Freshwater megafauna populations, which are declining worldwide, are well known but often overlooked and understudied compared with marine and terrestrial megafauna. One species of freshwater megafauna is the Suwannee alligator snapping turtle (Macrochelys suwanniensis), which is endemic to the Suwannee River drainage in Georgia and Florida. Several trapping studies have examined M. suwanniensis distribution, body size, and population structure, but little information exists regarding its population status. The objectives of our study were to 1) estimate population size, 2) estimate apparent survival, and 3) model population growth rates (k) by conducting a capture–mark–recapture study of M. suwanniensis in the Suwannee River in Florida. From 2011 to 2013, we repeatedly sampled 12 randomly selected 5-km sites along the Suwannee River for M. suwanniensis using baited hoop-net traps. We captured 126 individuals and had 29 recaptures. Both adult males and adult females had very high apparent survival (0.99), whereas juveniles had lower apparent survival (0.32). We estimated a population density of 6.6 turtles/river km, indicating a population of 1709 (95% CI, 1205–2694) M. suwanniensis from the town of White Springs to the upper limit of the estuary in the main stem of the Suwannee River (approximately 259 river km). We constructed 2 postbreeding census matrix population models for M. suwanniensis and incorporated parameters from this study and from the literature. Both matrix population models suggested a slightly decreasing population (k = 0.99), but because of the uncertainty around our estimates, we consider the population trend to be unclear. Elasticity analysis revealed that k was most sensitive to changes in adult survival compared with other model components. This is a conservation concern because adult M. suwanniensis may be incidentally killed by fishing gear. Our study was short-term, and our analyses had limitations; therefore, we recommend future areas of research, including long-term population monitoring.

The Khorat snail-eating turtle (Malayemys khoratensis) is a recently described (2016), poorly studied freshwater turtle known from the Khorat Plateau in Thailand and a small area near Vientiane, Lao People's Democratic Republic. We investigated the occurrence and natural history of M. khoratensis during field surveys of Xe Champhone Ramsar Site (XCRS) and Nong Louang Wetland Complex (NLWC) in Savannakhet Province, and also examined museum specimens and published and unpublished photographs of Malayemys spp. from Lao. Our field surveys confirmed the occurrence of M. khoratensis in the XCRS and NLWC, where populations remain subject to harvest at levels unlikely to be sustainable. We examined 7 museum specimens from Vientiane, Savannakhet, Khammouan, and Champasak provinces. Museum specimens from Vientiane, Savannakhet, and Khammouan provinces were referable to M. khoratensis. Published photographs confirm the occurrence of M. khoratensis in Vientiane Province, and Malayemys subtrijuga in Champasak Province. Collectively, our records extend the geographic distribution of K. khoratensis by > 300 km from previously reported localities. We posit the existence of a biogeographic barrier in southern Lao and adjacent Thailand that separates the allopatrically occurring M. khoratensis and M. subtrijuga.

Immature hawksbill turtles were studied in Jardines de la Reina Archipelago, the principal area of distribution for this species in Cuban waters. Hawksbill areas of occurrence, size composition, scope of movement range, and somatic growth rates are presented. A total of 496 individuals were caught while diving or with nets at depths of 0.5–2.5 m. Differences in size distribution were observed among survey areas within the Jardines de la Reina Archipelago. Mean curved carapace lengths were 35.6 ± 9.6 cm and 59.6 ± 7.7 cm for hawksbills captured in the external and internal cays, respectively. Forty-two individuals were recaptured between 1 and 4 times at intervals averaging 554.9 d. For recaptured turtles, 91% were encountered within < 1 km of their original capture location. Our findings indicate that the benthic habitats of Jardines de la Reina Archipelago are favorable for the recruitment of juvenile hawksbill turtles transitioning from pelagic habitats. The data also show that hawksbills are distributed throughout the Jardines de la Reina Archipelago study region, and that coastal foraging areas within this region host small, postpelagic juveniles as well as larger immature hawksbills that have been resident for extended periods.

Evolutionary theories predict major differences in life-history trait values of long- and short-lived organisms. Such comparisons have not been possible for chelonians because no short-lived turtle was known until research revealed that chicken turtles (Deirochelys reticularia; DR) have a maximum longevity of 21 yrs. Life-history trait values of DR females are 1) age at maturity of females = 5–6 yrs; 2) clutches per season = 1.6; 3) annual fecundity = 6–8 female eggs per female; 4) average juvenile survivorship from age 1 to maturity = 0.60; and 5) low average annual adult survivorship = 0.66. We compared DR with the very long-lived Blanding's turtles (Emydoidea blandingii; EB) in Michigan. Over 14 yrs with no mortality (the minimum age at maturity of EB), the maximum potential fecundity produced by a single female embryo and her mature female offspring was 5 female eggs for EB and 1040 eggs for DR. Comparisons of life table output for approximately stable populations of DR and EB resulted in cohort generation times of 7 and 37 yrs, respectively. The life-history prediction that short-lived organisms should produce smaller offspring was not supported. Average wet mass of eggs is 10 g (8.4–11.3 g) for DR and 12 g (10–14 g) for EB; and average wet mass of hatchlings is 7.3 g (6–9 g) for DR and 9.3 g (6–13 g) for EB. Both differences are smaller than expected based on the difference in longevity. Short-lived female DR have an unusual tactic of investing in high fecundity and making substantial body size-specific investment in large eggs, which may reflect why juvenile survivorship had greater influence on population change rates than did adult survivorship. In contrast, adult survivorship had the greatest influence on population change rates of EB. Comparison of cohorts of 1000 female DR and EB hatchlings highlights the differences in life histories of short- and long-lived turtles: all DR would be dead by the time the last female EB had reached maturity at 21 yrs of age.

Dermatemys mawii is a critically endangered freshwater turtle endemic to Central America. In the wild, these turtles are thought to be wholly herbivorous as adults and feed on a variety of vegetation; however, no studies have quantitatively assessed potential dietary differences based on biotic and abiotic factors. The purpose of our study was to describe and quantify the wild diet of D. mawii and assess differences based on habitat, maturity, and sex. We evaluated the stomach contents of 66 turtles legally harvested by local hunters for personal consumption throughout the country of Belize. Percent volume (by displacement) and percent frequency of each stomach item were used to calculate an index of relative importance (IRI). One algal and 6 plant families contributed to an overall diet composition consisting of leaves, flowers, stems, seedpods, seeds, and fruit. Rocks and invertebrates were also consumed, although we believe these to be incidental consumption. The leaves of the riparian tree Inga edulis were present in 73.1% of turtle stomachs and accounted for almost half of the total volume of all stomach contents combined. We used Spearman rank correlation coefficients to test the null hypothesis that there was no correlation in the rankings of stomach items (i.e., there were differences) when comparing turtles by habitat, age, and sex. There were significant differences in the ranking of food items between river and lagoon habitats, with lagoon turtles relying heavily on the algae Nitella sp.; however, the stomach contents from both habitats were equally diverse (H_rivers = 1.68, H_lagoons = 1.64). There were no differences in IRIs between adults and juveniles or between males and females. Our results emphasize the importance of habitat in D. mawii diet selection and the importance of leaves from riparian plants species that are shed into their aquatic habitats.

In 2015, nearly 4000 critically endangered Palawan forest turtles (Siebenrockiella leytensis) were confiscated on their native island of Palawan in the Philippines after being illegally harvested for the international wildlife trade. Local conservation biologists and an international team of veterinary and husbandry personnel evaluated, treated, and repatriated the majority of turtles (88%) over a 3-mo period. Common pathologic findings included ophthalmic, dermatologic, musculoskeletal, and gastrointestinal lesions, including keratitis, osteomyelitis of the shell and digits, pododermatitis, and colonic nematodiasis. Hemogram results indicated severe leukocytosis in many individuals. Specimens for genetic analysis and molecular diagnostics were archived, and several intact carcasses were established as museum specimens. International collaboration may be required to ensure the confiscation and survival of illegally traded endangered wildlife, with ongoing efforts toward enhancing the law enforcement, husbandry, and veterinary capacity of range country personnel.

Although commercial hook and line fisheries pose a well-documented and significant threat to worldwide sea turtle populations, recreational hook and line fisheries remain understudied. This article describes information from sea turtle bycatch reported from interactions in the recreational hook and line fishery, as well as survey results from recreational anglers in Virginia from 2014 through 2018. Reports of interactions increased annually during the study with Kemp's ridley sea turtles (Lepidochelys kempii) reported most frequently (n = 162), followed by 45 loggerheads (Caretta caretta), 6 green turtles (Chelonia mydas), and 39 unidentified sea turtles. Commonly encountered bait types were similar between surveyed anglers and bait used during turtle interactions, with significantly more squid bait noted during turtle interactions (51%) than used by surveyed anglers (29%) (χ² = 41.32, p < 0.0001). Additionally, bloodworms and artificial bait were encountered comparatively less frequently during turtle interactions. Overall, interactions with the hook and line recreational fishery in Virginia appear opportunistic and involve otherwise healthy animals, presenting limited means for mitigating sea turtle bycatch. In the absence of regulatory oversight of bycaught sea turtles in the recreational fishery, mitigating injury from these interactions through targeted outreach provides a short-term solution to reducing the severity of these inevitable interactions.

Long Island Sound and the Great Peconic Bay (New York) contain southern barrier lagoons and eastern bays and are known habitats for foraging juvenile populations of sea turtles during summer months. Every year, sea turtles strand throughout these areas due to climate-related cold snaps that typically occur in the late fall and lead to cold-stunning, a physiological temperature shock similar to hypothermia that renders turtles unable to swim and prone to wash up onto beaches. Cold-stunning events in this area tend to last longer than a few weeks and typically affect juvenile Kemp's ridley (Lepidochelys kempii), juvenile green (Chelonia mydas) and subadult loggerhead (Caretta caretta) sea turtles. The New York Marine Rescue Center, formally known as the Riverhead Foundation for Marine Research and Preservation, is the sole rehabilitation facility for cold-stunned sea turtles in New York and responds to the second-largest number of cold stuns in the Greater Atlantic Region, which encompasses marine ecosystems from Maine to North Carolina. Since 1998, a total of 510 sea turtles have been recovered from New York state waters or beaches between the months of October and February. Of these 510 cases, 5 individuals restranded under similar conditions following rehabilitation and release, resulting in 505 distinct sea turtles stranding due to cold-stunning. These 505 cold-stunned sea turtles were composed of 3 different species: 281 L. kempii (56.0%), 174 C. mydas (31.3%), 48 C. caretta (9.5%), and 2 hybrids (0.4%). Over the course of 22 yrs, stranding frequency varied from 3 to 85 turtles per season, with an average of 23. However, a large increase in stranding numbers began in 2007; average stranding numbers from 1998 to 2006 were 7 per season, increasing to 34 per season from 2007 to 2019. Multiple factors are likely contributing to the increase in stranding/rescue frequency such as the gradual warming of northern waters (which may entice turtles farther north and prevent their timely southern migration), development of a free public outreach program targeted at educating patrons about local sea turtle populations, and implementation of an effective beach patrolling system. More efficient management of patrolling efforts has contributed to the quick response time and resulting increase in live turtle rescues. In addition, modification and enhancement of in-house treatment protocols have contributed to the upward trend of successfully rehabilitated cold-stunned turtles. Understanding historical cold-stun trends will allow local and national organizations to identify needs and allocate funding for conservation initiatives of endangered Atlantic sea turtle populations.

At-sea mortality information is important for understanding the magnitude of threats to protected sea turtle species. When a sea turtle dies, it typically sinks, starts decomposing, and will eventually float to the surface if the carcass remains intact and enough internal gases accumulate. However, few data are available regarding the rate and duration of these processes to allow estimation of time since death once carcasses are recovered. Twenty-seven Kemp's ridley (Lepidochelys kempii) and 15 green (Chelonia mydas) sea turtle cold-stunned carcasses were placed in wire mesh, weighted cages at varying water depths (10–40 m) and temperatures (18.5°C–28.7°C) in the northern Gulf of Mexico from June 2018 to October 2019. Cameras and temperature-depth-orientation recorders were used to document decomposition progression and carcass buoyancy. Decomposition rate was measured using corrected accumulated degree hours and values of observed time-to-float were compared with predictions based on laboratory and field experiments in previous research. Overall, carcasses did not float when deployed in waters > 30 m when temperatures were < 22°C and carcasses tended to float sooner in ≤ 20 m depths, especially if bottom temperatures were > 24°C. Green sea turtle carcasses floated in a variety of environmental conditions, but onset of positive buoyancy was not very predictable. Buoyancy of Kemp's ridley sea turtle carcasses was inconsistent, but float times were fairly predictable. We did not identify the exact depth at which sea turtle carcasses cannot generate enough gases to float, but that depth is likely very close to 40 m. Carcasses that became buoyant in ≥ 30 m depths tended to float for < 24 hrs before sinking again and, therefore, it is unlikely that they have enough time to drift to shore. This information enhances our understanding of the likelihood of carcasses washing ashore and can be incorporated into carcass backtracking analyses to facilitate identification of mortality causes.

Invasive red foxes (Vulpes vulpes) are a serious conservation issue for Australia's freshwater turtle species, including the endangered Bell's turtle (Myuchelys bellii). As many as 96% of Australian freshwater turtle nests may be depredated in a season by foxes. Current methods of turtle nest protection rely on early detection of nesting activity, followed by nest-specific structures to prevent predation. An alternative method to provide protection against fox raiding was tested: nesting refuge structures based on a design successfully used in the United States to protect diamondback terrapin (Malaclemys terrapin) nests. Six wood and chicken wire structures were placed at different sites beside large riverine pools on the Macdonald and Gwydir rivers, northeastern New South Wales, Australia, in the summers of 2019–2020 and 2020–2021. Sites were chosen for known previous nesting activity or presence of mature females, and each structure was placed in typical Bell's turtle nesting habitat at known nesting sites. Prior to placement, the soil was tilled with a rotary hoe to make the interior of the structure more enticing as nesting habitat, because Bell's turtles had been previously seen to nest in disturbed soils. Although females did approach the structures and in one case entered, no females were recorded nesting inside. Further, severe flooding in both years damaged and/or displaced 4 of the 6 structures. Rigid nest protection structures were therefore not shown to be an effective nest protection method for this species, despite their success in other regions for other species. Negative results such as these are important for conservation studies because they guide conservation efforts away from expending limited resources on ineffective methods and strategies.

Currently, the genetic population structure of only 3 green turtle, Chelonia mydas, rookeries is used to categorize the Eastern Caribbean grouping of the South Atlantic distinct population segment. Tissue samples were collected from 66 nesting green turtles on the East End beaches of St. Croix, US Virgin Islands from 2012 to 2015, and we sequenced ∼ 800 base pairs of the mitochondrial DNA (mtDNA) control region to characterize the genetic structure and test for differentiation with the adjacent Buck Island rookery. The haplotypes CmA5.1, CmA5.2, and CmA3.1 were identified on the East End beaches. Results of pairwise tests for differentiation were mixed, with frequency-based F_ST failing to detect differentiation at the p < 0.05 threshold (F_ST = 0.01148, p = 0.18503), and an exact test indicating significant differentiation (p = 0.02146). The detection of CmA3.1 and not CmA16.1 within the East End beaches adds to the haplotype diversity previously observed in the Eastern Caribbean region and suggests that genetic diversity has been underestimated in previous studies. Further investigation including mitogenomic markers and nuclear DNA analyses would provide additional clarity as to the population structure in this region.

In the southern half of peninsular Florida, where longleaf pine (Pinus palustris) sandhill communities are scarce, gopher tortoises (Gopherus polyphemus) primarily occupy mesic flatwoods and Florida scrub habitats that appear suboptimal due to poorly drained soils in flatwoods and low forage abundance in scrub. Tortoise populations persist in these habitats, but their demography is poorly understood. We used burrow size-class distributions to assess population age structure in flatwoods and scrub habitats. In addition, we monitored tortoise nests and burrows with automated cameras to assess nest fate and visitation by predators. Burrows in flatwoods were strongly skewed toward adult size classes, suggesting low juvenile recruitment, which may be due to poor nest success caused by surface flooding or saturated soils. Size class distributions in scrub were also skewed but were closer to the expected range for a long-lived species with slowed growth following maturity. Rates of predator visitation did not differ between habitats but nests in flatwoods were inundated by heavy rains. More research is needed to clarify the demographics of gopher tortoises in the southernmost extent of their range. However, we suspect that some negative demographic consequences of suboptimal conditions may be offset by the warm climate in southern Florida, which may lengthen the growing season, promoting faster growth and earlier age at first reproduction that could boost population growth.

Although ultrasonographic examination of the blood vessels of sea turtles has been a helpful tool in the clinical setting, there is a paucity of data on the normal cervical echoanatomy of green turtles (Chelonia mydas); such information could be valuable for conservation-focused efforts at rehabilitation facilities. We studied the echoanatomical features of the major blood vessels of the neck of juvenile green turtles by gross dissection of 5 deceased turtles and by ultrasonographic examination of 11 healthy animals. The external jugular and the vertebral veins were superficial (< 1.5 cm) and presented an echogenic and turbulent pattern of blood flow in B-mode examination; carotid arteries lied deeply within the neck (> 1.5 cm) and exhibited a laminar blood flow characterized by a parabolic velocity profile as determined by Doppler sonography.

The alligator snapping turtle (Macrochelys temminckii) has been proposed as a Threatened species under the US Endangered Species Act and is considered Vulnerable by the International Union for the Conservation of Nature. To provide additional markers for conservation genetic studies, we identified 60 potential microsatellite loci, with 38 being polymorphic in M. temminckii, as well as successful cross-amplification of 12 and 32 polymorphic loci in the Suwannee alligator snapping turtle (M. suwanniensis) and Eastern snapping turtle (Chelydra serpentina), respectively. These loci will be useful in genetic studies associated with informing future management decisions for M. temminckii and the other species of Chelydridae.

We assess all the records of olive ridley turtles (Lepidochelys olivacea) in an exhaustive review of multiple data sources between 1977 and 2018 in Venezuela. We compiled 35 records of olive ridleys in the country. Our findings confirm the almost year-round presence of this species in Venezuelan waters.

Se evaluaron todos los registros de tortuga guaraguá (Lepidochelys olivacea) disponibles a través de una revisión exhaustiva de diversas fuentes, la cual comprendió entre los años 1977 y 2018 para Venezuela. Se compilaron un total de 35 registros de tortuga guaraguá para el país. Las evidencias confirman la presencia casi permanente durante todo el año de la especie en aguas territoriales venezolanas.