Researchers on the tracks of turtles or sharks to protect them

Muse was in Nice on July 11, 2021, then headed to Barcelona before ending up near the Balearic Islands and staying off the coast of Egypt. This loggerhead turtle is now located, according to the latest data from December 9, 2022, between Sardinia and Sicily. She is one of the dozen turtles monitored using Argos telemetric beacons by the Natural History Museum from Paris for a year.

“We equip the animals at the end of their care, in the two centers with which we work in the Mediterranean, at Grau du Roi and in Antibes, specifies Françoise Claro, communication officer at the museum. The equipment is very small, designed and adapted to cause no inconvenience and it is efficient because the batteries can last several weeks or even months. »

Sharks also tracked in the Mediterranean

The aim of this program, which should last four years, is to know the routes that the turtles take, the areas where they prefer to stay and to deduce the places at high risk to better preserve the species. Françoise Claro details the first elements collected: “In total, we are studying six species, three of which are in the Mediterranean. They are threatened by human activities, collisions, degradation of their habitat and food. It is too early to draw conclusions, but we have already observed that the [tortue] Loggerhead enters and leaves through the Strait of Gibraltar, towards the United States or Cape Verde for example. »

Turtles are not the only animals tracked in the Mediterranean. From a decade, the Stellaris association placed nearly 40 sensors on blue sharks. “There is a large population in the Gulf of Lion, in the northwest of the Mediterranean, which is also a breeding area, specifies President François Poisson. We started to do this research because it is an endangered species and we had to act by recommending protective measures. There are currently no rules. »

The association has created a good practice guide for fishermen to handle and release endangered species and thus maximize their survival. “The blue shark is one of the most caught because it is present everywhere”, adds the founder of the association. There is already international cooperation with countries bordering the Mediterranean. “We were the last to adopt this research but we are all working together to reduce bycatch and have legislation on the species. »

Strategies for taking action

International cooperation is therefore essential for the protection of marine species. Damien Chevallier knows it. He has been working there for twelve years with the National Center for Scientific Research (CNRS) for turtles, in the Atlantic this time. “Without the tags, we would never have been able to say and imagine that the turtles that are in Florida are the same ones that were in Venezuela before and that were born in Guyana,” he says.

For him, the interest of these programs is already concrete. “The monitoring, launched 40 years ago, shows that egg-laying in Guyana is in decline. We have gone from 50,000 clutches per season of leatherback turtles to less than 70 clutches today, exclaims the researcher. Argos beacons have made it possible to identify the factors of this phenomenon. By combining with other technological tools such as biologgers, we are now developing targeted strategies to act. The researcher cites the creation of hatcheries “on an international scale” in response to the increase in erosion, accentuated by water pollution, which destroys 20% of turtle nests. With his teams, he has also ensured that specific places in Martinique are no longer frequented by tourists during certain times to prevent their activity from being harmful, without an entire region being penalized.

He concludes: “Turtles are endangered and develop responses to environmental stress. Everything that is tracked comes from a desire for conservation and you can’t protect if you don’t know the biology. Now we must act. And we need a real sea policy from the public authorities with human resources and greater monitoring to fight against the degradation of biodiversity. »

sea ​​elephants, better than a boat or an ocean robot »

For several years now, turtles have not been the only species observed by researchers. The MEOP Consortium, which brings together Franco-Australian teams, has placed beacons on elephant seals in Antarctica. Lia Siegelman, a postdoctoral fellow at the Scripps Institution of Oceanography, did a thesis on these programs. “These animals are very good swimmers and have access to areas under the ice floes, unreachable for humans,” she explains. They bring back valuable data for understanding vortex dynamics. Thus, the elephant seals make it possible to know how the ocean is affected by melting, for example. »

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