Tag Archives: biofouling

Beverly

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It’s generally the time of year that we start to get very excited about our turtles heading to the nesting beach.

I had been, as you know, particularly curious about what Beverly was going to do. Beverly has been one of our most interesting leatherbacks. She has a nesting history in Trinidad that suggested she should have nested there last year. But as you may remember, she didn’t. Instead, she slowly looped eastward.

You can see from the map below that Beverly went south this year. Part of me was glad in that I-told-you-so kind of way. She’s doing what she’s supposed to do, is how I felt. She’s doing the thing that fits my human, scientific-box-of-a-Beverly.

I settled back, excited to follow her to the nesting beach at Matura.

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But then her transmitter stopped working. There are a number of reasons this might happen, but in this case, we think the cause was biofouling—when organisims like barnacles or algae grow on the satellite tag and prevent it from working properly.

So we have to wait to see what will happen next. Hopefully, our friends at Matura Beach in Trinidad will find her nesting there this year as she has in the past. They’ll recognize her either from the transmitter (if it hasn’t fallen off) or from her flipper tags.

Or maybe she’ll haul up on an isolated stretch of beach in Trinidad, where no one finds her and we have to wait for many years and many more nests to hear from her again.

The scientific part of me wants her to be found in the next few weeks. The part of me that likes happy endings wants this, too. The loop closed—from Canada to the Caribbean—feeding to nesting. A safe journey from one “home” to the other.

But then I remember, a few years ago, standing on Matura nesting beach myself in the dark night. The loud wind blowing clouds across the bright moon like dried fall leaves. The turtles hauling up out of the surf around me, slowly making their laboured way up the sand to lay their eggs as their species has done for millions of years. For millions of years.

And there is something I love about the idea of Beverly doing this away from our human eyes. Alone. Wild. It seems just like her.

 

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Transmission trouble

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Beverly is still way north and east of where we’d expect to see her. She’s only about 330 km from the Azores! Christie is just where we’d expect her—about 1,600 km from Trinidad, where she should be heading to nest in the next few months.

And then there is Asha. You can see that we haven’t had a good hit from her satellite tag since last week. We’re not getting any satellite locations from her tag, although the tag is still trying to communicate.

In order to get a location, the satellite must receive approximately four messages from the tag when it passes over. It takes that much information to verify where the tag is. Right now, it seems as though Asha’s tag is sending only one message at a time. We haven’t determined why quite yet, though we suspect the tag might have biofouling issues. Biofouling is when organisms like algae and barnacles colonize on the tag and impact its performance.

Although frustrating, this isn’t unusual. You may remember a similar situation with Jacquelyn and the remarkable story of Red Rockette!

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The beeline

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Today there is good news and not-so-good news about Margaret.

The good news is that she is making a beeline for the nesting beaches of Trinidad. Check out this map.

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She left coastal Barbados three days ago, and look at how close she is to Trinidad already! The nesting season has already started there, although peak season is still about two months away.

2014_02_27_Map_TrinidadIn the Atlantic, mature female leatherback turtles do not nest every year. They nest every two or three years. During their nesting years, they will generally lay around eight nests, about 10 days apart. In 2011, Margaret was recorded nesting both at Matura and Grande Riviere beaches in Trinidad. We’ve contacted our colleagues who work on those beaches, and we will continue to keep them posted about Margaret’s location. We hope that they will find her when she nests and remove her valuable transmitter so we can deploy it on another leatherback in Canada.

The not-so-good news is that the quality of the locations we’ve received from Margaret’s transmitter over the past few days has not been good. I yelled “No!” out loud this morning when Devan, our turtle technician, told me that the last series of locations were  “B” class. B-class locations are the poorest quality, and generally indicate that only two tag transmissions were received by the satellite to calculate the turtle’s position. The more transmissions the satellite receives, the better its estimate of the turtle’s location.

A long series of B location estimates—especially over several days—can mean the turtle is spending very little time at the surface of the water. It can also mean that the tag is running low on battery power or has started to “biofoul.” Biofouling is when organisms like algae and barnacles colonize on the tag. This can negatively impact the tag’s performance.

This may mean that we will lose transmissions from Margaret’s transmitter altogether—even before she makes it to the nesting beach. (You may remember this is what happened with Jacquelyn.) It doesn’t mean, however, that someone won’t find Margaret on the beach anyway. Last year, dedicated beach workers in Colombia found our turtle Red Rockette after her transmitter had stopped working. It’s just a lot harder to do.

I hate when this happens just when the animals are so close to nesting! But at least we know where Margaret is heading. Stay tuned…

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Jacquelyn?

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Our turtles’ tracks are no longer hugging tightly to one another. Instead, you can see Miss Margaret making her way toward the nesting beaches. We know that she has nested in Trinidad before, so we ultimately expect to see her land there.

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You’ll note that the last date for Jacquelyn’s track is January 5. This is because we haven’t had a good quality location from her transmitter since then. We’ve had some poor quality locations over the last few days and have heard nothing yet today.

We aren’t worried that something has happened to Jacquelyn herself at this point. We suspect instead that there may be epibionts (organisms, like barnacles or algae, that live on other organisms) growing on her satellite tag, preventing it from working properly.

When this happens, we say that the tag is “biofouled.” 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.

We’ll have to wait and see what happens over the next week or two.

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