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The CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) data set for the years 1990–2010 were analyzed to depict the main patterns of trade for tortoises and freshwater turtles of wild origin. About 2 million wild individuals were traded over 20 yrs of monitoring, with 48 species (of 335 turtle species in total) belonging to 10 distinct families being regularly traded and over 100 being at least occasionally traded. Most of the traded specimens belonged to the families Testudinidae, Geoemydidae, Emydidae, and Trionychidae (about 93% of trade). The trade of wild individuals reached its peak in the early 2000s, with this pattern being stronger in the Asian region. After the years 2003–2005, there was a substantial decrease in the number of wild exports from the Asian region, with a remarkable growth in the export numbers from the Nearctic region. It is unknown whether the reduction of exported Asian region turtle numbers depended on 1) CITES regulation and supervision or 2) a collapse of the wild populations. There were uneven frequencies of wild turtles traded by biogeographic region, with a higher amount of traded wild turtles coming from Asian and Palearctic regions. There were 107 exporting countries, with Malaysia, the United States, and Indonesia being the most important countries in the trade (each one responsible for over 20% of trade). Overall, there were 66 importing countries, with the most important being the United States (17%), China (15%), and Hong Kong (12%). The conservation implications of the observed patterns are discussed.
Conservation of wood turtles (Glyptemys insculpta) requires improved ecological knowledge near the southern extent of their geographic range. Our objectives were to determine home range sizes and structural habitat characteristics of wood turtles near the southern border of their geographic range in eastern West Virginia. We captured 284 wood turtles (137 males, 88 females, and 59 juveniles) along a 13.7-km reach of river from spring 2009 to summer 2011. Home ranges (95% minimum convex polygons) varied from 0.62 to 36.97 ha; male home ranges tended to be elongated along the river, whereas female and juvenile home ranges encompassed a greater proportion of terrestrial habitat. Low bare ground and rock cover and high vegetative vertical density were structural characteristics associated with the turtles' habitat compared with random plots. Our study provides vital data about home range, movements, and habitat use of wood turtles along the southern border of their range. These data will assist in planning management strategies that will promote the survival and sustainability of the species. We recommend establishing and maintaining riparian zones along waterways bordering agricultural fields to provide essential habitat for the species.
Depredation rates on turtle nests can be very high, resulting in low recruitment to populations. Understanding predator foraging habits and nesting ecology of turtles is essential for the long-term management of threatened turtle species. Cues used by predators to locate wood turtle (Glyptemys insculpta) nests were investigated by creating simulated nests with 1 of 4 treatments: soil disturbance, water with turtle scent, soil disturbance plus turtle scent, or distilled water. Nest predators primarily used soil disturbance cues for locating nests. Additionally, artificial nests with buried chicken eggs were created at varying distances from the river and monitored for predation. Nest predation decreased as nest distance from the river increased. These data can be used to develop strategies for more effective management of this threatened species.
Critical gaps remain in our understanding of many sea turtle nesting aggregations in remote or undeveloped regions. Here, we summarize the first 8 yrs of systematic monitoring of the rookery at Gnaraloo Bay, Western Australia. Diurnal track surveys on this approximately 7-km mainland beach were conducted daily during nesting seasons 2008/09 to 2015/16. The total number of emergences (i.e., nests and failed nesting attempts) recorded per season ranged from 480 to 813 (mean = 679.0, SE = 49.1), whereas the number of nests ranged from 305 to 522 (mean = 376.0, SE = 26.7). Peak nesting activity occurred between mid-December and late January, with approximately 70 emergences and 35 nests recorded on average per week during this time. The majority (97%) of emergences and nests were from loggerhead turtles (Caretta caretta), whereas the remainder (3%) were from green turtles (Chelonia mydas). The number of loggerhead turtle emergences recorded per season declined significantly over the course of the study, wheras the number of nests did not, although we suspect that nest detection errors contributed to the difference between trends. We conducted nocturnal surveys (i.e., direct observations) during parts of seasons 2010/11 to 2015/16 to validate diurnal track interpretations and assess potential biases in the diurnal data set. Diurnal nest counts for loggerhead turtles were underestimates in all seasons but one, with an average nest detection bias of −13.0% (SE = 3.0). After accounting for this bias, we estimate that approximately 405 nests are dug by 85 female loggerhead turtles in the Gnaraloo Bay survey area annually. A similar or slightly lower amount of loggerhead turtle nesting activity occurs at the Cape Farquhar survey area, also located on the Gnaraloo coast; thus, this region contains previously underreported nesting aggregations of this species. The Gnaraloo rookeries may play an important role in the dynamics of the southeast Indian Ocean loggerhead turtle subpopulation and may still be depleted relative to historic levels due to historical predation by introduced foxes. Monitoring, research, and the protection of Gnaraloo beaches are, therefore, critical at this juncture.
The St. Kitts Sea Turtle Monitoring Network (SKSTMN) is a community-based sea turtle conservation organization operating in St. Kitts, West Indies. Four species of either nesting and/or foraging sea turtles have been recorded in the area around St. Kitts, including leatherback (Dermochelys coriacea), green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and loggerhead (Caretta caretta). An open fishing season for sea turtles is active in St. Kitts and Nevis from 1 October through 28 February annually. In 2006, sea turtle fishers in St. Kitts were assessed by the SKSTMN through a survey process to determine the status of sea turtle stocks in the St. Kitts area and to determine the feasibility of developing a local community-based ecotourism project focusing on sea turtles. Based on the results of this survey, the SKSTMN made the decision to develop alternative livelihoods for the fishers to serve as a replacement for the harvest. These included a Sea Turtle Technician Program and a St. Kitts Leatherback Ecotour Package. Prior to the development and implementation of the St. Kitts Leatherback Ecotour Package, a representative survey was prepared and distributed to 3 target groups: local citizens, tourists, and residents. A complete tour package was developed according to the survey results, and the package was offered during leatherback nesting seasons from 2009 to 2014. In 2014, an outcome assessment of the ecotourism initiative was conducted that consisted of electronic survey delivery to a subset of former ecotour participants. These initiatives have resulted in a decrease in the number of sea turtles harvested in St. Kitts annually and have also produced a number of sustainable technician positions for Kittitian citizens on the project.
Nest-site choice in turtles has a demonstrated impact on their fitness. Previous studies of nest-site choice have focused on environmental factors potentially affecting that choice (e.g., temperature, insolation, soil type, or moisture). Observations of nesting of painted turtles (Chrysemys picta) at the Crescent Lake National Wildlife Refuge in the Nebraska Sandhills suggest that females might use olfactory cues (specifically odors of other nesting females) to choose nest sites. We tested this hypothesis indirectly by using the nearest neighbor (nest) distance algorithm in ArcMap 10.1. Our results for nests in 2012–2014 were mixed, with nesting at some sites, in some years, and by some turtles occurring nonrandomly, in very close proximity to previous nests. Preliminary experimental data from 2015 using urine-treated sites in primary nesting areas also suggested that females showed more interest in those sites than sites moistened with equal amounts of water. These data provide some support for the use of nest odor as an important cue for nest-site choice in turtles, but they are insufficient to reject the possibility of the simultaneous use of other fine-scale environmental cues.
Many wild animals are subjected to anthropogenic stressors in the form of direct human disturbances from recreational activities. However, for many species it is unknown how these stressors affect individual fitness and behavior. We tested whether painted turtles (Chrysemys picta), an imperiled freshwater species, would allow closer human approach as measured by the flight initiation distance in the regular presence of humans compared with turtles not exposed to humans. We collected data at a site closed to recreation and at one with regular recreation and found that painted turtles regularly exposed to the presence of humans had significantly shorter average flight initiation distances compared with those at the nonrecreation site. The ability of turtles to tolerate closer human approaches in recreational areas may allow turtle populations to coexist in the presence of some recreational uses.
Sonoran Desert Tortoise (SDT; Gopherus morafkai) populations face threats from habitat loss and fragmentation. Effective management of SDTs in Arizona will require an understanding of the species' age-related habitat needs; however, no published research addresses habitat selection and use in juvenile SDTs. We investigated microhabitat selection of juvenile SDTs in the Mazatzal Mountains in central Arizona. Eleven juvenile SDTs were tracked with radiotelemetry from April 2010 to December 2011. To determine habitat selection, we compared microhabitat characteristics from 117 tracked-tortoise locations to an equal number of random locations during 2 seasons. The summer monsoon (July to September) was the season of greatest SDT activity, whereas winter (December to February) was a season of relative inactivity and hibernation. We found that juvenile SDTs selected enclosed shelters on rocky hillsides with high proportions of boulders and annual vegetation during summer monsoon, and enclosed shelters on steep slopes with a high amount of leaf litter during winter hibernation. Microhabitat selection by juvenile SDTs allowed us to develop a habitat suitability model in a geographic information system (GIS); our model correctly predicted 82% of juvenile tortoise locations in suitable habitat at our site. Results from this study, the first of its kind in the Sonoran Desert, identify key habitat features selected by juvenile SDTs in central Arizona and provide a framework to develop GIS tools to predict juvenile tortoise habitat.
Adult North American tortoises (Gopherus spp.) engage in aggressive interactions with conspecifics when competing for mates and burrows. However, aggressive interactions have not been widely reported in hatchling and juvenile tortoises. We describe aggressive interactions between wild hatchling and juvenile gopher tortoises (Gopherus polyphemus) based on video recordings collected at tortoise burrows. Immature tortoises usually inhabited burrows alone but occasionally shared them. Presence of multiple individuals inside burrows hindered tortoise movements in burrows. Hatchlings or juveniles exhibited overt aggression toward similar aged/sized conspecifics in at least 6 of 13 (46%) encounters, and cameras may have failed to detect aggression occurring inside burrows. Hatchlings and juveniles also exhibited aggressive responses to foreign objects that were similar in appearance to small tortoises. Aggressive behaviors resembled those of adults and included repeated ramming, pushing, biting, and flipping. Young tortoises may respond aggressively to conspecifics at burrows because the presence of additional individuals constrains thermoregulatory and antipredator movements within these important microhabitats. Social interactions appear to play a greater role in the ecology of hatchling and juvenile gopher tortoises than previously recognized.
Although estimates of sea turtle reproductive success are important to quantify population status and effects from threats, published representative values of these rates are rare. Most assessments involving hatching success have taken place as part of experimental analyses that did not spatiotemporally represent a population. To fill this gap, we analyzed an 11-yr time series (2004–2014) of sea turtle hatching and emergence success data for a 7-km stretch of Florida beach backed by mixed suburban and resort/recreational land use. Our analysis examined potential egg-mortality factors associated with the incubation of these nests. The data set included representative sampling of loggerhead (Caretta caretta) nests (n = 2,543, 34.4% of all nests made during the period) and green turtle (Chelonia mydas) nests (n = 972, 44.7% of all nests). Mean (± SD) annual hatching success was 68.6% ± 35.5% for loggerheads and 59.6% ± 39.5% for green turtles, and mean emergence success was 66.6% ± 35.7% for loggerheads and 57.0% ± 39.1% for green turtles. Mammalian predation rates had little effect on overall hatching success trends on our study beach with the sample of predation events (0.3% over 11 yrs) too small to analyze. There were significant effects from tropical storms and hurricanes on hatching success trends throughout the study period, based on negative correlations between hatching success for each species and highest wave height incurred during incubation, mean wave height during incubation, and the number of days that study nests incurred 2 m or higher waves. Hatching and emergence success for each species were lowest during tropical cyclones, which corresponded with an increased number of complete nest wash-outs. Nests within our study site had higher hatching and emergence success rates compared with loggerhead and green turtle nests at other Florida beaches. These assessments of reproductive success are part of a conservation program undertaken at an actively used resort beach, with conservation actions that included vigilance for nest mortality factors and outreach to beachgoers with the aim to promote conscientious behavior during the sea turtle nesting season.
Overwintering behavior of diamond-backed terrapin (Malaclemys terrapin) hatchlings is highly unusual; a substantial percentage of hatchlings leave nests in the fall, travel overland, and rebury themselves on land farther from water. Many aspects of this behavior are poorly documented and conflicting. We tracked 81 newly emerged M. terrapin hatchlings from their nest sites in Jamaica Bay, New York, to their overwintering refugia and until spring/summer emergence. Hatchling M. terrapin used the wrack line only as short-term cover before moving upland and burying themselves in terrestrial refugia. Hatchling refugia depths were variable, up to 10 cm deep, with some vertical movement seasonally. Hatchlings selected winter refugia with relatively high levels of vegetative cover; in this way, overwintering sites differed substantially from temporary refugia. Hatchlings emerged from overwintering refugia between 17 March and 7 July following fall emergence. Our observations better characterize what may be a unique behavior among turtles, but any adaptive value remains obscure.
In the northern Gulf of Mexico, Kemp's ridley sea turtles (Lepidochelys kempii) are incidentally captured by recreational anglers. While sea turtle bycatch is of conservation concern, most studies focus on commercial fisheries, and the number and proportion of turtles affected by recreational fisheries interactions is not known. This study aimed to quantify the proportion of turtles in the Mississippi Sound with evidence of previous interactions with anglers. We analyzed radiographs of hook-and-line captured sea turtles in rehabilitation for number of hooks present, location of hooks, and number of associated hook interactions. The presence of ingested hooks in a number of the rehabilitated L. kempii also allowed us to report on hook transience through observations in rehabilitation, including how transit time related to turtle size, hook size, and position within the gastrointestinal tract. From 2012 to 2015, 882 L. kempii were radiographed. Hooks from prior interactions were found in 12.5% of our total sample. Carapace length was not significantly related to the probability of gear presence, though carapace length did account for 21.9% of the variation of hook sizes in our sample. Transit times were recorded for 50 successfully expelled hooks. Average transit times were 13.50, 8.40, and 4.48 d for the upper, middle, and lower gastrointestinal tract, respectively. Multiple linear regression models showed that transit time was not related to hook or turtle size. This information can be used to inform sea turtle rehabilitation, conservation, and management decisions while highlighting the need for a better understanding of interactions between sea turtles and recreational fisheries.
This work describes the mycelial fungal diversity associated with leatherback sea turtle nests and eggs from Mayagüez-Añasco Bay Coast (MABC), Puerto Rico. Comparisons are made of conditions previous to leatherback nesting season, during leatherback nesting season, and during nest hatching season. Prior to Dermochelys coriacea nesting season, the fungal community along the MABC showed a normal distribution (p = 0.098) by One-Way ANOVA. We found that Aspergillus was the most frequent genus (0.15), followed by Cladosporium (0.09) and Curvularia (0.08). At the time of oviposition, Penicillium was the most frequent isolate (0.15), followed by Cladosporium (0.11), Aspergillus (0.11), and Fusarium (0.07). No fungi were isolated from nesting leatherback's ovipositor samples. During hatching season, fungal diversity was evaluated from the sand of hatched nests and from failed eggs. Fusarium solani was the most frequent isolate (0.57) from hatched nest sand and was the only species isolated from the interior of failed eggs. A strong positive correlation was obtained between fungal abundance and the number of failed eggs in the nests (r = 0.853, p < 0.001). This was the first attempt to study fungal diversity associated with D. coriacea nests and eggs in Puerto Rico.
Fibropapillomatosis (FP) has a complex etiology, involving genetic and environmental factors, and is considered a threat to green sea turtles (Chelonia mydas). The goals of this study were to evaluate phagocytosis and oxidative burst in blood samples of green sea turtles with and without FP. We analyzed samples from 38 specimens (27 with FP) captured at a feeding area in Brazil. No differences were observed between specimens with and without FP regarding leukocyte activity; nevertheless, the analyses revealed there were significant differences among leukocyte populations of animals with FP, lymphocytes and monocytes had higher phagocytic activity than did granulocytes, and lymphocytes had lower oxidative burst activity than did granulocytes and monocytes. This study described an efficient method to assess leukocyte activity through flow cytometry and revealed important characteristics of white blood cells from green sea turtles with FP.
Marine animals including turtles, sharks, and dolphins are bycaught at an alarming rate worldwide, although the extent of this bycatch is rarely quantified. Here, we assess the frequencies of turtle, shark, and dolphin bycatch by fisheries operating artisanal and semi-industrial boats in the Island of Maio, Cape Verde. Among all interviews (n = 139), fishers reported higher shark bycatch (71%) than turtle (32%) and dolphin (9%) bycatch. However, we found no difference in turtle bycatch between artisanal and semi-industrial fishers. Artisanal fishers and semi-industrial fishers caught mostly loggerhead turtle (76%, 48%) followed by the green turtle (6%, 38%). We need further studies that specifically target bycatch and the type of gear used by fishers and verify whether the reported frequencies correspond to actual bycatch rates.
This is the first identification of marine macrophytes consumed by green turtles in Hong Kong, South China Sea: 6 red algae species (Pterocladiella tenuis, Gelidium pusillum, Chondrus ocellatus, Gracilaria chorda, Grateloupia filicina, and Amansia glomerata), 1 brown alga species (Lobophora variegata), and 1 sea grass (Halophila ovalis) were identified. Plastics and other foreign materials were also found in the stomach contents of 2 of the 8 individuals sampled.
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