pounds per year to 5 to 7 million pounds per year. Scientific surveying has shown a 90% decline in Horseshoe Crab populations from 1990 to 2004.

Not surprisingly during this same time period, Redknot numbers plummeted from over 100,000 individuals to about 13,000. Latest estimates put that number well below 10,000 - perhaps too small for the species to survive.

It was the plummeting of the Redknot populations that keyed scientists in to the plight of the Horseshoe Crab. The crab population plummeted, so there weren't as many crabs to lay eggs and therefore, far fewer eggs for the Redknots to eat on their migration. Fewer eggs to eat meant that more Redknots perish before they reach their breeding grounds in the Arctic. What we have is a negative feedback loop.

Why should we care about one species of crab?

Horseshoe Crabs are vital to human health.

Currently, the medical industry uses a part of the blood of Horseshoe Crabs to test all injectible medications and devices for bacterial contamination. If you have received a vaccine (like the flu vaccine) or an injectible or IV drug (such as an IV antibiotic), you owe your health to the Horseshoe Crab. Other medical uses for Horseshoe Crab blood are in the works, including possible cancer treatments, anti-virals, anti-fungals, and antibiotics. In order to obtain this extract, Horsesheoe crabs are captured, bled, and released. Most survive to breed, some do not. Crab deaths from being bled are estimated to be from 2-15%. Still, much better than the 100% mortality rate of those caught to become bait.

Now are you concerned by the drop in Horseshoe Crab numbers? You should be. We have no other reliable way to test for bacterial contamination in our vaccines and injectible drugs than with the derivative of the Horseshoe Crab's blood.

So, the Redknot was, in a sense, the miner's canary. It's population crash alerted us to the crash in Horseshoe Crab numbers. It's also a wake-up call - we can't continue to decimate crab populations without putting ourselves in danger.

It's not too late to act - what we can do about this is the subject of my next post.

This post Copyright 2010, Nancy Rynes. No portion of this post may be reproduced in any form without express written consent of Nancy Rynes.

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