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The pantropical spotted dolphin (PSD, Stenella attenuata) is the most common cetacean species observed within the Agoa Sanctuary, located in the Lesser Antilles, Eastern Caribbean. These dolphins are easily observable and are the main target of whale-watching activities along the leeward coasts of Guadeloupe and Martinique islands. Because PSD is common within the sanctuary it is considered a resident species, however, no research has been carried out to estimate its population status and movement patterns between islands. Previous unpublished work found the sighting of an individual in Martinique and Guadeloupe, suggesting potential exchange of individuals between these islands. To test this hypothesis a photo-ID survey in 2018 and 2019 was conducted, resulting in 54,298 photographs. With no matches of individuals between islands, our findings do not support regular exchange of PSD individuals between Martinique and Guadeloupe. However, given previous re-sighting data, it is possible that movement of individuals between islands exists but at lower frequencies than expected, which can only be detected through long-term surveys. Additionally, populations from both islands showed relatively high site fidelity. We found that in Guadeloupe the PSD population is homogeneously distributed along the coast. In contrast, in Martinique the PSD population was composed of two resident groups concentrated in one area. Moreover, 70 new individuals were identified in Guadeloupe and 54 in Martinique while POPAN modelling estimated the number of marked individuals in the study area during 2018 and 2019 at 89 in Guadeloupe and 90 in Martinique. This research provides the first insights on the residency and movement patterns of S. attenuata in the Agoa Sanctuary and can inform future efforts in management and conservation.

Although human activities are developing in French Guiana Exclusive Economic Zone (EEZ) and surrounding countries, knowledge on diversity and ecology of cetaceans in the region is scarce. This study aimed to collect new information on the cetacean species occurring year-round in the entire French Guiana EEZ by combining visual and acoustic data obtained from three boat-based campaigns conducted by local NGOs. The GEPOG campaign was conducted from July 2011 to June 2012, four days every two months; the COHABYS campaign was performed five days per month from January to May 2018; the OSL campaign consisted in four 10-day surveys conducted in June, July, September and October 2018. The visual observation effort conducted when Beaufort sea state < 5 was 1,961 km, 1,491 km and 3,243 km respectively. Acoustic records were done when Beaufort sea state < 5 during daylight and/or nighttime, depending on the survey. A total of 132 cetacean sightings were done. Five cetacean families and 15 species were identified. Delphinidae was the family most frequently sighted (91% to 100% of groups and 99% to 100% of individuals per campaign). The most frequent species in the area were identified, along with their distribution and phenology: Guiana dolphin (Sotalia guianensis) was found in the coastal area (0-20 m), the long-beaked common dolphin (Delphinus delphis) was sighted on the shelf (20-100 m), along with the bottlenose dolphin (Tursiops truncatus) and the Atlantic spotted dolphin (Stenella frontalis) that were also common on the upper slope (100-1,500 m). Finally, the spinner dolphin (Stenella longirostris), the melon-headed whale (Peponocephala electra) and the pantropical spotted dolphin (Stenella attenuata) were frequent on the slope (100-3,500 m). The results suggest these species may be found in French Guiana waters all year round and mother and calf pairs, as indicator of reproduction, were observed for all of them except the long-beaked common dolphin and the Guiana dolphin. Mother and calf pairs of humpback whales (Megaptera novaeangliae), that potentially belong to the “A” stock, were also sighted twice, as well as two groups of sperm whales (Physeter macrocephalus) with calves. Hence, these results showed that French Guiana bears a particular responsibility for the conservation of cetacean biodiversity, but a lot remains to be done to strengthen knowledge and conservation of these species in the territory.

Chez la Tortue verte (Chelonia mydas (Linnaeus, 1758)), la plupart des estimations d’abondance reposent sur une phase du cycle, la nidification. Or, le suivi des tendances démographiques chez les juvéniles s’avère essentiel pour mettre en œuvre des mesures de gestion précoces. Dans cette étude, nous avons effectué une estimation de l’abondance des Tortues vertes juvéniles présentes le long de la côte Caraïbe en Martinique. Les données ont été récoltées sur six mois (de janvier à juillet 2019), sur la base du modèle capture-marquage-recapture par photo-identification. Nous avons d’abord estimé l’abondance pour chaque anse prospectée (n = 17) après avoir caractérisé leur population à l’aide du logiciel Close-Test. En fonction des analyses, les modèles de Schnabel, Schumacher-Eschmeyer, Lincoln-Peterson ou Jolly-Seber ont été utilisés. Nous en avons ensuite déduit l’abondance pour l’ensemble de l’île, estimée à 150 tortues [93-396] avec une forte fidélité de ces dernières aux sites d’alimentation. La taille des individus a également été notée et des tendances sur la répartition des individus ont été mises en évidence.