Turtle Populations Research Articles

Global and regional patterns in distribution and threat status of zoo collections of turtles and tortoises

Turtles are a globally threatened group of reptiles. Zoo populations may contribute to the conservation of species, including turtles, but collection composition may not align with conservation needs. We combined data from the Zoological Information Management System (ZIMS), EDGE of Existence, the IUCN Red List and the Reptile Database to investigate zoo turtle holdings on global and regional scales. Globally, zoo collections were representative of turtle diversity, regional species distributions and threat statuses, indicating no bias towards threatened species and no taxonomic or distribution blind spots. Species kept in zoos had significantly lower EDGE scores than those not represented, and threatened species were no more likely to have been bred in the year prior to data collection (before March 2022) or have non-viable populations, but were more likely to have a larger population size. Although Africa, Asia and South America have the smallest turtle holdings in terms of species, allowing for regional capacity, these regions hold more, while Europe holds fewer than expected turtle species – North American and Asian holdings do not differ from expected. African, Asian, North and South American regions significantly bias their collections towards native species. We found evidence for significant increases in turtle populations at the genus level following the EAZA Shellshock campaign in Europe. ZIMS data are limited by taxonomy, membership and accuracy of records but provide the best window into patterns of zoo turtle collections. While holding a species in a zoo does not equate to conservation value, based on these data, we recommend that conservation prioritisation exercises are developed for all turtle species, holding institutions or regional taxonomic advisory address population viability and support for institutions working with significant turtle populations in captivity to join ZIMS is provided. Keywords: chelonia, ex-situ, zoos, conservation, ZIMS

Genetic structure and diversity of green turtle (Chelonia mydas) in the Gulf of Thailand.

The International Union for the Conservation of Nature and Natural Resources lists the green turtle as endangered. Green turtle nesting behavior in the Gulf of Thailand has decreased to <50% of the 1995 level. The population structure of green turtles in the Gulf of Thailand has not yet been studied. This study aimed to characterize the genetic diversity of green turtles in the Gulf of Thailand based on comparisons of mitochondrial DNA (mtDNA) control region with sequences of Indo-Pacific management units (MUs) and rookeries, to investigate population structures, and to explore phylogeographic relationships. Blood samples (1 mL each) from 91 stranded green turtles were collected from four parts of the Gulf of Thailand (eastern, upper, central, and lower). The control mtDNA region was amplified by polymerase chain reaction using LCM15382 and H950 primer. The obtained 384-bp or 770-bp sequences were analyzed for haplotype, clade, and haplotype and nucleotide diversities and were used to construct a phylogenetic tree and haplotype network diagram, respectively. In addition, we analyzed genetic differentiation within and among populations of green turtles in the Gulf of Thailand and between green turtles in the Gulf of Thailand and other Indo-Pacific MUs and rookeries. In total, 12 (based on 384 bp) or 13 (based on 770 bp) haplotypes and two clades (clades VII and VIII) were identified, with nine or 10 haplotypes belonging to clade VIII and three haplotypes belonging to clade VII. Of the new haplotypes, four or five were identified and classified as clade VII (two haplotypes, for both fragment lengths) and clade VIII (two or three haplotypes, for 384 bp or 770 bp fragments, respectively). The overall haplotype and nucleotide diversity of green turtles in the Gulf of Thailand were high (0.755 ± 0.039 and 0.01146 ± 0.00248, respectively). Based on the analysis of molecular variance, green turtles in the Gulf of Thailand could be divided into two subpopulations (UC-Eastern Gulf of Thailand [UC-EGT] and lower Gulf of Thailand [LGT]). Comparisons with other MUs and rookeries in the Indo-Pacific showed that UC-EGT was not genetically different from the Peninsular Malaysia and Eastern Taiwan (Lanyu) MUs and the Terrangganu and Mersing rookeries, and LGT were not genetically different from Peninsular Malaysia, Sipadan, Brunei Bay, Eastern Taiwan (Lanyu), Scott Reef and Browse Island, and Gulf of Carpentaria MUs and the Perak, Perhentain Island, Redang, Pahang, and Vietnam rookeries. To the best of our knowledge, this is the first report to identify the haplotypes and clades of green turtles in the Gulf of Thailand and to show that the populations in the Gulf of Thailand not only present high genetic diversity but also have haplotypic endemism. Longer mtDNA fragments (770 bp) increased the resolution of the stock structure. Clade VII is a unique clade not only for Japan but also for Thailand and Malaysia, and CmP82 is a unique haplotype for both the Gulf of Thailand and Malaysia. Conservation and management of these populations are important to preserve the genetic diversity, biological diversity, and evolutionary potential of green turtles in the Gulf of Thailand.

The Ongoing Battle: Understanding the Population Trends of Green Turtles in Peninsular Malaysia

Sea turtles are crucial marine animals. They act as indicator to a healthy marine ecosystem. However, they are subjected to different challenges and threats which results of their declining population. This study looks at the population trends of sea turtles in Malaysia by examining the numbers of nests, eggs, and hatchlings in six states in Peninsular Malaysia which are Perak, Pahang, Melaka, Johor, Terengganu, and Negeri Sembilan. Statistical distribution, hatching success percentage, trend landing and hatching, and linear regression analysis are implemented. The results show that Terengganu, on the east coast, consistently has the highest numbers of nests, eggs, and hatchlings, highlighting its key role in sea turtle conservation. In contrast, Melaka has the lowest numbers, pointing where conservation efforts could be increased. This study provides valuable insights into the differences in green turtle populations across states and identifies critical areas for focused conservation strategies to better protect and help these endangered species recover in Malaysia.

Trophic history of Hawaiian green turtles as revealed by stable isotope ratios (δ13C, δ15N and δ34S) in the bones of museum specimens

Abstract Understanding consumer trophic status and long‐term dietary changes can yield information about impacts of altered habitats on their ecology. In Hawai'i, coastal ecosystems have been significantly modified by the introduction of invasive seaweeds and mangroves, high nutrient load and overfishing, but so far, much is still to be understood about how these changes have affected the green turtle (Chelonia mydas). This study analyzed stable carbon, nitrogen, and sulfur isotope ratios in the bone tissue of modern and museum specimens of green turtles collected from 1901 to 2020 in Oahu and the North‐western Hawaiian Islands to understand how their isotopic niche has changed through time, a crucial step towards restoring the ecological role of a formerly decimated species. The standard ellipse size and the total area of the convex hull of the isotopic niche of green turtles in three periods (1901–1951, 1992–2008, and 2018–2020) were calculated. The stable isotope values of ancient green turtles (1901–1951) suggest that they relied heavily on macroalgae even before the introduction of exotic species and eutrophication promoted the development of algal pastures. However, a few ancient green turtles relied heavily on seagrasses, and others complemented their macroalgae‐based diets with significant amounts of animal matter. Such diet specialists were missing from the sample of current green sea turtles, suggesting that these foraging strategies are less common or perhaps even absent in the current population. The results suggest that green turtles have converged on the use of the most abundant resource, red macroalgae, likely because of the homogenization and simplification of coastal habitats and food webs due to anthropogenic influences. Restoring the population size of herbivorous fishes and a more diverse ecosystem structure may be necessary to recover the array of trophic strategies formerly present in the Hawaiian green turtle population.

Uso de los Sistemas de Vídeo Estereoscópico Submarino Remoto pelágicos (stereo-BRUV) para el estudio de las tortugas marinas en aguas atlánticas

The pelagic oceanic zone is one of the largest ecosystems on the planet, which is exposed to different anthropogenic pressures. In order to study and promote biodiversity conservation measures on these ecosystems, it is necessary to know the distribution of the species, the use of the habitat, the degree of connectivity and the status of populations. Carrying out such monitoring for pelagic and migratory species is complicated due to the fact that their distribution is not homogeneous and they can be widely distributed in different habitats, as is the case of sea turtles. In recent years, Baited Remote Underwater Stereo-Video (BRUVS) have become a popular tool to assess in a non-intrusive way. This innovative technique can provide us with important new information, in particular for the conservation of sea turtle populations by providing strategic knowledge about areas that have not been thoroughly studied, such as feeding areas and migration corridors in pelagic-coastal zones.

Design Build an Off Grid Based Solar Power Plant System Using The Bidirectional Buck And Boost Topology In The Conservation Of Sea Pearl Turtles

Turtles are one of the fauna that is threatened with extinction. The cause of its extinction is inadequate management of conservation techniques. The Lantera Trenggalek Community sees the problem of the high operational costs of turtle conservation faced by the people of Masaran Village, Trenggalek, East Java. The operational costs of turtle conservation are high, including the costs of turtle feed, turtle maintenance and the electricity costs for turtle egg incubators reaching 1800 watts, so they require high PLN electricity. Therefore, this research aims to innovate to overcome partner problems by utilizing off grid PLTS using Bidirectional Buck and Boost Converter. The aim of using PLTS in Masaran village is to increase the availability of electricity sources at relatively low prices. However, in the PLTS implementation system, the electrical energy produced is unstable. So the PLTS system is equipped with batteries to store energy. The energy storage process requires a converter which functions to stabilize the output voltage of the PLTS. This research used Bidirectional Buck and Boost Converters because these converters are able to work in two directions so they can optimize the output voltage from PLTS. The results of testing the PLTS system with Bidirectional Buck and Boost Converter show that when in buck mode, the converter output voltage can reach 14.4V which is used for battery charging. The output of this research is that the Off Grid PLTS system can produce maximum electrical energy so that it can overcome partner problems in increasing the turtle population.

Comparative plasma biochemistry analyte data in nesting leatherback (Dermochelys coriacea), foraging green (Chelonia mydas) and foraging and nesting hawksbill (Eretmochelys imbricata) sea turtles in Grenada, West Indies.

Blood biochemistry represents a minimally invasive tool for monitoring sea turtle health, assessing injured sea turtles and supporting conservation strategies. In Grenada, West Indies, plasma biochemical variables were examined in 33 nesting leatherback (Dermochelys coriacea), 49 foraging green (Chelonia mydas), 49 foraging hawksbill (Eretmochelys imbricata) and 12 nesting hawksbill sea turtles sampled between 2017 and 2022. Plasma biochemistry reference intervals are described herein except for nesting hawksbills, which are represented by descriptive statistics due to the low sample size. Select analyte concentrations were positively correlated with curved carapace length in leatherbacks (chloride), green turtles (total protein, albumin and globulin) and foraging hawksbills (total protein, albumin and phosphorus). Cholesterol (7.8 mmol/l ± 1.6 SD) and triglyceride (6.9 mmol/l ± 1.9 SD) concentrations were significantly higher in leatherbacks compared to foraging green turtles, foraging hawksbills and nesting hawksbills (P < 0.001 for all). Cholesterol was significantly higher in nesting hawksbills compared to foraging green turtles (P = 0.050) and foraging hawksbills (P = 0.050). Foraging hawksbills demonstrated significantly higher aspartate transaminase activities than leatherbacks (P = 0.002), green turtles (P = 0.009) and nesting hawksbills (P < 0.001). Biochemical results provide baseline population health data and support guidance for treatments during clinical sea turtle rehabilitation efforts. They also provide insight into species-specific physiologic differences and preludes further studies to better characterize the impacts of life-stage class on biochemistry reference intervals to better support wild sea turtle populations in Grenada.

New nesting site for the expanding green, olive ridley and hawksbill turtle populations in Cabo Verde

Currently, some sea turtle populations are expanding their home range distribution toward higher latitudes at an unprecedented rate. These expansions are associated to factors such as climate change or and increased conservation efforts. Already home to one of the largest loggerhead turtle (Caretta caretta) rookeries in the world, the islands of Cabo Verde Archipelago have recorded sporadic nesting of green (Chelonia mydas), olive ridley (Lepidochelys olivacea) and hawksbill (Eretmochelys imbricata) turtles in recent years. Here, we present the compiled information on these sporadic nesting events that occurred between 2013 and 2022 and discuss possible causes for their occurrence. Throughout the study period, the green turtle was documented on 20 occasions, the olive ridley on 25 occasions and the hawksbill on three occasions. All nesting females were found untagged and were subsequently tagged. Nesting activities occurred on the islands of Santo Antão, Sal, Boa Vista and Maio, most of them within the Sea Turtle Natural Reserve in Boa Vista Island. We suggest introducing new conservation strategies targeting the green, olive ridley, and hawksbill turtles nesting in Cabo Verde. We further suggest the use of genetic studies to determine the population origins of these three species.

Nesting Ecology of Lepidochelys olivacea in Lobito, Angola.

The scarcity on the Atlantic coast of the African sea turtle population and its dynamics data is well known. This article discusses the nesting ecology methods and analysis of a nascent Angolan project aimed at preserving the nesting female population of the Olive Ridley turtle (Lepidochelys olivacea) on the coast of Lobito. This study examines the nesting ecology of this species from 2020 to 2023. Females had an average CCL of 70.2 cm and CCW of 68.5 cm. These females laid 127 eggs in nests that averaged 47.0 cm deep. The ex situ nest incubation period averaged 60 days, and the hatchling success was 82.1%. Some techniques used in this project require modifications and enhancements. The utilization of photo identification did not yield the anticipated outcomes, prompting the adoption of passive integrated transponders (PITs) in the last season. However, due to limited funding, the success of this method is contingent upon an augmented field effort, allowing for the recapture of a larger number of females. The continuity of this project hinges upon collaboration between higher authorities and the local community. Together, it is possible to deepen the understanding of the nesting ecology of this species and address pivotal issues for its conservation, thereby implementing the most effective preservation measures.

Special Interest Tourism Development at Tongaci Beach Tourism, Sungailiat, Bangka Belitung

The tourism sector is one of the largest and strongest sectors in the world economy and is one of the main drivers of the world economy which is able to provide quite a large amount of foreign exchange for the country. One of the fastest growing tourism sectors in the tourism industry is special interest tourism which shows that tourists are starting to demand more varied and stimulating holiday experiences. The aim of this research is to develop special interest tourism in the form of Hatchlings Babel Sea Turtle Conservation in Bangka Belitung which is a conservation site to maintain and minimize the decline in turtle populations, especially in Bangka Belitung waters. The method used in this research is a qualitative method where the data obtained is by conducting direct observations and interviews at the Babel Tukik Conservation. Hatchlings Babel Sea Turtle Conservation is also used as a special interest tourism facility as well as an educational place so that local people and foreign tourists can get to know more about sea turtles and it is hoped that awareness will arise to preserve sea turtles from the threat of extinction and damage to the marine ecosystem due to sea tin mining and illegal hunting

A Test of Intersexual Trophic Niche Partitioning within a Population of Wood Turtles (Glyptemys insculpta)

A Test of Intersexual Trophic Niche Partitioning within a Population of Wood Turtles (Glyptemys insculpta)

Regional differences in Hg contents in the liver and muscle of the green turtle (Chelonia mydas) from three foraging grounds in Northeast Brazil.

Mercury (Hg) is a highly toxic pollutant that endangers several marine animals, including green sea turtles (Chelonia mydas), particularly in their foraging grounds along Brazilian coastal waters. Environmental Hg levels differ along this extensive littoral, rendering mandatory Hg long-term assessments of the different Hg fate in different sectors of the Brazilian coast. This study quantifies total Hg concentrations in the liver and muscle of green sea turtle populations from three foraging coastal regions in northeastern Brazil and analyzes Hg concentration differences given the locality and size of 61 juvenile individuals sampled. The results showed wide variations in Hg concentrations in the liver (81-3135 ng g-1) and muscle (10.1-8569 ng g-1). There was no significant correlation between animal size and Hg concentrations. Also, no difference was found among areas, reflecting the opportunistic feeding habit of juveniles of this species. This suggests that, in the case of green turtles, the ontogenetic change of diet plays an important role in influencing Hg concentrations found in this species.

Sustainable mindsets: Combining traditional indigenous knowledge with non-aboriginal understanding to address environmental risks

Aboriginal and Torres Strait Islander peoples are the traditional owners of Australia. It has been predicted that they have been the custodians of these lands for at least 60,000 years. Their traditional lands are inextricably linked to their languages, cultural practices and spiritual being. As the custodians they have used their traditional Indigenous knowledge to care for the land – its plants, animals and waterways, protecting unique ecosystems and maintaining sustainability. In fact, their traditional understanding reflects what has been described in the literature as a sustainable mindset. We come together as non-Aboriginal and Aboriginal educators to explore how environmental threats within the epoc of Anthropocene may be addressed using such a sustainable mindset – one reflecting both indigeneity and posthumanism perspectives. We describe three case studies showing how the use of traditional knowledge held by local Indigenous communities (IPLCs) can be used with non-Indigenous knowledge to address human induced planetary changes to protect important animal species and the land on which they live. We draw on written and oral reports from our Indigenous co-authors and data obtained informally from them by way of ‘yarning’. We describe how in the north-west of Western Australia areas of significant ecological and cultural value are being negatively affected by human-induced change threatening different animal species and ecosystems. We outline the effects of light pollution in Port Hedland and how this is disrupting the life cycle of the flatback sea turtle - culturally significant sea animals. As a point of comparison, we next describe how green back turtle and Dugong populations are being protected and sustained on the Dampier Peninsula using traditional knowledge more recently supplemented through the work of the Bardi Jawi Rangers. Finally, we examine how the Fitzroy River catchment area is increasingly under threat from water extraction and mining, but how a sustainable mindset can be used to obviate these environmental risks.

Marine turtles, umbrella species undergoing recovery

Marine turtles inhabit various coastal and marine ecosystems and play significant ecological roles throughout their life cycles. Because of the significant overlap with other species at risk in their geographic ranges, the successful conservation of marine turtles also protects numerous co-occurring species, a phenomenon known as the “umbrella species effect.” Since several marine turtle populations have shown positive trends, suggesting incipient recovery, it is expected that their umbrella characteristics will coevolve as their populations grow and expand. Recognizing the considerable potential of marine turtles as umbrella species, we advocate for promoting this concept and explicitly integrating it into management and recovery programs. This approach would facilitate concurrent benefits not only for marine turtles but also for other species and their associated habitats. To achieve this goal, we analyzed the conservation status of marine turtles in the Gulf of Mexico and Western Caribbean within the framework of the legal regulations. Additionally, we reviewed the current challenges in marine turtle recovery in the framework of ecological restoration, while also aiming to target and encourage their utilization as umbrella species.

Successful reproduction of female loggerhead sea turtles with severe limb amputations

AbstractWe evaluate the frequency of flipper amputation and its impact on reproduction in the threatened loggerhead turtle (Caretta caretta) population of the Eastern Atlantic, through a long‐term study on several high‐density nesting beaches of Cabo Verde. 5982 adult females were individually identified, tagged and measured, and the presence of limb amputations was recorded. 918 of them had one or multiple amputations of the rear or front flippers. Most of these turtles (n = 778) had partial rather than complete flipper amputations. However, we found no difference in body condition indices (1.2 vs. 1.1), clutch size (82 vs. 83 eggs), or hatching success (79 vs. 80%) between amputated and non‐amputated females. While amputations may cause individual mortality or reduced fitness, our results indicate that some amputated turtles successfully nest and survive across multiple nesting seasons. Moreover, the amputations do not appear to be impacting the strong recovery of this population. This study provides evidence of the successful reproductive capacity of amputated loggerhead sea turtles and, by extension, the potential reproductive success of amputees released from recovery centers.

Effects of wetland connectivity on overwintering and movement behaviours of Australian freshwater turtles

AbstractFreshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety‐Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re‐entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter.

Health status and genetic compositions of green turtles (Chelonia mydas) foraging in Brunei Bay.

Long-term monitoring of sea turtle aggregations is critical for understanding the impacts of environmental changes on their population health and habitat suitability. Brunei Bay is a significant foraging ground for green turtles in the South China Sea. We analyzed the body size, hematology and body condition of green turtles for their health status in their foraging ground in Brunei Bay over a period of nine years (2011-2019). Additionally, we used mitochondrial DNA (mtDNA) to evaluate changes in the size and genetic composition of green turtle aggregations. Our findings revealed that the size composition of the green turtle population varied seasonally, but there were no significant temporal changes in genetic and size compositions. Hematology parameters and Fulton's body condition index were consistent with those reported for apparently healthy green turtles. Furthermore, we found that blood reference intervals indicated the turtles were healthy. These results provide valuable baseline data for future comparisons with other foraging aggregations and for long-term monitoring of green turtles in Brunei Bay.

Interacciones potenciales entre embarcaciones menores y zonas de agregación de tortugas marinas en Isla Arena, Campeche

Within the Gulf of Mexico, five of the seven species of sea turtles are distributed and carry out essential stages of their life cycle. The marine habitats of sea turtles are subject to various threats, including bycatch and boat traffic. The aim of this study was to identify, in the marine portion of Isla Arena, Campeche, sites of use of space for its feeding, internesting, and migration stages, as well as potential zones of interaction with small vessels distributed in the study area. For this, satellite tracking of three species of post-nesting female sea turtles: 1 hawksbill turtle (Eretmochelys imbricata), 4 Kemp´s ridley turtle (Lepidochelys kempii), and 7 green turtle (Chelonia mydas), with which the home range was estimated, and through a grid of the study area made up of 170 hexagons of 21 km2 area, the sites of the intensity of space use were estimated for each life stage. With this information and the quantification of vessels identified in the marine area of Isla Arena from January 2017 to December 2019 through Sentinel-2 satellite images, the areas of greatest interaction in three different seasons were identified. As a result, the sites with the highest use of space in the feeding stage are the south and north of Isla Arena, while for internesting the line parallel to the coast is where the highest use occurred; for migration, most of the study area has a use that goes from high to regular. Regarding the potential interaction with boats, feeding season one (January to April) was the one that presented the greatest interaction in the north and south of Isla Arena, while the west and north represent the areas of highest interaction for migration during season three (September to December), and season two (May to August) for internesting. The results of this research highlight that number of small boats activity represents another important stressor for important aggregation zones for sea turtle populations. Keywords: Turtles, interaction, vessels, track, marine.

Mexican legal and administrative framework for the evaluation of sea turtle restoration programs

This document provides a historical overview of the National Sea Turtle Conservation Program (pnctm) from the perspective of public policies on environmental matters. Initially, a timeline is presented, highlighting some of the most significant events since the beginning of the pnctm, considered one of the oldest conservation programs in Mexico. In the second part, the conceptual framework that underlies the Conservation of Species at Risk Program (pace) is analyzed as the tool for managing public policy and that, as such, must be subject to processes essential for project management, such as evaluation. In this context, the importance of the evaluation processes of public policies (their programs and projects) is highlighted as a means for insight that led to improvements in their contents and in the processes of program implementation, orienting them towards adaptive management to improve results. In this case, this entails the recovery of sea turtle populations. An overview of some exercises for the evaluation of species recovery plans at the international level and in Mexico is presented. From this we conclude that there is a critical urgency to evaluate the results of the recovery plans, such as pace. Keywords: Environmental public policy, public policy evaluation, sea turtles, PACE

Overwintering site fidelity and communal hibernation predispose Northern Map Turtles to mass mortality events

Mass mortality events appear to be increasing in intensity and frequency, so understanding their causes and consequences is imperative for wildlife conservation. We report on a mass mortality event in a population of Northern Map Turtles ( Graptemys geographica (LeSueur, 1817)). At a communal overwintering site, 142 carcasses (ca. 10% of population) were recovered, seemingly depredated by river otters ( Lontra canadensis (Schreber, 1777)). We compared the size and sex of the carcasses to those of turtles that survived. Smaller turtles and males were more likely to be depredated than larger turtles and females. Using captures made at the same overwintering site between 2003 and 2022, we assessed the vulnerability of this population to mass mortality events during winter. Nearly 60% of the 1875 turtles marked between 2003 and 2022 used the overwintering site where the mass mortality event occurred at least once. On average, turtles overwintered at the site at least 38% of the winters between their first and last capture. Our study shows how behaviour and physiology interact to predispose a species to mass mortality events and ecological traps. Protecting overwintering sites and minimizing human pressures affecting winter depredation may be essential for the preservation of certain turtle populations.