. - The Mississippi Alluvial Plain (MAP) of Arkansas is a landscape where many wetlands have been altered for use as aquaculture ponds or agricultural ditches. Commercial harvest of freshwater turtles within the MAP is not restricted or limited, with reported harvest numbers for 2019 alone exceeding 4000 for spiny softshell turtles (Apalone spinifera) and 39,000 for red-eared sliders (Trachemys scripta elegans). Herein, we attempt to provide baseline estimates of freshwater turtle densities and community composition in aquaculture ponds and agricultural ditches of eastern Arkansas, the habitat types most frequently trapped by commercial harvesters. We used a capture-mark-recapture approach over 3 summers (2019-2021) to evaluate population densities and community composition of freshwater turtles in these anthropogenic aquatic habitats. We captured > 4000 individuals of 9 species of turtle. One species, the redeared slider, dominated the turtle community in both anthropogenic aquatic habitats, comprising 66% (+/- 22% SD) of all captures in agricultural ditches and 63% (+/- 32% SD) in aquaculture ponds. Diversity and richness did not differ between aquaculture ponds and agricultural ditches. We estimated densities of the 2 most commonly captured species, the red-eared slider and spiny softshell turtle. Density of red-eared sliders ranged from 0 turtles/unit area (linear kilometers in ditches or hectares in ponds) to 500 turtles/unit area, with a median of 37 turtles/unit area. The spiny softshell turtle was more frequently captured in ponds than ditches and attained average densities of 25 (+/- 19) turtles/ha and 7 (+/- 4) turtles/linear km, respectively. Our mean density estimates were lower than those in reported literature, including estimates from similar habitats, such as urban ditches and farm ponds, which resemble our study sites in structure, use, and geographical placement. We estimate the region contains 22,317 ha of aquaculture ponds and 18,350 linear km of agricultural ditches. By extrapolating our density estimates to each anthropogenic aquatic habitat type, we estimated 2 million red-eared sliders and 427,000 spiny softshell turtles occurred in aquaculture ponds and agricultural ditches across eastern Arkansas. Our results suggest that these altered wetlands provide abundant habitat for only a few generalist turtle species.
We present a long-term time series of annual nesting data (1987-2024) to update the population status of the hawksbill sea turtle (Eretmochelys imbricata) rookery at Jumby Bay (Long Island), Antigua, an index site in the eastern Caribbean. The 38-yr saturation tagging nesting dataset reflects an initial period of population stability followed by increasing abundance, as disseminated in previous population updates; however, we report on a contemporary pattern that has emerged over the past decade whereby the population has exhibited increased interannual volatility (i.e., year-to-year fluctuations), with an underlying trend reflecting steep decline. We discuss potential drivers of this change- including changing conditions in foraging areas and the proliferation of Sargassum macroalgae-but causation remains unclear, and we are eager to ascertain more context to determine whether the Jumby Bay pattern is isolated or could reflect broader regional trends.
The Rio Grande cooter (Pseudemys gorzugi) is a conservation-reliant riverine turtle native to the lower Rio Grande basin and its tributaries. Although research on this species is expanding, significant gaps remain in our understanding of its nesting ecology. To fill in some of these gaps, we conducted surveys from 2020 to 2022 of the Rio Grande cooter on the Black River in New Mexico, aiming to document the habitat, incubation period, predation, and seasonality of nests. We used satellite telemetry and visual encounter surveys to locate nests and characterize the habitat along with deploying protective nest cages and game cameras to identify predators and determine incubation periods. We found nests at a mean distance of 5 m (6 4.2 SD) from the water's edge. Locations tended to be clustered, with 95% of nests being within 0.5- 75 m of at least 1 other nest. Out of 5 intact nests, 2 nests successfully hatched in September after incubation periods of 78 and 91 d. Raccoons (Procyon lotor) were the only predators observed at nests monitored with game cameras. All 5 direct observations of nesting occurred in mid-June, whereas additional ultrasound images of 155 P. gorzugi, collected May-July, revealed a peak in the proportion of gravid females from late May to June. Overall, our findings provide baseline data on nesting events and nest locations of P. gorzugi along the Black River. This knowledge will aid in the planning of future nesting ecology studies on the Black River and provide a framework for conservation measures, including identifying possible locations for protective buffer zones where human and predator disturbances are reduced during peak nesting and hatchling emergence periods.
- Nest-site choice is important for species with temperature-dependent sex determination (TSD) because nest attributes determine not only incubation temperatures and therefore hatchling sex, but also performance, survivorship, and phenotype. However, suitable nesting habitat can be limited for aquatic species that nest in areas impacted by anthropogenic activities. The purpose of this study was to examine nest-site choice and nesting ecology of painted turtles (Chrysemys picta picta 3 C. p. marginata) inhabiting an anthropogenic wetland in south-central Pennsylvania. Visual surveys were conducted for nesting females along a perimeter dirt path and along an adjacent railway access road next to inactive fish hatchery ponds. From 2010 to 2013, we documented nest location, depth, width, temperature, canopy coverage, clutch size, and hatching success for a total of 33 nests. To address the influence of soil characteristics on nest selection, in 2016 we collected and analyzed 60 soil samples from 1) nests (with oviposition, n = 20), 2) test nests (nests aborted prior to oviposition, n = 20), and 3) randomized locations within the nesting area (n = 20). Nests were shallower than historically observed for this species and linearly aggregated north of the pond. Nests were made in soils with more coarse grains and fewer fine grains relative to test nests and random locations. Additionally, nests along the railway access road had markedly higher total carbon compared with nests on the dirt path. Although the railway may have increased solar exposure by reducing canopy coverage, this structure may also limit turtles' access to suitable nesting habitat that could negatively impact future nest success.
- The Northern Map Turtle (Graptemys geographica LeSueur 1817) occupies large lakes and river systems in southern Ontario and southern Quebec, Canada, and the northeastern United States. The species is highly aquatic and basks conspicuously, which allows for reliable sighting and mapping of the species' distribution. We document a long-distance movement approximating 60 km by watercourse of an adult female Northern Map Turtle and extralimital observation at the species' northern climatic range limit and provide growth data from captures over a decade apart. These opportunistic resightings suggest that Northern Map Turtles are more mobile than generally recognized and highlights the importance of habitat connectivity to facilitate long-distance movements.
Kyphosis is a spinal column defect that produces a hunched-back phenotype and is 1 of the most distinctive and often reported shell anomalies in turtles. I compiled records of the occurrence of kyphosis in turtles from the literature, from personal communications with colleagues, and my own unpublished data. This effort resulted in 568 records from 188 studies representing 10 of 14 families, 37 of 97 recognized genera (38%), and 71 of 357 species (20%). For reports that provided population sample sizes, 501 of 280,382 individual turtles (0.18%) were kyphotic. Kyphosis has been reported in only 6 of 96 (6%) recognized pleurodiran species compared to 64 of 261 (24%) recognized cryptodiran species, but this difference may reflect failure to record data rather than a difference associated with phylogenetic divergence. Reports of kyphosis are most frequent among trionychids and podocnemids, more common among females than males, and more common in species with genetic sex determination versus temperature-dependent sex determination; correlation with latitude may exist in some species. This deformity is well documented in embryos, hatchlings, and juveniles, indicating a typical embryonic origin; however, posthatching development of kyphosis following traumatic boat strike injury has also been reported. Surprisingly, the impacts of kyphosis on individual fitness seem to be minimal. Of the many potential factors proposed to explain the etiology of kyphosis in turtles, the most probable appear to be extreme environmental conditions (especially incubation temperature and pollutants) during midincubation, when they might interfere with normal developmental rates.
To monitor the impact of climate change on sea turtle nesting beaches, we measured the sand temperature at 3 specific nesting locations for loggerhead turtles (Caretta caretta), green turtles (Chelonia mydas), and hawksbill turtles (Eretmochelys imbricata) at Nishinohama Beach on Kuroshima Island, Ryukyu Archipelago, Japan. During the major incubation periods (peak of nesting season) from 2009 to 2023, sand temperature surrounding nests ranged from 28.72 degrees C to 30.45 degrees C for loggerheads, 28.46 degrees C to 30.04 degrees C for green turtles, and 28.60 degrees C to 29.36 degrees C for hawksbills. Estimated historical (since 1897) sand temperatures based on recorded climatology data indicate that sand temperatures at nesting microsite locations increased by 1.29 degrees C, 1.12 degrees C, and 1.18 degrees C per 100 yrs for loggerheads, green turtles, and hawksbills, respectively.
The Asian narrow-headed softshell turtle, Chitra chitra Nutphand, 1986, one of the world's largest freshwater turtles, inhabits Thailand, peninsular Malaysia, and Indonesia and faced severe population declines in the recent decades, now listed as Critically Endangered by the IUCN. In Thailand, while C. chitra is known to inhabit the Mae Klong River and Mae Ping River, its ecology and population status are poorly understood. Our field surveys and informal discussions with local people along the Mae Klong River in Kanchanaburi and Ratchaburi provinces confirmed the species' continued presence in its historical range after a 20-yr gap in published records, also documenting its habitat and threats at the local scale.
Over a 15-yr period (2008-2022), 7802 cold-stunned sea turtles were found stranded in Massachusetts, of which 5028 (64%) were found alive. Annual stranding numbers increased over time. Species composition included 87% Kemp's ridley turtles (Lepidochelys kempii, of which 64% were alive), 8.2% loggerhead turtles (Caretta caretta, of which 68% were alive), 4.5% green turtles (Chelonia mydas, of which 67% were alive), 0.3% undetermined species (of which 46% were alive), and 1 deceased hawksbill turtle (Eretmochelys imbricata). Live turtles were medically stabilized at a primary care facility, after which most turtles (70%) were transferred to secondary care facilities for further care, while others remained at the primary care facility to complete rehabilitation. Overall, 76% of turtles admitted alive were released to the wild after rehabilitation, generally within 3 to 8 mo of stranding, including 75% of Kemp's ridley turtles, 86% of loggerhead turtles, and 78% of green turtles. Most deaths for all species occurred at the primary care facility within the first 4 days of hospitalization. After stabilization and transfer to secondary facilities, 91% of Kemp's ridleys, 97% of loggerheads, and 96% of green turtles were later released. Medical management protocols were adjusted over time because of the increasing caseload and the COVID-19 pandemic, yet success rates remained high. This study indicates that rescue and rehabilitation of cold-stunned turtles in Massachusetts results in a high rate of release to the wild, and that management protocols can be thoughtfully refined to retain high success rates despite increasing caseload and operational restrictions.
Citizen science has enormous potential to gather important information on endangered marine wildlife in largely understudied areas, especially in locations with fast-growing tourism industries. Our study focuses on data collected through TurtleWatch Egypt (TWE), a citizen science initiative implemented to better understand marine turtles in the Egyptian Red Sea. The photos and videos that were provided by data collectors over 13 yr (2011-2023) enabled individual identification and long-term monitoring of green (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata), enhancing knowledge of their distribution, injury patterns, and recovery rates. Over the study period, 8769 turtle sightings were reported, identifying 778 unique individuals across 225 locations. Notably, 5% of these turtles were recorded with injuries, with vessel strikes accounting for 35% of injuries, particularly in high-traffic tourist areas such as Marsa Abu Dabbab, Hermes Bay, Makadi Bay, and Naama Bay. Although 31% of injuries were classified as severe, 53% of these showed signs of natural recovery over time, suggesting resilience among the turtles. This study's findings were consistent with global research on high vessel-strike rates in areas with heavy boat traffic and indicate that green turtles in particular face significant risks in shallow coastal regions frequented by motorized boats. Although citizen science data had some limitations, such as the inability to determine injury causes for 46% of cases, the long-term data gathered through TWE provided critical insights into the self-healing abilities of turtles in the wild. This is particularly significant as no rehabilitation center operates in the Red Sea, making natural recovery crucial for injured turtles. Our findings also underscored the potential for citizen science in raising awareness and promoting safe, hands-off monitoring practices among local dive communities.
. - Hematological and biochemical analyses are widely employed to investigate health conditions and physiology of wild and captive animals. This study provides the first reference (Mesoclemmys vanderhaegei). It was determined the hematological and plasma biochemistry values of free-living M. vanderhaegei in an anthropic habitat in southeastern Brazil, considering individuals' sex and body size. Males presented higher values of red blood cells and creatinine, whereas females showed higher values of mean corpuscular hemoglobin concentration. However, no effect of body size at the sampled range has been found. Our study fills a critical knowledge gap by establishing comprehensive reference values for hematological and biochemical parameters in M. vanderhaegei, shedding light on the health and physiological variations within this species in an anthropic habitat in southeastern Brazil.
The Sonoyta mud turtle (Kinosternon sonoriense longifemorale) is an endangered subspecies that inhabits a small section of the Sonoyta River in Sonora, Mexico, and Quitobaquito Springs in Arizona, USA. To assess the status of this subspecies in the Sonoyta River basin, we surveyed all historical localities for extant populations of turtles. At sites where turtles were detected, we conducted quantitative trapping and visual encounter surveys to facilitate capture-mark-recapture techniques and population size estimation. Sonoyta mud turtles were absent from 2 historical sites, but we report 1 previously undocumented locality. Demographic analyses revealed sex-based differences in survival probability, with males exhibiting a lower survival rate than females, contributing to the consistent female-biased sex ratios and reduced male abundance. Abundance estimates for the Papalote reach were comparable to or exceeded historical values, while populations at most other localities appeared to be in decline. Entry probabilities were low, suggesting limited recruitment or immigration into the active population, consistent with the hydrological isolation of the Papalote reach. We documented sexual size dimorphism, with adult females exhibiting significantly larger body mass and straight carapace length than males. Although Sonoyta mud turtles persist in the Sonoyta River, their long-term viability is uncertain because of projected declines in surface water, and their survival appears dependent on continued human management.
Widespread sound production across turtle taxa raises questions about its possible function. Although most acoustic communication has been observed in adults, acoustic behavior may play different roles across ontogeny, developing over the protracted lifespan of chelonians. Little is known about the changes in the acoustic repertoires across ontogeny or whether the extent of change varies among lineages. Such knowledge would provide the fundamental natural history information needed to better understand the behavioral evolution of this group of reptiles. Here we investigate if turtles' acoustic repertoires undergo ontogenetic changes, and if such changes are similar throughout the turtle phylogeny. If ontogenetic changes in vocalizations simply reflect predictable, morphological changes that occur with growth, then we predict dominant frequency will decrease across ontogeny in all chelonian species, and vocal complexity will remain constant. If, however, ontogenetic changes represent functional changes in acoustic communication, then both dominant frequency and vocal complexity will vary across ontogeny in a species-specific manner. Here we collected and compared sound recordings from 6 species in different life stages and found that the acoustic repertoire of some species does not grow in a simple manner across ontogeny, challenging the hypothesis that mean peak frequency decreases with body size. We discuss the possibility that changes in habitat use during ontogeny has driven concomitant changes in vocal repertoire, whereas continuity in habitat leads to a relatively stable repertoire across life, especially in species that socialize among individuals of all ages.
- The Painted Wood Turtle (Rhinoclemmys pulcherrima) is a medium-sized turtle comprised of four subspecies that are distributed from northern Mexico to Costa Rica along the Pacific coast. Along this distribution, R. pulcherrima occurs in a variety of habitats, with many other turtle species, yet the ecology of R. pulcherrima remains poorly studied. Rhinoclemmys pulcherrima is popular in the international pet trade for its stunning red coloration, and in captive populations it is known as a semiterrestrial and omnivorous turtle. In this study, we conduct field work in 3 states in Mexico, and we use measurements on museum specimens to document ecology of R. pulcherrima. Field techniques utilized include visual encounter surveys, mark-recapture, radiotelemetry, and morphological measurements. This field work was complimented with limb, shell, and head measurements off all R. pulcherrima subspecies to explore potential ecological differences. Results from the field on the 3 subpopulations in Mexico demonstrated that R. p. pulcherrima and R. p. rogerbarbouri 1) exist in low densities and 2) occur near or in rocky-forest streams, and 3) adult size and sexual size dimorphisms can vary substantially among sites. Data on museum specimens suggest that southern subspecies (R. p. incisa and R. p. manni) could be more terrestrial, characterized by less interdigital webbing, taller shells, and larger heads than their northern counterparts R. p. pulcherrima and R. p. rogerbarbouri. This study provides the first ecological insight into the charismatic R. pulcherrima in the field and highlights important sources of variation among subpopulations and subspecies that merit future investigation. Last, our findings that R. pulcherrima exist in low densities is worrisome given that there is a high demand for all 4 species in the illegal pet trade.
. - A full understanding of life-history patterns and their evolution in turtles has been impeded by data gaps, particularly for reproductive data, for most species. With the goal of enabling a better understanding of turtle life-history variation and its correlates, we amassed a data set of traits for 2466 populations (captive and wild) of 323 species of turtles, including members of all 14 turtle families and 90% of the 357 extant, currently recognized species. For each turtle population, the data set includes general locality and latitude, habitat, diet, female carapace length and body mass, age at maturity, mean clutch size, egg shell type, mean egg length, width and mass, clutch mass, relative clutch mass (clutch mass/gravid body mass), clutch frequency, longevity, and data sources. The data set still lacks reproductive data of any kind for 34 species but represents the most complete assemblage of turtle life-history information to date.
- The Sultanate of Oman has 26 officially declared protected areas, 3 of which encompass critical nesting and foraging grounds for multiple sea turtle species. Traditional research and monitoring in Oman started in the 1970s with a range of activities focusing on flipper tagging and satellite tagging nesting females and nesting success surveys, but this method has limitations, due to potential tag loss and erosion of tag information. To date, most efforts have been concentrated on Masirah Island, with limited and sporadic initiatives in Ras al Hadd Turtles Reserve and the Dimaniyyat Island Nature Reserve (DINR). Little historical information has been collected on turtles in the Musandam Nature Reserve. This study utilizes Photo-ID as a population-monitoring technique, which offers a noninvasive method for identifying and monitoring sea turtles based on unique facial scale patterns, targeting sea turtle populations around the primarily Musandam Peninsula from 2019 to 2023. This technique has the advantage of including male and juvenile individuals of the population that are excluded from nesting sea turtle research, which is female focused. Over the monitoring period 828 sea turtle encounters were recorded, leading to the identification of 147 individual green turtles (Chelonia mydas) and 9 hawksbill turtles (Eretmochelys imbricata). The data highlight a significant juvenile sea turtle population with sporadic adult sightings, suggesting a use of the region's habitats for foraging and resting. Here we underscore the importance of Photo-ID in filling knowledge gaps concerning in-water sea turtle activity and spatial distribution, particularly for the identified juvenile population. This study provides baseline data on the in-water sea turtle population of Musandam. We demonstrate how Photo-ID contributes to long-term conservation efforts by improving population monitoring and population dynamics analysis, contributing to conservation efforts in Oman and in the northwest Indian Ocean.
. - Four loggerhead turtles (Caretta caretta) with 81.0-85.3 cm curved carapace length were satellite tracked off Fujian and Guangdong provinces, southern China, in 2017 and 2022, and 2 movement patterns were revealed: resident and long-distanced seasonal migration. Identified hotspots include the eastern waters of Leizhou Peninsula, southern Taiwan Strait, central East China Sea, and the area between the southern Yellow Sea and the northern East China Sea. This study contributes foundational data for the North Pacific Regional Management Unit and highlights the need for cooperation among countries in East Asia.
. - Chronic threats and mass-mortality events in urban areas impact wildlife and can disproportionately affect turtle populations because their slow life history limits population recovery. Demographic studies of urban turtles are important, especially where ongoing conservation efforts (e.g., headstarting) occur and historical data on species status are absent. Our study focused on a community of headstarted Blanding's (Emydoidea blandingii) and naturally occurring painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles that inhabit a wetland complex in an urban area of Toronto, Ontario, Canada. We assessed demography and biomass at 3 sites using mark-recapture data collected from 2018 to 2021. Abundance estimates were highest for painted turtles, followed by Blanding's and snapping turtles, while survival estimates varied depending on the species. Sex ratios of Blanding's turtles in human care and postrelease were similar. Both painted and snapping turtles displayed unbiased sex ratios, except at 1 site, where painted turtles displayed a female-biased sex ratio. The Blanding's turtle population was juvenile-biased because they are part of an ongoing headstarting program, whereas the painted and snapping turtle populations were adult-biased. Biomass of snapping turtles was the highest despite low abundance, highlighting their functional role in the ecosystem. Our findings indicate that turtle communities can persist in urban habitats; however, ongoing threats and catastrophes may pose a risk to population stability.
