To promote the conservation of seagrass beds and related marine plant species

To promote the conservation of seagrass beds and related marine plant species

To promote the conservation of seagrass beds and related marine plant species

Compagnonnage entre réserves
Compagnonnage entre réserves

Since 2007, the Réserve Naturelle has done an annual scientific study of the reefs and plant beds. This took place this year on September 9-12, with the support of a staff member from the Réserve Guadeloupéenne de Petite-Terre. He came to help the staff in Saint Martin document the evolution and state of these coral and sea plant communities, at stations inside and outside of the Réserve. As usual, this kind of collaboration will see the staff from Saint Martin similarly lend a hand in Saint Barth and Petite-Terre. This year, this ongoing study was augmented by a study of groupers, as part of the LIFE program, at four of the eight sites visited. These sites will also be the object of a bi-annual study throughout the LIFE program, until 2023

Algues vertes dans l’herbier – Green algae in the seagrass © Julien Chalifour
Algues vertes dans l’herbier – Green algae in the seagrass © Julien Chalifour

Organized every year since 2008, this year’s Reef Check took place on September 17-19, off the coast of Galion, Caye Verte, Pinel, and Rocher Créole. Two volunteers, Théo Feger and Guillaume —of Jorakhae Free Diving School — joined forces with the Réserve. The data is still being evaluated but, one year after hurricane Irma, observation revealed a high presence of green filamentous algae, especially on coral reefs and plant beds, but also washed up on the beaches, including Pinel. These algae are generally present in these areas, but usually on a seasonal basis and of a smaller quantity. Their abundance this year is an indication of organic coastal pollution, with water treatment stations at but 50% of their capacity, according to a press release issued by the EEASM in October 2018. The proliferation of these algae is promoted by strong rains, at which time runoff water is filled with organic materials and nutrients, and this year also from non-purified wastewater. Consequently, the soil leaching and coastal pollution enrich the shoreline milieu, which benefits the algae, but to the detriment of the coral that suffocates. The degraded quality of the coastal waters represents the first cause of deterioration of the marine biodiversity in Saint Martin.

© Julien Chalifour
© Julien Chalifour

Since 2007, the Réserve Naturelle has continued its annual scientific study of the reefs and plant beds. This took place this year on September 24-26, with the support of Jonas Hochart, from Saint Barth’s Territorial Environmental Agency. He helped the team from Saint Martin in documenting the evolution and general state of the coral communities and plant beds on the three reef stations— Chico, Rocher Pélican, and Fish Pot, a site located outside of the Réserve —and the three plant bed stations — Rocher Créole, Pinel, and Grand-Case, this last site also outside of the Réserve. The data is under evaluation, but the divers reported the return of sponges, which were heavily impacted by hurricane Irma. They also noted an excessive presence of dead coral colonies, also due to Irma. On the other hand they observed green algae, as well as the return of young macro-algae, which had drastically regressed due to the effects of successive swells. These algae compete for space and light with the coral, and clearly benefitted from the wastewater thrown into the sea.

Under the aegis of joint underwater projects between reserves, Julien Chalifour went to lend a hand in Saint Barth in an identical context, but this time for the reef stations at Boeuf islet and near Colombier. He also participated in the implantation of a new plantbed station in Petit-Cul-de-Sac, since the historic station in Marigot Bay disappeared due to private cutting of vegetation, which provoked soil leaching and subsequently the suffocation of plant beds. Participation in a study organized by the Réserve of Petite Terre in Guadeloupe followed shortly thereafter.
Une raie dans l’herbier - A ray in the seagrass © Julien Chalifour
Une raie dans l’herbier - A ray in the seagrass © Julien Chalifour

One year after her first mission in the waters of Saint Martin, Fanny Kerninon returned to the island last May. Working with the Réserve, this scientist/diver visited four plant bed stations: Grand-Case, Rocher Créole, Galion, and Tintamare. Working on her thesis at the University of Western Brittany, and in collaboration with IFRECOR, for which she coordinates the observation of underwater plant beds for Overseas France, this young woman dives into tropical waters the world over, from the Caribbean Sea to the Indian Ocean. Her goal is to produce a “tool box” for the study of plant beds and the indicators that allow managers to follow the health status of “their” plant beds, which are very different one from the next. The challenge for Fanny is to develop a set of standard tools that can be used to study all types of underwater plant beds. She also represented Overseas France at the World Seagrass Conference, June 11- 17, 2018 in Singapore.

Did You Know?
Saint Martin is one of the major overseas sites where the study of plant beds has already been in place for 10 years. The Réserve Naturelle is one of the initiators of this collaborative study, which is considered to be very comprehensive by the scientists who are familiar with it.
Une tortue verte sur Halophila - Green turtle on Halophila © Julien Chalifour
Une tortue verte sur Halophila - Green turtle on Halophila © Julien Chalifour

A team of American scientists from Florida International University (FIU), including Dr. Jeremy Kizska, spent time with the Réserve as part of their regional mission. On June 18- 22, 2018 in Tintamare’s Baie Blanche, green turtles were the focus of research designed to better understand their relationship with the plant beds currently colonized by Halophila stipulacea sea grass. This invasive species was introduced via anchors and ballast water from boats, and little by little gobbled up space in the underwater plant beds, where it is now in competition with two native species: Syringodium and Thalassia. The scientists observed the location of these underwater reptiles throughout the day, as well as their activities, as they tried to identify the different algae on their menu. This study will also allow for an estimation of the size of the turtle population that visits the plant beds in Baie Blanche, and if it was impacted by Irma. The first data reported by the Réserve was that they have not found any animal cadavers at the site. The data that still needs to be thoroughly analyzed seems to mark a major change in the habits of the sea turtles in Guadeloupe, as in Saint Martin, following Irma and the other meteorological events that took place in late 2017. This study should have also allowed for the taking of skin samples into order to open the door for the first local look at Fibropapillomatosis, a herpes virus that affects certain sea turtles around the world, and the factors that trigger the risk of this disease that scientists are just beginning to understand.

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