Where the green turtles are

(originally posted 7 June 2011 on Conservation International’s blog)

For the past few decades, turtles have not been alone on their tropical nesting beaches around the world. They now share many of these beaches with humans: some who eat turtle eggs (or turtles), some who build hotels, condos and beachfront homes, and others who just want to soak up the sun.

But there is another group of humans spending lots of time on turtle beaches with a different goal in mind: counting turtles.

These turtle counters use any means necessary to perform their censuses. Some use small planes to fly low over beaches and count turtle tracks from the air. Some cruise coastlines in boats. Some even count while on horseback. And some do it the old-fashioned way: boots (or bare feet) in the sand, walking miles of beach.

Although sauntering sandy tropical beaches while the surf rolls underfoot might sound idyllic, I can tell you that it is not for the soft of foot. I worked with many volunteers unaccustomed to the physical toil of beach patrolling whose feet paid the price in blisters and bandages.

Despite the hardships, walking where land meets sea in search of prehistoric reptiles for endless hours under starlit skies is simply magical. We would lie on our backs during breaks, catching our breath, swigging water, and counting shooting stars that would brighten the sky like a glimpse of daytime.

But nothing — I mean nothing — compared to witnessing a turtle emerging from the water. The monotony of the breaking and receding surf would give way subtly to a large, black shape, slowly plodding from the water toward the dry sand ahead. We would wait breathlessly for her to haul her massive body out of the ocean and commence the ancient ritual of reproduction. While each nesting event is unique, the telltale track carved into the wet sand by the flippers of a nesting sea turtle is the mark counted by turtle census workers around the world that together provide enough information to assess turtle nesting populations.

With so many beaches, and so many people around the world trying to count turtles, it’s hard to get a global perspective from all of these separate censuses. So just like the population censuses that national governments conduct every decade, we started the State of the World’s Sea Turtles (SWOT) initiative — a partnership between Conservation International, Duke University, and the IUCN Marine Turtle Specialist Group — to compile local censuses contributed by hundreds of researchers to provide the first comprehensive global view of sea turtle nesting around the world.

In the most recent SWOT Report, we compiled nesting data from more than 1,000 nesting sites worldwide for the green sea turtle (Chelonia mydas) and published the most detailed map of green turtle nesting ever created. Download the map here (PDF – 8.91 MB)

The map shows how widespread green turtle nesting is, with nesting sites circling the globe’s midsection and extending throughout tropical latitudes. Nesting sites range from a handful of turtles a year to the tens of thousands of nesting females annually nesting at places like Raine Island, Australia, and Tortuguero, Costa Rica.

A striking feature of this map is that green turtle nesting is viewable at multiple scales: while the global view shows the dizzying multitude of nesting sites worldwide, three dozen inset maps allow the viewer to zoom in to more local geographies. These close-up views show the incredible diversity of places where green turtles are, from island archipelagoes in the central Pacific Ocean to mainland beaches on major continents. This means that to protect turtles throughout their nesting range, different strategies need to be developed depending on geography.

Also, by presenting available census data from all around the world, the SWOT maps show areas of high coverage (where there’s lots of turtle counting going on) and areas towards which more efforts could be directed.

Turtle researchers aren’t the only ones who understand the importance of the SWOT maps. Recently, the global green turtle map — and mapper Andrew DiMatteo — won the International Conservation Mapping Award, given by Esri, the world’s leading provider of geographic information systems (GIS) software services.

This prestigious award shows not only the high quality of the map products SWOT produces, but also recognizes the importance of data-sharing and collaboration among colleagues from all corners of the world for improving shared knowledge and prioritizing conservation work across many geographies.

As long those turtle-counting humans continue their beach-to-beach censuses, SWOT will continue to put turtles (and their counters) on the map.

(Click to download the award-winning map (PDF – 8.91 MB))

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