Genetic fingerprinting reveals natal origins of male leatherback turtles encountered in the Atlantic Ocean and Mediterranean Sea

This paper is not subject to U.S. copyright. The definitive version was published in Marine Biology 164 (2017): 181, doi:10.1007/s00227-017-3211-0.Understanding population dynamics in broadly distributed marine species with cryptic life history stages is challenging. Information on the population dynamics of sea turtles tends to be biased toward females, due to their accessibility for study on nesting beaches. Males are encountered only at sea; there is little information about their migratory routes, residence areas, foraging zones, and population boundaries. In particular, male leatherbacks (Dermochelys coriacea) are quite elusive; little is known about adult and juvenile male distribution or behavior. The at-sea distribution of male turtles from different breeding populations is not known. Here, 122 captured or stranded male leatherback turtles from the USA, Turkey, France, and Canada (collected 1997–2012) were assigned to one of nine Atlantic basin populations using genetic analysis with microsatellite DNA markers. We found that all turtles originated from western Atlantic nesting beaches (Trinidad 55%, French Guiana 31%, and Costa Rica 14%). Although genetic data for other Atlantic nesting populations were represented in the assignment analysis (St. Croix, Brazil, Florida, and Africa (west and south), none of the male leatherbacks included in this study were shown to originate from these populations. This was an unexpected result based on estimated source population sizes. One stranded turtle from Turkey was assigned to French Guiana, while others that were stranded in France were from Trinidad or French Guiana breeding populations. For 12 male leatherbacks in our dataset, natal origins determined from the genetic assignment tests were compared to published satellite and flipper tag information to provide evidence of natal homing for male leatherbacks, which corroborated our genetic findings. Our focused study on male leatherback natal origins provides information not previously known for this cryptic, but essential component of the breeding population. This method should provide a guideline for future studies, with the ultimate goal of improving management and conservation strategies for threatened and endangered species by taking the male component of the breeding population into account.Sample collection in Nova Scotia, Canada, was supported by funding from Canadian Wildlife Federation, Environment Canada, Fisheries and Oceans Canada, George Cedric Metcalf Foundation, Habitat Stewardship Program for Species at Risk, National Fish and Wildlife Foundation (USA), National Marine Fisheries Service (USA), Natural Sciences and Engineering Research Council of Canada, and World Wildlife Fund Canada. Funding for US samples was provided by National Oceanic and Atmospheric Administration, Massachusetts Division of Marine Fisheries, National Fish and Wildlife Foundation, and Cape Cod Commercial Fisherman’s Alliance. Funding support for this analysis and for Kelly R. Stewart was provided by a Lenfest Ocean Program Grant

Rapport d'activité 2020-2021 de l'Observatoire des Tortues Marines de France métropolitaine et de Saint-Pierre-et-Miquelon

Renewed under the Decree of December 30, 2020, the Marine Turtle Observatory of mainland France and St-Pierre-et-Miquelon consists of three Marine Turtle Networks: the Réseau Tortues Marines Atlantique Est (RTMAE) coordinated by the Centre d'Etudes et de Soins pour les Tortues Marines de l'Aquarium La Rochelle, the Réseau Tortues Marines de Méditerranée Française (RTMMF) coordinated by the Société Herpétologique de France and the Réseau Tortues Marines de St-Pierre-et-Miquelon, coordinated by the DTAM. The RTMAE has recorded 98 strandings/accidental captures/entanglements/opportunistic sightings at sea in 2020 and 68 in 2021. The RTMMF recorded 213 strandings/accidental captures/at-sea sightings in 2020, and 67 in 2021. The RTSPM recorded 13 opportunistic sightings at sea in 2021. Four species of sea turtle were observed in 2020 and 2021 on the coast of mainland France: Leatherback turtles (n=66), Loggerhead turtles (n=214), Kemp's ridleys (n=16) and Green turtles (n=3); in 2021, Loggerhead turtles (n=72), Leatherback turtles (n=54), Kemp's ridleys (n=3) and Green turtles (n=1). In Saint-Pierre-et-Miquelon, only Leatherback Turtles were observed. The temporal distribution of strandings recorded on the Channel-Atlantic coast shows a peak in January and February 2020, while in 2021 sightings took place mainly from October to December. On the Mediterranean coast, strandings were mainly recorded between April and August in 2020, and between February and August in 2021. Accidental captures/entanglements were observed throughout the year. On the Channel-Atlantic coast, the standard curved length of Leatherback turtles measured (n=22) averaged 140.6 cm. Loggerhead turtles measured (n=13) had an average curve length of 32.9 cm, while loggerhead turtles measured on the Mediterranean coast (n=65) had an average standard curve length of 52 cm. The main morbidity observed in the Channel-Atlantic region was hypothermia, and it was due to interactions with fishing activities in the Mediterranean.Renouvelé dans le cadre de l’arrêté du 30 décembre 2020, l’Observatoire des Tortues Marines de France métropolitaine et de St-Pierre-et-Miquelon consiste en trois Réseaux Tortues Marines : le Réseau Tortues Marines Atlantique Est (RTMAE) coordonné par le Centre d’Etudes et de Soins pour les Tortues Marines de l’Aquarium La Rochelle, le Réseau Tortues Marines de Méditerranée Française (RTMMF) coordonné par la Société Herpétologique de France et le Réseau Tortues Marines de St-Pierre-et-Miquelon, coordonné par la DTAM. Le RTMAE, a enregistré 98 échouages/captures accidentelles/enchevêtrements/observations opportunistes en mer en 2020 et 68 en 2021. Le RTMMF a récolté 213 échouages/captures accidentelles/observations en mer en 2020, et 67 en 2021. Le RTSPM a recensé 13 observations en mer opportunistes en 2021. Quatre espèces de tortues marines ont été observées en 2020 et en 2021 sur le littoral de France métropolitaine : Tortue luth (n=66), Tortue caouanne (n=214), Tortue de Kemp (n=16) et Tortue verte (n=3) ; En 2021, Tortues Caouannes (n=72), Tortues luth (n=54), Tortues de Kemp (n=3) et Tortues vertes (n=1). A Saint-Pierre-et-Miquelon, seules des Tortues Luth ont été observées. La distribution temporelle des échouages enregistrés sur la façade Manche-Atlantique permet d’observer un pic au mois de janvier et de février 2020, tandis qu’en 2021 les observations ont eu lieu principalement d’octobre à décembre. Sur la façade méditerranéenne, les échouages ont été majoritairement répertoriés entre les mois d’avril et d’août en 2020 et entre février et août en 2021. Les captures accidentelles/enchevêtrements ont été observées toute l’année. Sur la façade Manche-Atlantique, la longueur courbe standard des Tortues luth mesurées (n=22) est en moyenne de 140,6 cm. Les Tortues caouannes mesurées (n=13) avaient une longueur courbe de 32,9 cm en moyenne tandis que les Tortues caouannes mesurées sur la façade méditerranéenne (n=65) avaient une longueur courbe standard moyenne de 52 cm en moyenne. La morbidité principale observée en Manche-Atlantique est l’hypothermie et tient aux interactions avec les activités de pêche en Méditerranée

Toward a common approach for assessing the conservation status of marine turtle species within the european marine strategy framework directive

International audienceEnvironmental policies, including the European Marine Strategy Framework Directive (MSFD), generally rely on the measurement of indicators to assess the good environmental status (GES) and ensure the protection of marine ecosystems. However, depending on available scientific knowledge and monitoring programs in place, quantitative GES assessments are not always feasible. This is specifically the case for marine turtle species, which are listed under the Biodiversity Descriptor of the MSFD. Relying on an expert consultation, the goal of this study was to develop indicators and a common assessment approach to be employed by European Union Member States to evaluate the status of marine turtle populations in the frame of the MSFD. A dedicated international expert group was created to explore and test potential assessment approaches, in coherence with other environmental policies (i.e. Habitats Directive, OSPAR and Barcelona Conventions). Following a series of workshops, the group provided recommendations for the GES assessment of marine turtles. In particular, indicators and assessment methods were defined, setting a solid basis for future MSFD assessments. Although knowledge gaps remain, data requirements identified in this study will guide future data collection initiatives and inform monitoring programs implemented by EU Member States. Overall this study highlights the value of international collaboration for the conservation of vulnerable species, such as marine turtles

Marine turtle regional management units 2.0:an updated framework for conservation and research of wide-ranging megafauna species

Delineating spatial boundaries that accurately encompass complex, often cryptic, life histories of highly migratory marine megafauna can be a significant conservation challenge. For example, marine turtles range across vast ocean basins and coastal areas, thus complicating the evaluation of relative impacts of multiple overlapping threats and the creation of coherent conservation strategies. To address these challenges, spatially explicit ‘regional management units’ (RMUs) were developed in 2010 for all marine turtle species, globally. RMUs were intended to provide a consistent framework that organizes conspecific assemblages into units above the level of nesting rookeries and genetic stocks, but below the species level, within regional entities that may share demographic trajectories because they experience similar environmental conditions and other factors. From their initial conception, RMUs were intended to be periodically revised using new information about marine turtle distributions, life history, habitat use patterns, and population structure. Here, we describe the process used to update the 2010 RMU framework by incorporating newly published information and inputs from global marine turtle experts who are members of the IUCN Marine Turtle Specialist Group. A total of 48 RMUs for 6 of 7 marine turtle species and 166 distinct genetic stocks for all 7 species are presented herein. The updated RMU framework reflects a significant advance in knowledge of marine turtle biology and biogeo - graphy, and it provides improved clarity about the RMU concept and its potential applications. All RMU products have been made open access to support research and conservation initiatives worldwide.</p