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We present updated accounts on the status and distribution of all known species of freshwater turtles in the Philippines, including information on taxonomy, natural history, exploitation, and conservation status. Six species of native nonmarine turtles (Dogania subplana, Pelochelys cantorii, Cuora amboinensis, Cyclemys dentata, Heosemys spinosa, and Siebenrockiella leytensis) are recognized from the Philippines, 2 of which are trionychids and 4 are geoemydids. One of these (S. leytensis) is an endemic species. There is some evidence to suggest that Philippine populations of P. cantorii, C. amboinensis, C. dentata, and H. spinosa may warrant further taxonomic study. The fauna also includes 3 introduced species (Pelodiscus sinensis, Trachemys scripta elegans, and Chrysemys picta). Pelodiscus sinensis, D. subplana, C. amboinensis, and S. leytensis feature prominently in the domestic food and pet trade. Preliminary information indicates that these species are also illegally exported to supply international animal markets. The lack of basic information on the natural history of freshwater turtles in the Philippines stands as an obstacle to the implementation of effective conservation and management measures. We recommend that a national program for Philippine freshwater turtles be established to address priorities for research, conservation, and management of this threatened and poorly studied faunal assemblage.
The nesting biology of loggerhead turtles, Caretta caretta, on Dalyan beach, Turkey, was studied during the 2004 and 2005 nesting seasons. In addition, we analyzed nesting trends over 19 consecutive years, from 1987 to 2005. A total of 711 emergences occurred in 2004 and 605 emergences in 2005, of which 223 (31.4%) and 221 (36.5%) nests were deposited, respectively. Mean nesting densities were 47.5 nests km−1 and 47 nests km−1 in 2004 and 2005, respectively. Of the overall nests, 424 (95%) were excavated and 32,339 eggs were counted. Of these eggs, 19,947 (61.7%) hatchlings had come out and 18,607 (93.3% of hatchlings) of them were able to reach the sea. We recorded a total of 3688 nests on Dalyan beach during 19 consecutive years with a mean of 194 nests per year. There were also strong annual fluctuations in the number of nests, which ranged from a minimum of 57 nests (in 1990) to a maximum of 286 (in 2002). No trend in the number of nests over the 19-year period was seen (95% CI −2.7% to 6.7% change per year). The lack of increase was a surprising result when considering the long-term conservation efforts on the beach; although, a similar case was reported in Laganas Bay, Greece. High interannual fluctuations could obscure trends as stated in previous studies.
We studied the population structure and growth of western pond turtles (Actinemys marmorata) at Vandenberg Air Force Base along the coast of central California in April 1995 and June 1996. We captured 179 individuals (115 males, 27 females) from 7 ponds during 26 days of trapping. Many turtles were adult-sized, but based on scute annuli, 74% were < 10 years of age, including many 2- to 3-year-olds. This population structure likely was due to a relatively fast growth rate, especially compared with closely related aquatic turtles in eastern North America. Mean clutch size was 5.2, but 66.7% of females were gravid, and 1 female produced 2 clutches. These reproductive data are similar to those reported for other populations in the southern portion of the species' range. Females reached reproductive maturity as early as 4 years of age. The relatively mild temperatures of California's Mediterranean climate, especially when compared to the seasonal extremes in more continental and northern regions of North America, may explain the different growth rates and population characteristics of freshwater turtles from these 2 regions of North America.
We investigated the biodiversity, exploitation, and conservation status of turtles in the Tonle Sap Biosphere Reserve (TSBR) of Cambodia from June 2000 through October 2001. We confirmed the occurrence or former occurrence of 4 native species of turtles (Batagur baska, Cuora amboinensis, Heosemys annandalii, and Malayemys subtrijuga) in TSBR and discuss the possible occurrence of 4 others, including 2 native species (Amyda cartilaginea and Pelochelys cantorii) and 2 exotics (Trachemys scripta and Pelodiscus sinensis). Large numbers of turtles were being unsustainably harvested from TSBR at the time of our study. Most harvested turtles were destined for urban markets in Cambodia and international wildlife markets in Vietnam and southern China, with very few kept by fishermen for household consumption. We regard any attempts to eliminate the subsistence harvest of turtles as impractical in Cambodia but recommend a complete ban on the extraction of turtles and other wildlife resources from the 3 core areas of TSBR. Incidental to our investigation of turtles in TSBR, we collected data on sexual size dimorphism and reproductive biology of M. subtrijuga. Our findings indicate that female M. subtrijuga are larger than males, and females may construct underwater nests as floodwaters begin to recede in the early dry season.
Aquatic biologists throughout the United States use fyke nets to sample fish. Often, these nets have high turtle bycatch and mortality rates, especially when set in extreme environmental conditions. Because a previous study found increased turtle mortality using Wisconsin-type fyke nets, we designed and tested a bycatch reduction device (BRD) for this net type and investigated its ability to reduce turtle bycatch without affecting fish capture. Over 68 net-nights, the BRD significantly reduced turtle bycatch with no significant decrease in fish quantity or richness when compared to a control fyke net with no BRD. We argue that aquatic biologists and managers should consider turtle mortality when sampling fishes and other aquatic organisms. We also suggest that further studies be conducted to develop BRDs for all passive freshwater sampling nets. Further, BRDs that have already been designed and tested and appear effective at reducing turtle bycatch without significantly affecting fish catch, such as ours, should be implemented in freshwater fisheries methodologies. This is the first known BRD developed for freshwater trap nets.
Since 1993 the Venezuelan government has implemented an intensive management program aiming to increase the population size of the endangered giant South American turtle (Podocnemis expansa). Including nest relocation and a year of captive rearing of hatchlings, the program affects the main Venezuelan P. expansa population, located in the middle Orinoco River. Although the program seems to be increasing recruitment of new individuals into the population, the effects of such nest relocation on long-term fitness-correlated parameters have not been addressed. Here we measured posthatching mortality, presence of morphological abnormalities, first-year body growth rate, and locomotive performance of juvenile turtles subjected to this management program. Nest relocation had a profound influence on juvenile P. expansa turtles, affecting their mortality, morphology, body growth rate, and locomotive performance. Transplanted clutches showed higher hatchling mortality and higher incidence of morphological abnormalities, though higher growth rates than nontransplanted clutches. Likewise, juvenile turtles coming from nontransplanted clutches appeared to run faster than those coming from transplanted nests. Clutch manipulation seemed to be responsible for the occurrence of morphological abnormalities and the increased mortality. Higher temperatures, on the other hand, may be the cause for the observed higher body growth rates in transplanted nests. Our results suggest that future management efforts minimizing the effects of clutch manipulation will not only prevent clutch losses but also enhance the long-term survival of neonates.
The Euphrates softshell turtle, Rafetus euphraticus, is one of the least known species of the Trionychidae. It is found only in the Euphrates and Tigris rivers and their tributaries in Iran, Turkey, Syria, and Iraq. Its range in Iran is limited to Khuzestan Province. In the course of this study (February 2002–June 2005), 16 visits were made to habitats of the species along the Karkheh, Dez, and Karoon rivers and their tributaries in Khuzestan. During these visits 25 specimens were observed and habitat characteristics and threat factors were recorded. Habitat destruction, pollution, and fisheries interactions (intentional killing) are the main threats to the survival of this species in Iran.
Whole blood and keratin mercury concentrations, complete blood cell counts, and plasma biochemical health profiles were evaluated in 31 juvenile cold-stunned Kemp's ridley turtles (Lepidochelys kempii) from Cape Cod, Massachusetts. In addition, plasma copper, zinc, selenium, and cadmium concentrations were measured for 16 of these turtles. Liver mercury concentrations were measured for 6 turtles that were dead upon acquisition or died during rehabilitation. Concentrations of 18 organochlorine pesticides were measured in plasma of 18 live turtles, and liver, kidney, fat, and brain of 3 deceased turtles. Metal levels were generally similar to those previously published for sea turtles, with mean values (wet weight) of 24 ng/g for blood mercury, 67 ng/g for liver mercury, 389 ng/g for keratin mercury, 690 ng/g for plasma copper, 2290 ng/g for plasma zinc, and 490 ng/g for plasma selenium. Cadmium was not detected in any sample. Organochlorine levels were generally low in comparison to values published for cold-stunned juvenile Kemp's ridley turtles in the 1980s. Several significant correlations between metal levels, hematology, and plasma biochemical health parameters were detected; however, the cause of these correlations could not be determined. This study demonstrates that Kemp's ridley turtles may be exposed to contaminants at a young age. Further investigation of the sources and effects of contaminants in juvenile sea turtles is warranted.
We investigated the distribution and conservation status of Indotestudo forstenii, Leucocephalon yuwonoi, and Cuora amboinensis in northern Sulawesi, Indonesia during 2005–06. Village interviews suggest that I. forstenii and L. yuwonoi are more widely distributed than available records indicate. We verified the occurrence of I. forstenii at five heretofore unreported localities in Central and North Sulawesi, including xeric hills above the Palu Valley and sites adjacent to Lore Lindu National Park, and local villagers reported encounters in Panua Nature Reserve. Sexual size dimorphism was not evident in our sample (n = 103) of I. forstenii. We were unable to locate wild populations of L. yuwonoi, but interview data suggest that this endemic species might occur in Bogani Nani Wartabone National Park and Panua Nature Reserve. Among the L. yuwonoi we measured (n = 150), males were larger than females; large body size may give males an advantage in intraspecific dominance contests. Cuora amboinensis remains common in northern Sulawesi where it occurs in a variety of wetland habitats. Subsistence harvesting of turtles appears minimal in northern Sulawesi owing to a cultural bias against consuming turtle meat. We found little evidence of commercial exploitation of turtles in North Sulawesi and Gorontalo; however, a modest but increasing number of turtles are being harvested in Central Sulawesi to supply local ethnic Chinese, and international pet, food, and medicinal markets. Future conservation efforts should seek to verify the occurrence of endemic chelonians in protected areas and develop management plans to insure the survival of these populations.
Little is known about the impact of the Indian Ocean tsunami on wildlife populations. Five species of sea turtle nest on the beaches of southern Sri Lanka; initial reports after the tsunami revealed damage to nesting beaches, hatcheries, and adult foraging habitat. We show that, in the year after the tsunami, the number of adult females returning to nesting beaches at Bundala National Park remained almost unchanged from previous years.
The only known skull of the extinct Madagacan giant tortoise Dipsochelys abrupta is redescribed. It is similar to the other extinct Madagascar tortoise, Dipsochelys grandidieri, differing in the width of the vomer, in having a ridge on the occipital condyle, and in lacking diverging articular condyles of the quadrates.
I investigated the effect of predators on hawksbill reproduction and evaluated the effectiveness of protecting nests using plastic net at a beach in Qatar along the Arabian Gulf. Predators such as feral cats and the fox, Vulpes rueppelli, were present at very high densities. Nests not protected by plastic net were 100% depredated to some extent; > 80% were completely destroyed.
We studied dispersal of Phrynops geoffroanus in a polluted urban stream in central Brazil. Dispersal distances ranged from 0.0 to 115.0 m after 72 hours and home range size ranged from 0.04 to 0.12 ha. Turtle dispersal for adults and juveniles was accentuated in the first 3 hours with a predominantly upstream movement. Turtle size was significantly related to dispersal distance after 48 hours. Results suggest that the low dispersal rate and the small home range size reflect food supplementation provided by a polluted habitat.
The International Union for Conservation of Nature and Natural Resources Red List considers Batagur baska regionally extinct in Myanmar owing to the paucity of recent records. We conducted field surveys in coastal regions of Myanmar during 2004 and verified the occurrence of small populations of B. baska at scattered localities in Mon State, and Tanintharyi and Ayeyarwady Divisions. We attribute the continued persistence of these populations to a combination of local religious beliefs that discourage the capture of turtles and areas of armed conflict between government forces and Mon insurgents where fishermen can venture only at great personal risk.
Red-eared sliders are listed as exotic, naturalized, and invasive in Bermuda; however, there is no published information regarding their ecological status. This paper discusses abundance, distribution, and the potential impact these feral pond turtles have on this remote oceanic island.
The global trade in tortoises of the genus Testudo was reviewed by using compiled import data from Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) for 1975–2005. A total of 58 importing and 112 exporting countries were recorded as being involved with the Testudo trade. Turkey, the former Soviet Union, the former Yugoslavia, Morocco, Uzbekistan, Russia, and Ukraine accounted for 81% of the recorded exports; whereas, the United Kingdom, Germany, and the United States dominated the import market with 67% of the individuals. Testudo horsfieldi accounted for 48% of the exports, followed by Testudo graeca (37%) and Testudo hermanni (13%). A total of 2,062,289 individuals were traded internationally, and of these, 99% were live animals. Of the animals from known sources, 67% were from the wild, and 16% were allegedly captive bred; the source of 70% of all declared trade animals was unknown.
Several new localities for the Tehuantepec slider, Trachemys grayi, are documented in coastal Oaxaca, Mexico. A problematical locality in coastal Oaxaca is discussed. Trachemys grayi is the largest representative of the genus in Mexico, and appears to be highly threatened.
The purpose of this study was to quantify seasonal variation in basking habits within 2 syntopic species of map turtles (Graptemys pseudogeographica kohnii and Graptemys ouachitensis sabinensis) in eastern Texas. Basking surveys were conducted twice per week from January 2005 to January 2006 along a 1.5-km transect of the Sabine River in Smith County. During this period, 312 observations of male and 178 observations of female G. pseudogeographica kohnii were recorded, while 2761 observations of male and 1334 observations of female G. ouachitensis sabinensis were made. Basking activity peaked in March (G. pseudogeographica kohnii) and May (G. ouachitensis sabinensis) with a peak of lesser magnitude for both species occurring in November. Within G. ouachitensis sabinensis, significantly more males than females were recorded basking throughout the year; however, in G. pseudogeographica kohnii significantly more males were recorded only during spring and fall.
We investigated the cultural exploitation of nonmarine turtles in Sarawak State, Malaysia. Turtles are primarily used for food, and the Asian softshell turtle, Amyda cartilaginea, appears to be the most desirable species. Other local demands include the pet trade, which involves both local and exotic species of turtles.
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