Monthly Archives: January 2013

Week 15: A comparison

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It is cold today in Halifax- really cold. The current temperature is around -23 C with the wind-chill, and is expected to fall to -29 C tonight. All of us who have to brave freezing cold temperatures this week in Canada and the US Northeast and Midwest are likely a little envious of Inspire, Lily Rose, and Red Rocket’s current position.
As a comparison, the water temperature in Halifax Harbour is currently 4 C, with a freezing spray warning in effect. The surface temperature of the Caribbean Sea today? A lovely 27 C!

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Mignonette is gone

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So the speedy Madame Mignonette, who looked for some time like she was going to be the turtle to beat, is no longer transmitting.

Not to worry, however. Dr. Mike James has been tracking leatherbacks in Canada since 1999, and he has seen this happen before. He is not concerned that Mignonette is hurt. Although we are hopeful that any satellite tags we put out will last until the turtles reach the nesting grounds, there is never a guarantee.

Satellite tags stop working for a number of reasons. The antenna can be damaged or can break off. The links holding the tag to the turtle can break. The batteries powering the tag can run out. Or, epibionts (organisms that live on other organisms), like barnacles, can colonize on the tag. This is called “biofouling.” Biofouling is a problem because it prevents the salt-water switch on the tag from drying out properly. When the salt-water switch is dry (which normally happens when the turtle is at the surface of the water), the satellite tag transmits data. If the switch isn’t dry, or if it is covered, the data is not transmitted.

Now, if we look at Mignonette’s case specifically, our best guess is that either her antenna is broken or the tag has fallen off.  The last reading we had from her tag showed that the batteries were still strong. We use anti-fouling paint on our transmitters to control biofouling. That doesn’t mean it can’t happen, but it wouldn’t normally happen so soon.

But—and there is often a “but” when it comes to sea turtles—don’t count Mignonette out altogether. She has a microchip in her shoulder muscle (called a “PIT”) and small metal tags on her rear flippers that identify her as a Canadian turtle. So when she hauls up on a nesting beach, our research partners in the south may find her. And if her transmitter is still on, they will take it off and send it back to us.

Or maybe, unaccountably, Mignonette’s satellite tag will just start transmitting again. That has happened, too.

Stay tuned.

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Inspire

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The turtles are turning in toward the mating and nesting grounds. Even Esmerelda, who was just about 750 km from Cape Verde off the coast of west Africa, has started to head slightly west. I expect Trekker to follow suit soon. (Riley is, of course, being Riley and doing her own thing off the continental U.S.!)

Jan8map_v2_zoom_InspireBut it’s Inspire I’m particularly interested in today because she illustrates something important. If you look at the close-up of her track, you’ll see what I’m talking about. In just 15 days, she has crossed through the waters of five nations: France (the islands of Guadeloupe and Martinique), Dominica, St. Lucia, St. Vincent and the Grenadines, and Grenada.

Leatherbacks are what we call a “highly” migratory species. Their migrations are immense. This in itself is wondrous. How do the turtles find their way? But migrations of this extent present complications. What happens when an animal that is protected in one country (like Canada) swims into the waters of another country whose interest in protecting it may be different? How can we be certain that our work to keep endangered leatherbacks safe in Canadian waters is upheld in France, Dominica, St. Lucia, St. Vincent, Grenada, and in the many other countries whose waters “our” turtles inhabit?

One way is if the countries agree to work together—a tall order under any circumstances. Back in 1994 nations in the western hemisphere began to talk about how they could best conserve sea turtles in the Americas. What came of those discussions is a treaty called the Inter-American Convention for the Protection and Conservation of Sea Turtles.

Fifteen countries have signed it.

But not Canada. And that bothers me.

As Inspire swims through those political boundaries, I’m reminded of the importance of international cooperation. I think Canadians should be leaders here. I think leatherbacks, making these incredible journeys, deserve our support.

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