The diamondback terrapin (Malaclemys terrapin) is a brackish-water turtle ranging from Texas to Massachusetts, as well as an isolated population on the island of Bermuda. Louisiana likely holds the most available habitat of any other state for the species (over 650,000 ha of brackish and salt marshes), yet little is known about terrapin distribution and abundance throughout coastal Louisiana. Knowledge is particularly scant in southwestern Louisiana, where only 12 specimen records exist, the most recent record being from 1972. We wanted to determine whether 1) terrapin populations persist in historical collection localities, 2) terrapin populations are present in additional coastal marsh localities, and 3) terrapin abundance differs among sites in southwestern Louisiana. We sampled for diamondback terrapins during 2011–2013 at 16 sites across southwestern Louisiana; all sites were near historical localities or other apparently suitable brackish or salt marsh habitats. We used unbaited fyke nets with 7.6- and 15.2-m leads to capture terrapins and manually searched tidal ponds by airboat. Terrapins (n  =  490) were captured at 13 of 16 sample sites, with terrapin site abundance varying considerably (CPUE mean: 1.06 terrapins per net day; CPUE range: 0–7.06). High terrapin abundance was always associated with large expanses of unimpounded brackish and salt marshes, whereas low abundance was typically associated with smaller marsh sizes, channels, or bayous that no longer connected to the Gulf of Mexico, and the presence of crab traps. All sites with terrapin captures represent either a new locality or the first record for a locality in over 40 yrs. The results of this study underscore the continued need for better distribution and abundance data for poorly studied portions of a species' range, especially those that are of conservation concern.

Mortality incidental to trapping for blue crabs is a primary threat to diamond-backed terrapin (Malaclemys terrapin) populations. Due to sexual size dimorphism in this species, crab-trap mortality is believed to be biased toward smaller adult males and juvenile females. However, a comparison of commercial trap funnel openings and adult female size from a Gulf Coast population suggested that crab-trap mortality is a larger threat than previously thought to adult female terrapins in this population and possibly others.

The diamondback terrapin (Malaclemys terrapin) is a species of conservation concern that has experienced noticeable declines throughout its range. Mark–recapture studies have been conducted on terrapins at Kiawah Island, South Carolina, since 1983, and during the early 1990s, this population began to decline. Our objectives were to evaluate current spatial and temporal variation in survivorship and compare current estimates of survivorship with those calculated from 1983 to 1999 in a previous study. We used an 11-year data set (2003 to 2013) in a capture–mark–recapture analysis to estimate the survivorship of terrapins in 5 creeks. Among creeks, annual survivorship estimates ranged from 61% to 82% with no difference between the sexes. Survivorship was lower than that documented for this population in the early 1990s. Recent anthropogenic habitat modification, such as the construction of docks, roads, and housing developments, as well as activities such as crab-trapping, likely play a role in low annual survivorship. Results from this long-term study are essential for understanding terrapin population status and can inform conservation and coastal ecosystem management.

The chelonian fauna of Togo (West Africa) has been scarcely studied to date. In this article, we review and summarize all available data on the distribution, ecology, and conservation status of the chelonian species of Togo and present a short historical perspective on the development of studies on these reptiles. Overall, 13 chelonian species are found in Togo, 4 being marine, 3 terrestrial, and 6 freshwater. Among the marine species, only 2 of them nest on Togolese beaches (Lepidochelys olivacea and Dermochelys coriacea). Two species (Chelonia mydas and L. olivacea) are still locally common. Concerning the terrestrial and freshwater species, they differed remarkably in terms of their distribution by ecological zone. Cluster analyses revealed the existence of 3 clusters of species, 1 that contains the “forest” species, 1 accommodating the Sudanese savannah species, and a third cluster for the generalist savannah species. The conservation status of the various species and their dissimilarities in terms of threat score categories were assessed through a multivariate model following published work on African chelonian species in general. The results of this model indicate that the potentially most threatened species in Togo are Kinixys erosa, Kinixys homeana, and the 2 Cyclanorbis species (C. senegalensis and C. elegans), with Trionyx triunguis also being possibly seriously threatened. Overall, using the International Union for Conservation of Nature Red List criteria, the concurrent presence of 2 Critically Endangered (K. homeana, C. elegans), 1 Endangered (K. erosa), and several Vulnerable species shows that the chelonian fauna of Togo should be of priority relevance for the competent international agencies.

Change in vegetation structure alters habitat suitability for the threatened gopher tortoise (Gopherus polyphemus). An understanding of this dynamic is crucial to inform habitat and tortoise management strategies. However, it is not known how the choice of the sample grain (i.e., cell size) at which vegetation structure is measured impacts estimates of tortoise–habitat relationships. We used lidar remote sensing to estimate canopy cover around 1573 gopher tortoise burrows at incrementally larger sample grains (1–707 m²) in 450 ha of longleaf pine (Pinus palustris) savanna. Using an information theoretic approach, we demonstrate that the choice of grain size profoundly influences modeled relationships between canopy cover and burrow abandonment. At the most supported grain size (314 m²), the probability of burrow abandonment increased by 1.7% with each percent increase in canopy cover. Ultimately, detecting the appropriate sample grain can lead to more effective development of functional relationships and improve predictive models to manage gopher tortoise habitats.

The Archie Carr National Wildlife Refuge (ACNWR), located along the central east coast of Florida (USA) in the western North Atlantic, hosts one of the largest loggerhead (Caretta caretta) nesting assemblages in the western Hemisphere. Sea turtle nesting activity has been continuously monitored on this beach for > 31 yrs, representing one of the longest sea turtle reproductive data sets in the world. Between 1982 and 2012, an estimated 358,243 nests were deposited on the ACNWR with an estimated annual mean plus 95% confidence interval of 11,556 ± 1,129 nests. This constitutes 25.4% ± 0.8% of the mean annual Florida Index Nesting Beach Survey loggerhead complement. Mean annual clutch size was 113.9 ± 1.4, resulting in a 55.1% ± 4.0% mean annual hatching success rate and a mean emerging success rate of 53.3% ± 3.7%. The only egg-fate that was statistically correlated with emerging success were eggs washed out by erosion. The loss of eggs by erosion was significantly greater during storm and poststorm years, compared with nonstorm years. Among individual first-time nesting females that were measured, mean straight carapace length was 91.2 ± 0.15 cm and mean curved carapace length was 98.2 ± 0.15 cm. These data suggest that the ACNWR supports the greatest loggerhead nest density per kilometer in Florida, underscoring the importance of the ACNWR as one of the most important nesting habitats for loggerhead turtles in the Western Hemisphere.

The crawl to the sea of freshly emerged hatchlings is a critical period in the life cycle of turtles, although it is short compared with their life span. Hatchlings face predation, human poaching, and heat stress. We examined the crawling behavior of hatchling olive ridley (Lepidochelys olivacea) sea turtles at an arribada beach at Ostional, Guanacaste, Costa Rica. We address the following: 1) How long does it take hatchlings to reach the sea? and 2) What factors affect the time required to reach the sea? We were particularly interested in the aspects that increase their success at reaching the sea, and timed hatchling movement on an experimental grid, and for those emerging naturally from nests. Except when the beach was guarded by villagers, black vultures (Coragyps atratus) were present all the time and captured nearly all the hatchlings emerging from first light (0500 hrs) until dark. Overall, the mean time to reach the sea was 19.2 min (SE  =  0.3), mean distance was 27.7 m (SE  =  0.5), and mean time to travel 1 m was 54.2 sec (SE  =  1.0). For all hatchlings (n  =  951), 76% of the variation in time moved/meter was explained by distance to the water, emergence order, type (experimental vs. natural emergence), sand temperature, number emerging/nest, and date. Hatchlings that were picked up (either experimentally or by villagers) moved faster when replaced on the beach than those that were not touched. Many of these same factors explained variation in the time required to crawl the first 5 m from the nest and the time required to reach the water. For all hatchlings the time required to crawl to the water 1) decreased with increasing sand temperature until the sand reached 36°C, when speed increased (hatchlings were heat stressed); 2) decreased with time of day until 0800 hrs, and then it increased as the sand temperatures increased; and 3) generally increased with number of hatchlings that emerged/nest. For hatchlings emerging naturally (n  =  841), emergence order, time of day, temperature (either sand or air), tide, and number of hatchlings that emerged/nest significantly entered models explaining the time required to go different segments of the path to the sea. Hatchlings that emerged first moved faster, and the last to emerge moved slower, than did those emerging in the middle.

Interspecific hybridization has been occasionally reported for various combinations of geoemydid turtles, but genetic consequences of such hybridization have rarely been investigated. We surveyed the hybrid status of 40 individuals from a seemingly hybridizing turtle assemblage in a natural pond in northcentral Honshu, Japan. Analysis of mtDNA sequences confirmed that the parental species of this assemblage were Mauremys reevesii (Chinese three-keeled pond turtle) and Mauremys mutica (Asian yellow pond turtle), neither of which is native to the main islands of Japan, although M. reevesii was naturalized in the area before the 19th century. Extensive examination of pure strain samples of the 2 species yielded 10 morphological and 10 genetic diagnostic characters (allozyme and short interspersed repetitive elements) that were used to determine the hybrid status of the turtles in the assemblage. Morphological examination showed that 19 out of 40 individuals were not different from pure M. reevesii individuals, but the remaining 21 individuals exhibited M. mutica states at 1 to 6 characters, indicating interspecific crosses at a moderate to large scale. In the genetic characters, however, only 2 of the 21 individuals possessed marker alleles of M. mutica at a few loci and all others possessed alleles of M. reevesii only; thus neither pure M. mutica nor F1 hybrids were included in the assemblage. These results suggest that iterative backcrosses with pure M. reevesii have occurred. In the analysis using the genetic hybrid index (GHI), which was defined as the number of M. mutica type alleles over the 10 examined loci, the 2 individuals scored 5 and 2, respectively, and all others scored 0. This discrete distribution of GHI scores negates an assumption of a random mating hybrid swarm but suggests that these two individuals emerged by a different hybridization event, independent from that leading to the many other putative hybrids detected by morphological characters only. Our results suggest that even though the hybrid genotypes rarely prevailed in the population, once introgressed genes were diluted by successive backcrosses, they could have been retained over many generations.

We present information on movement patterns and habitat selection of the endangered Euphrates softshell turtle Rafetus euphraticus (Daudin 1802) from Karkheh Regulating Dam Lake in southwestern Iran. Twelve adult turtles were trapped, fitted with radio-tracking transmitters, and relocated 21 to 51 times between May 2011 and July 2012. The mean linear range size was 2.54 ± 0.83 km, the mean river channel area was 55.35 ± 17.98 ha, the mean minimum convex polygon (MCP) size was 47.49 ± 23.36 ha, and the mean 95% kernel density estimator (KDE 95%) measured 21.75 ± 9.44 ha with a core area (KDE 50%) of 5.74 ± 2.87 ha. Range overlap was generally high; on average, individual MCPs overlapped with those of 7.5 other turtles, individual KDEs with those of 7.3 other turtles, and core areas with those of 5.5 other turtles. Selection of habitat types was not proportional to availability. Study animals preferred shallow-water edge habitats covered with Phragmites australis over all other habitat types.

A key step in generating effective recovery strategies for species at risk is to identify habitat used under a variety of geographic settings. In part attributable to habitat loss and degradation, the Blanding's turtle (Emydoidea blandingii) is considered at risk across most of its range. Because little information for this species exists for the many islands of Georgian Bay, the world's largest freshwater archipelago, we conducted an intensive study on the habitat use of 12 turtles (6 males, 6 females) on a protected island. We used a combination of radio tracking and GPS loggers to determine habitat use during the active seasons of 2011 and 2012. We used aerial imagery to quantify available habitat and used compositional analyses to determine habitat selection. Both sexes used vernal pools and wet forest to move between habitat patches. Females used inland wetlands early in the year and coastal wetlands during the nesting season, whereas males maintained extensive use of inland wetlands during the entire active season. An effective conservation strategy for Blanding's turtles in Georgian Bay must include protection of inland and coastal wetlands, in addition to the surrounding upland matrix and connecting corridors.

Commercial turtle harvest is considered one of the major contributing factors to declines in turtle populations. Few long-term studies have evaluated turtle population response to harvest and little is known about demographic rates for many turtle species. We gathered demographic rates from the literature for snapping turtles (Chelydra serpentina), smooth softshells (Apalone mutica), and spiny softshells (Apalone spinifera), which are harvested in Missouri, and developed deterministic, density-independent, stage-based matrix models to assess turtle population response to plausible harvest rates we estimated from field sampling. Further, we used population modeling to determine annual harvest rates that would result in λ  =  1 for each demographic scenario. We developed one model for snapping turtles and another for both softshell species combined due to the lack of available species-specific demographic data for either softshell species. Using mean demographic rates for survival and fecundity, snapping turtle populations had a growth rate (λ) of 1.023; at minimum demographic rates λ  =  0.891 and at maximum demographic rates λ  =  1.199. When we applied plausible, field-estimated annual harvest rates under mean demographic rates, populations decreased in all instances except when harvesting only juveniles at the minimum harvest rate. At mean demographic rates, annual harvest of both adults and juveniles should be ≤ 2.3% to maintain a stationary population (λ  =  1). For softshell turtles, λ was 0.952 at mean demographic rates, 0.838 at minimum demographic rates, and 1.163 at maximum demographic rates. Under mean and minimum demographic rates, no field-estimated harvest could be sustained, as any annual harvest rate resulted in λ < 1. For both snapping turtles and softshells, harvest was sustainable when demographic rates were at the maximum values, which are highly improbable to occur frequently: annual harvest of 16.3% of both adult and juvenile softshells and 18.6% of adult and juvenile snapping turtles resulted in λ ≥ 1. In both species, elasticity analyses demonstrated that adults, which are the most vulnerable to commercial harvest, were the most important segment of the population demographically. These results corroborate the findings of other studies which indicate that even low annual harvest rates may have detrimental effects on the long-term sustainability of turtle populations at localized scales.

Sea turtle bycatch in commercial fisheries is a serious global problem. An estimated 250,000 loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles are taken each year as incidental catch by the pelagic longline fishing industry. Studies have examined various deterrents for their potential to repel sea turtles from the vicinity of fishing operations; visual deterrents such as shark models/silhouettes and gillnet illumination have shown the most promise. However, given the difficulty of directly observing sea turtle behavior in the wild, laboratory trials are crucial for characterizing the sea turtle response to shark models. The present study examined the response of 42 captive-reared juvenile loggerhead sea turtles to a shark model in a controlled laboratory setting. Loggerheads exhibited defensive behavior toward the shark model, taking significantly more time to bite squid bait beneath the shark model than that for squid beneath a control object (sphere) and bare squid. Also, the turtles approached the shark model less often and exhibited more defensive carapace turns toward the shark model. Although the shark model in this study elicited avoidance behavior in loggerhead sea turtles, further research is needed to identify plausible applications, which would reduce sea turtle bycatch while maintaining target fish catch rates. It may be possible to develop a “Children's Day Koinobori kite” (a three-dimensional kite) in the shape of a shark that would unfurl and “fly” underwater and could possibly clip to main or float lines in commercial fisheries.

We monitored green sea turtle (Chelonia mydas) land basking behavior on Fernandina Island in the Galapagos Islands to determine the potential influence of tide level and weather on the presence and abundance of turtles. Using generalized linear models, we found that both presence and abundance of turtles were related to lower tide levels but that abundance was further related to higher air temperatures, reduced cloud cover, and falling tides; additionally, we recorded more males than have been found in other studies (males  =  41.5% of observations). We hypothesize that haul out during low tide reduces energy expenditure of activities such as coming to the surface to breathe; however, more turtles take advantage of this behavior when conditions such as air temperature and cloud cover are more conducive to physiological benefits such as thermoregulation or acceleration of digestion.

The Arakan forest turtle (Heosemys depressa) is a critically endangered, poorly known chelonian endemic to western Myanmar. Previously known only from the Rakhine ( = Arakan) Hills, we here report a significant northward range extension into the southern Chin Hills, verify the occurrence of H. depressa in Kyauk Pan Taung Wildlife Sanctuary, and present new information on elevational limits, natural history, and folk taxonomy of this enigmatic species.

We report the first specimen-based records of Heosemys spinosa (Gray 1830) from Myanmar, validating earlier assumptions of its occurrence within the country. Our records consist of 5 living H. spinosa examined at Kan Baw Gyi Village in Tanintharyi Region of southern Myanmar. These specimens originated from seasonally inundated lowland riparian wetlands near the village where we examined them. Potential threats to H. spinosa in southern Myanmar include subsistence and commercial harvesting and, most importantly, the widespread conversion of natural forests to oil palm plantations.

Here we provide information on the diet of juvenile green turtles from neritic developmental habitats in the South Atlantic that indicates the existence of a gradual dietary shift from a primarily carnivorous to a primarily herbivorous diet. Linear regression showed a relation between the size of turtles (n  =  22) and the proportion of vegetal matter in the diet, with smaller animals being predominantly carnivorous. We propose 3 hypotheses that could explain these observations.

We investigated the diet of olive ridleys (Lepidochelys olivacea) in Sergipe, northeast Brazil. Stomach contents from 30 stranded animals showed ridleys in the region were benthic carnivorous, consuming mainly crustaceans and fish. Results are valuable to understand the feeding and foraging habitats of this population and to help clarify possible threats in the region.

This study presented information about the semen evaluation of captive male hawksbill sea turtles, Eretmochelys imbricata, based on an extended 15-mo study using the electro-ejaculation technique. In particular, we demonstrated that hawksbill sperm, which is underactive just after ejaculation, was activated by the presence of urine. The findings are useful for developing optimal semen collection techniques for future artificial insemination programs of hawksbill turtles.

Here, we report an incidental observation obtained by an animal-borne video logger of courtship behavior by an adult male green turtle (Chelonia mydas) directed toward an immature green turtle. Our result hypothesized that males may select a mating partner mainly using a visual cue based on size, but without high acuity, so that they can distinguish the size of mature females from that of immature turtles. Hence, male turtles may visualize the objects moving underwater that have the similar size to a mature female turtle as a mating partner, and consequently randomly attempt to court turtles including both immature and mature turtles.

Hatchling marine turtles show a nocturnal rhythm of emergence from the nest. Here, we highlight aspects of the rhythm that are incompletely understood, with special reference to differences in the rhythm's expression among populations as well as its cessation at dawn. We postulate that the rhythm ceases because the hatchlings, as they dig toward the surface, acquire a time sense that suppresses activity if they approach the beach surface too late in the day.