Marine distribution of Lepidochelys olivacea along the Pacific coast of Nicaragua outside the breeding season

Géraldine Dina S Mertens, Marc Kochzius, Joëlle De Weerdt

Onderzoeksoutput: Poster


— Olive Ridley turtles (Lepidochelys olivacea) are classified as vulnerable in the International
Union for Conservation of Nature IUCN Red List of Threatened Species (Abreu-Grobois 2008) and are known to migrate between breeding and foraging sites (Da Villa 2011). Most research studies and conservation efforts focus on nesting beaches, but coastal distribution and habitat use patterns have been poorly investigated (Peavey 2017). It is unclear where sea turtles foraging sites are located and how their distribution overlaps with
anthropogenic activities, especially with the fisheries. Nicaragua is a known breeding area for Olive Ridley turtles, but little is known on the ecology and marine distribution of the species. This study aims to identify hotspots outside the breeding season and critical habitats to ensure effective and successful management plans
for the recovery of Olive Ridley turtles.
To reach this objective, sightings of turtles were opportunistically collected on boat-based surveys initially planned for cetacean research expeditions along the Pacific coast of Nicaragua. Two study sites were considered: Padre Ramos (north-western site) that is pristine compared to the second site San Juan del Sur that is facing coastal anthropogenic pressure (south-western site). Expeditions took place between January and April from 2016 until 2020 (except 2019), outside the breeding season. Whenever a turtle species was encountered, the number of individuals, their behaviour (surfacing, swimming, mating), gender, time, date and the geographic position were gathered. In addition, the presence of boats was assessed every 30 minutes during survey.
The Kernel Density Estimation algorithm was used in the GIS software to generate maps of marine hotspots of Olive Ridley turtles. Our preliminary results show that turtle occurrence vary between sites. Two hotspots were
identified; one in the north further away from the coast and one in the south located closely to a beach known for hosting particular mass-nesting events of Olive Ridleys. Increasing knowledge of turtle distribution will contribute to the efficiency of conservation measures inthe future. Our research will further investigate the influence of environmental parameters on their distribution patterns and verify whether they overlap with fishing activities, which will give important information for decision makers to reconsider the size of their marine protected areas.
Originele taal-2English
StatusPublished - 15 dec 2020
EvenementYoung Researchers Overseas’ Days - Royal Academy of Overseas Sciences, Brussels, Belgium
Duur: 15 dec 202015 dec 2020


ConferenceYoung Researchers Overseas’ Days
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