Depot fatty acid composition in immature green turtles (Chelonia mydas) residing at two near-shore foraging areas in the Hawaiian Islands

The lipid content and fatty acid composition of depot fat were determined for 58 immature green turtles (Chelonia mydas) residing at two near-shore foraging areas, Ahu-O-Laka, located in Kaneohe Bay on Oahu, and Kiholo Bay located on the island of Hawaii. Benthic flora at Kiholo was limited to a single algal species but included algae and seagrass at Ahu-O-Laka. Turtle straight carapace length ranged from 38.6 to 59.2 cm, suggesting that the sample set included new recruits to up to 12-year residents. Fatty acid data were analyzed using principal components analysis (PCA). PC1 accounted for over 50% of the variance. Turtles were generally delineated along PC1 by the length of time on benthic foraging grounds, with high (>0.75) negative loadings for the fatty acids 22:6n-3, 7M7H, t16:1n-10, 15:0, and 17:0 associated with relatively new recruits (suggesting a pelagic dietary source for these fatty acids) and high positive loadings for 12:0 and 14:0 associated with long-term residents. PC2 separated turtles primarily by capture location, with high positive loadings for 18:2n-6 and 18:3n-3 [the primary seagrass polyunsaturated fatty acids] associated with the Ahu-O-Laka turtles. Fatty acid profiles of turtles from both locations differed substantially from those of their benthic diets, suggesting considerable modification of dietary fatty acids and de novo biosynthesis.     

Fibropapillomatosis in stranded green turtles (Chelonia mydas) from the eastern United States (1980-98): trends and associations with environmental factors

We examined data collected by the US Sea Turtle Stranding and Salvage Network on 4,328 green turtles (Chelonia mydas) found dead or debilitated (i.e., stranded) in the eastern half of the USA from Massachusetts to Texas during the period extending from 1980 to 1998. Fibropapillomatosis (FP) was reported only on green turtles in the southern half of Florida (south of 29 degrees N latitude). Within this region, 22.6% (682/3,016) of the turtles had tumors. Fibropapillomatosis was more prevalent in turtles found along the western (Gulf) coast of Florida (51.9%) than in turtles found along the eastern (Atlantic) coast of Florida (11.9%) and was more prevalent in turtles found in inshore areas (38.9%) than in turtles found in offshore areas (14.6%). A high prevalence of FP corresponded to coastal waters characterized by habitat degradation and pollution, a large extent of shallow-water area, and low wave energy, supporting speculation that one or more of these factors could serve as an environmental cofactor in the expression of FP. A high prevalence of FP did not correspond to high-density green turtle assemblages. Turtles with tumors were found most commonly during the fall and winter months, and the occurrence of tumors was most common in turtles of intermediate size (40-70-cm curved carapace length). Stranded green turtles with tumors were more likely to be emaciated or entangled in fishing line and less likely to have propeller wounds than were stranded green turtles without tumors. Turtles with and without tumors were equally likely to show evidence of a shark attack. The percent occurrence of tumors in stranded green turtles increased from approximately 10% in the early 1980s to over 30% in the late 1990s. Fibropapillomatosis was first documented in southernmost Florida in the late 1930s and spread throughout the southern half of Florida and the Caribbean during the mid-1980s. Because green turtles living in south Florida are known to move throughout much of the Caribbean, but are not known to move to other parts of the USA or to Bermuda, the spread and current distribution of FP in the western Atlantic, Gulf of Mexico, and Caribbean can be explained by assuming FP is caused by an infectious agent that first appeared in southern Florida. Aberrant movements of captive-reared turtles or of turtles that are released into areas where they were not originally found could spread FP beyond its current distribution.     

Skull shape variation in extant and extinct Testudinata and its relation to habitat and feeding ecology

Turtles (Testudinata) are a diverse group of reptiles that conquered a broad set of habitats and feeding ecologies over the course of their well‐documented evolutionary history. We here investigate the cranial shape of 171 representatives of the turtle lineage and the relationship of shape to different habitat and diet preferences using two‐dimensional geometric morphometrics. The skull shape of extant turtles correlates with both ecological proxies, but is more affected by habitat than diet. However, the application of these correlations to extinct turtles produces mostly flawed results, as least when compared to external data such as sedimentary environment, highlighting that the morphospace held by extant turtles is not necessarily the optimal location in tree space for a particular ecology. The inability of this study to correctly predict the ecology of extinct turtles is likely related to the fact that the shape of turtle skulls is dominated by the emarginations and jaw closure mechanisms, two shape features unrelated to habitat or feeding ecology. This indicates that various specializations that are apparent in the skull only contribute little to overall shape.     

Road avoidance and its energetic consequences for reptiles

Roads are one of the most widespread human‐caused habitat modifications that can increase wildlife mortality rates and alter behavior. Roads can act as barriers with variable permeability to movement and can increase distances wildlife travel to access habitats. Movement is energetically costly, and avoidance of roads could therefore impact an animal's energy budget. We tested whether reptiles avoid roads or road crossings and explored whether the energetic consequences of road avoidance decreased individual fitness. Using telemetry data from Blanding's turtles (Emydoidea blandingii; 11,658 locations of 286 turtles from 15 sites) and eastern massasaugas (Sistrurus catenatus; 1,868 locations of 49 snakes from 3 sites), we compared frequency of observed road crossings and use of road‐adjacent habitat by reptiles to expected frequencies based on simulated correlated random walks. Turtles and snakes did not avoid habitats near roads, but both species avoided road crossings. Compared with simulations, turtles made fewer crossings of paved roads with low speed limits and more crossings of paved roads with high speed limits. Snakes made fewer crossings of all road types than expected based on simulated paths. Turtles traveled longer daily distances when their home range contained roads, but the predicted energetic cost was negligible: substantially less than the cost of producing one egg. Snakes with roads in their home range did not travel further per day than snakes without roads in their home range. We found that turtles and snakes avoided crossing roads, but road avoidance is unlikely to impact fitness through energetic expenditures. Therefore, mortality from vehicle strikes remains the most significant impact of roads on reptile populations.     

New taxa described in Zoology in the Middle East

Abstract

The region between Mersin and ?skenderun was selected for studying marine turtles in the Turkish waters of the Mediterranean sea, as the most important nesting grounds of Green Turtles (Chelonia mydas) in the Mediterranean are situated there. In the 1995–96 fishing season, the 5 trawl boats taking part in the project reported that nets in the Eastern Mediterranean trapped 160 Green Turtles and 26 Loggerhead Turtles (Caretta caretta). In the following trawling season (1996/97), 306 Green Turtles, 116 Loggerhead Turtles (Caretta caretta) and 437 Nile Soft-shelled Turtles (Trionyx triunguis) were found to be trapped as a by-catch in the trawling nets. 87% of these turtles were captured by mid-trawling nets, the rest by bottom-trawling nets, mostly at depths of 11–30 m. 95% of all turtles were caught alive and healthy, and were usually released back into the sea immediately after capture by the fishermen. Training measures were given to local fishermen in order to raise their awareness of the threats to marine turtles.     

Oxidative stress indicators and chemical contaminants in East Pacific green turtles (Chelonia mydas) inhabiting two foraging coastal lagoons in the Baja California peninsula

In order to determine the potential effects of contaminants in juveniles of East Pacific green turtle, Chelonia mydas, captured alive, circulating trace metal and organochlorine pesticide concentrations were correlated with body condition, antioxidant enzyme activities and lipid peroxidation levels. Turtles were sampled in Punta Abreojos (PAO) and Bahía Magdalena (BMA). Turtles from PAO showed higher silicon and cadmium concentrations, but lower α-hexachlorocyclohexane, γ-hexachlorocyclohexane, hexachlorobenzene and aldrin concentrations than individuals from BMA. In BMA cadmium concentration decreased as the standard carapace length of the turtles increased. In PAO concentrations of α-hexachlorocyclohexane, heptachlor and hexachlorobenzene were positively correlated with the weight of the individuals. Lipid peroxidation levels were positively correlated with cadmium concentrations. In turtles captured in PAO, enzymatic antioxidant activities correlated mostly with pesticide concentrations, while in individuals from BMA enzyme activities were correlated with trace element concentrations. Correlations between antioxidant enzyme activities and concentration of xenobiotics suggest physiological sensitivity of East Pacific green turtles to chemicals. Regional differences found could be influenced by habitat conditions such as currents, upwellings (PAO) and agricultural activities (BMA). We suggest that, combined, circulating contaminant concentrations, lipid peroxidation levels and antioxidant enzyme activities in sea turtles could be used as biomarkers of the habitat conditions.     

Variation in life-history characteristics among populations of North American wood turtles: a view from the north

Life-history traits such as age at maturity, body size and clutch size tend to vary across a species' distribution. The purpose of our study was to describe the demography of a newly discovered population of North American wood turtles Glyptemys insculpta at the species' northern range limit, and to compare our findings to those of other studies to test hypotheses about adaptive life-history variation. Turtles were hand-captured from May to October 2005 and 2006 along a 4.5 km stretch of river located in the Sudbury District, ON, Canada (46°N). Fifty-five captured individuals provided a population density estimate of 1.3 turtles/100 m of river. Juveniles comprised 35% of wood turtles captured, and growth ring counts (i.e. age estimates) indicated recruitment in each of the past 11 years. Among populations, we found a nonlinear pattern in body size variation with the largest turtles in the north, smallest turtles in the centre of the range, and intermediate-sized turtles in the south. This nonlinear pattern in body size was reflected in clutch size variation. Selective pressures to overcome years of low recruitment may have resulted in larger body sizes and hence large clutch sizes at northern latitudes while conspecifics at southern latitudes can achieve larger body sizes because they live in a more productive environment. Population density decreased with latitude, likely as a result of a gradient in habitat productivity.     

Modifications of traps to reduce bycatch of freshwater turtles

Mortality of freshwater turtles varies among types and deployments of traps. There are few or no losses in hoop or fyke traps set where turtles may reach air, including placement in shallows, addition of floats on traps, and tying traps securely to a stake or to shore. Turtle mortality occurs when traps are set deep, traps are checked at intervals >1 day, and when turtles are captured as bycatch. Devices are available that exclude turtles from traps set for crab or game fish harvest. Slotted gates in front of the trap mouth reduce turtle entry, but small individuals still may be trapped. Incidental take of turtles is preventable by integrating several designs into aquatic traps, such as adding floats to the top of traps so turtles may reach air or an extension tube (chimney, ramp) that creates an escape route. © 2010 The Wildlife Society.     

Hematologic and serum biochemical values of gravid freshwater Australian Chelonians

Hematologic and serum biochemical analyses were performed on 30 wild-caught, gravid, Australian freshwater chelonians. Species sampled were western long-necked turtles (Chelodina oblonga; n = 13), common long-necked turtles (Chelodina longicollis; n = 8), and Murray River turtles (Emydura macquarii; n = 9). Turtles were obtained from Lake Goolellal in Perth, Western Australia (C. oblonga), and Lake Coranderrk in Healesville, Victoria (C. longicollis and E. macquarii). All turtles were considered healthy at the time of sample collection. Blood results were similar to those reported in other freshwater chelonians, with the exception of elevated calcium levels in all species. Hypercalcemia was attributed to egg development and maturation. A hemoparasite morphologically resembling Haemogregarina clelandi was found in all C. oblonga samples and in four C. longicollis samples. Infection with H. clelandi appeared to have no physiological effects on blood parameters or morphometrics of infected turtles. Blood parameters were also considered poor indicators of female chelonian morphometrics and fecundity.     

不同生境间龟鳖类体型的差异

体型是动物重要的形态特征,影响动物的生境利用。为揭示龟鳖类体型与生境之间的关系,通过文献收集331种龟鳖(龟鳖目Tesudines总物种数的98.8%)的最大背甲长及其生境信息,将生境分为海洋、淡水、岛屿性陆地和大陆性陆地4种类型,再将淡水生境分为大静水、大流水、小静水、小流水和所有水域5种亚类型,大陆性陆地生境分为高地、平地和荒漠3种亚类型,从而比较不同生境类型或亚类型之间龟鳖类体型的差异。广义线性混合模型分析结果显示:1)海龟体型最大,岛屿性陆龟次之,淡水龟鳖和大陆性陆龟体型最小,且后两者差异无统计学意义。2)淡水龟鳖类的体型在5种亚类型生境间存在差异,大静水和大流水水域的体型均显著大于小静水和小流水水域,而体型在大静水与大流水水域、小静水与小流水水域之间的差异均无统计学意义,表明淡水龟鳖类体型与水域面积有关,而与水域是静水或流水无关。广布所有水域的淡水龟鳖类体型趋于中间型,且与其他4种亚类型生境中的体型之间的差异均无统计学意义。3)大陆性陆龟的体型从高地到平地再到荒漠有逐渐变大的趋势,但差异无统计学意义。本研究揭示龟鳖类的保护对策需要考虑其体型和生境面积的相关性。     

Demographic and tumour prevalence data for juvenile green turtles at the Coastal-Marine Protected Area of Cerro Verde,Uruguay

Marine Protected Areas are increasingly considered in coastal areas as an instrument to preserve threatened fauna and fragile habitats from the detrimental effects of human activities. For this reason baseline data are of utmost importance for the evaluation of the outcomes of ongoing conservation efforts. Along the Uruguayan coast, the area of Cerro Verde (declared protected since 2011) represents the most important foraging and development area for green turtles (Chelonia mydas). Between 2002 and 2009, a long-term capture-mark-recapture programme for green turtles was developed to gather data on demography, ecology and status of the species in the area. Turtles captured were juveniles ranging from 28.8 to 64.3?cm in length over the curve of the carapace (n?=?514), and results indicated a size-based habitat segregation. Tumour prevalence was 5.3% (n?=?27) and was positively correlated with carapace length. The mean body condition index was 1.25?±?0.14 (n?=?494). From the total number of tagged turtles 10.6% were recaptured during the study period. Green turtles showed high site fidelity; 81% of the turtles were recaptured within the same season and 76% were recaptured in different seasons but were found at the original capture spot. Mean annual growth rate was 1.6?±?0.9?cm year^?1. The catch per unit effort of 2008 differed from 2009, higher in 2009, but also significantly different between capture spots. The present study constitutes a baseline dataset for future monitoring of green turtles in the area and provides valuable information for wider analyses of population dynamics in the Southwestern Atlantic Ocean.     

Thermoregulation of spotted turtles (Clemmys guttata) in a beaver-flooded bog in southern Ontario,Canada

Body temperature has a major influence on the physiological processes, growth, reproductive output, and overall survival of ectotherms. When a habitat is altered as a result of natural or anthropogenic influences, the available temperatures in the habitat can change, thus affecting an animal's ability to thermoregulate. We studied thermoregulation in response to habitat change in a population of spotted turtles (Clemmys guttata) in Southern Ontario, Canada. Historically, the study site was ditched to draw down water levels to facilitate peat mining, and the resulting drainage ditches were the only habitat containing surface water and turtles were restricted to these drains. Recent colonization of the site by beaver (Castor canadensis) caused increases in water level and water surface area. We followed spotted turtles (N=16) outfitted with radio transmitters and iButtons to estimate body temperatures (T_b) continuously throughout the active season post-flooding. Turtle models outfitted with iButtons (N=50) were deployed in the nine available habitat types to record environmental temperatures (T_e). Turtles (N=13) were tested in a thermal gradient under laboratory conditions to determine preferred body temperature range (T_set). The T_set for the population ranged from 20 °C to 26 °C. In the field, T_b was within the T_set range 28% of the time from March to October, and 67% of the time from July to August. Efficiency of thermoregulation was calculated to be highest in July and August. The habitat type with the highest thermal quality was the shallow flooded zone created by beaver damming, and the habitat with the lowest thermal quality was the drain bottom, the drains being the only aquatic habitat available prior to flooding. This study confirms that beaver flooding provided a wide variety of preferable thermal opportunities for spotted turtles. Further investigation is needed to determine the effects of flooding on spotted turtle thermoregulation during nesting and hibernation.     

Hemoglobins of reptiles. The primary structure of the major and minor hemoglobin component of adult Western Painted Turtle (Chrysemys picta bellii)

Red blood cells of adult Western Painted Turtles (Chrysemys picta bellii) contain two hemoglobin components: HbA (alpha A2 beta 2) and HbD (alpha D2 beta 2). We present the complete amino-acid sequences of the alpha A-chains from the major component and of the beta-chains common to both components. Structural features are discussed with respect to the animals extreme tolerance of severe hypoxic conditions during hibernation which is accompanied by a high oxygen affinity of the hemoglobin. The strong ATP dependence of Western Painted Turtle hemoglobin oxygen affinity is contrasted by the loss of one ATP-binding site, beta 143(H21)-Arg----Leu. The primary structure of the beta-chains excludes an allosteric control mechanism by hydrogencarbonate as it was found in crocodiles. Except in turtles a hemoglobin pattern with HbA and HbD sharing the same beta-subunits has been found only in birds. In comparison to other vertebrate hemoglobins there is a surprising similarity of the sequences to those of bird hemoglobins. alpha A- as well as alpha D-chains show larger homologies to chains of the same type in different species than alpha A- and alpha D-chains to each other in the same species. This indicates a duplication of the alpha-gene preceding the divergence of turtles and birds.     

Post-nesting migrations patterns of Green Turtles (Chelonia mydas) from the Egyptian Red Sea

In order to identify the migratory pathways and foraging grounds of post-nesting Green Turtles (Chelonia mydas) in the Red Sea, we attached satellite transmitters to four females immediately after egg deposition and tracked them between 207 and 647 days. We identified four geographically distinct post-nesting habitat areas and migration paths from Zabargad Island, Egypt which was remarkable given our small sample size. Our shortest migration was 140?km and the longest 940?km, with the migrations and post-nesting habitat encompassing the boundaries of four of the seven Red Sea countries (Egypt, Sudan, Eritrea, and Saudi Arabia). The post-nesting habitats were located in shallow coastal habitat and three consisted of near-shore archipelagos. Two turtles moved past areas of suitable post-nesting habitat that was occupied by other turtles, which suggests that these turtles may be exhibiting fidelity to certain feeding and nesting sites. Our results suggest that regional and multi-national cooperation will be needed to protect sea turtles that nest on Zabargad Island, a nesting site that is important for Egypt and other Red Sea nations.     

Retrospective pathology survey of green turtles Chelonia mydas with fibropapillomatosis in the Hawaiian Islands, 1993--2003

We necropsied 255 stranded green turtles Chelonia mydas with fibropapillomatosis (FP) from the Hawaiian Islands, North Pacific, from August 1993 through May 2003. Of these, 214 (84 %) were euthanized due to advanced FP and the remainder were found dead in fresh condition. Turtles were assigned a standardized tumor severity score ranging from 1 (lightly tumored) to 3 (heavily tumored). Tumors were counted and measured and categorized as external, oral, or internal and tissues evaluated by light microscopy. Turtles in tumor score 2 and 3 categories predominated, and tumor score 3 turtles were significantly larger than the other 2 categories. More juveniles stranded than subadults or adults. Total cross-sectional area of tumors increased significantly with straight carapace length (SCL). Frequency distribution of total number of external tumors per turtle was significantly skewed to the right, and there were significantly more tumors at the front than rear of turtles. Eighty percent of turtles had oral tumors, and 51% of turtles with oral tumors had tumors in the glottis. Thirty-nine percent of turtles had internal tumors, most of them in the lung, kidney and heart. Fibromas predominated in lung, kidney and musculoskeletal system whereas myxofibromas were more common in intestines and spleen. Fibrosarcomas of low-grade malignancy were most frequent in the heart, and heart tumors had a predilection for the right atrium. Turtles with FP had significant additional complications including inflammation with vascular flukes, bacterial infections, poor body condition, and necrosis of salt gland. Turtles with oral tumors were more likely to have secondary complications such as pneumonia. Most turtles came from the island of Oahu (74%) followed by Maui (20 %), Hawaii, Molokai, and Lanai (<3 % each). On Oahu, significantly more turtles we necropsied stranded along the northwestern and northeastern shores.     

Structure and variation of the Nucleolus Organizer Region in turtles

Differential staining techniques were used to study the structure and variation of the NORs of 27 species of cryptodiran turtles. No species or individuals had more than a single pair of NORs. Extensive variation in NOR structure and chromosomal location was found among higher taxa and individual variation in NOR size was common. Thirty eight percent of all individuals studied were heterozygous for the size of the NOR. However, interspecific variation in chromosomal location and structure of the NOR within major taxa was relatively rare. It is concluded that ( I ) the pattern of variation of NORs is consistent with patterns of chromosomal evolution in turtles; (2) Turtles have only a single pair of NORs whereas other animals, such as some mammals, possess numerous NORs; (3) The heterochromatin associated with the NOR is involved in the structure of the nucleolus.     

Temperature effects on snapping performance in the common snapper Chelydra serpentina (Reptilia, Testudines)

Studies on the effect of temperature on whole-animal performance traits other than locomotion are rare. Here we investigate the effects of temperature on the performance of the turtle feeding apparatus in a defensive context. We measured bite force and the kinematics of snapping in the Common Snapping Turtle (Chelydra serpentina) over a wide range of body temperatures. Bite force performance was thermally insensitive over the broad range of temperatures typically experienced by these turtles in nature. In contrast, neck extension (velocity, acceleration, and deceleration) and jaw movements (velocity, acceleration, and deceleration) showed clear temperature dependence with peak acceleration and deceleration capacity increasing with increasing temperatures. Our results regarding the temperature dependence of defensive behavior are reflected by the ecology and overall behavior of this species. These data illustrate the necessity for carefully controlling T(b) when carrying out behavioral and functional studies on turtles as temperature affects the velocity, acceleration, and deceleration of jaw and neck extension movements. More generally, these data add to the limited but increasing number of studies showing that temperature may have important effects on feeding and defensive performance in ectotherms.     

Responses of an Australian freshwater turtle to drought‐flood cycles along a natural to urban gradient

Urban areas provide habitat for numerous native species, but life in towns and cities presents many challenges. The effect of climate on the ecology and the behaviour of non‐volant vertebrates inhabiting urban habitats have received little attention. In this study, we investigated demography, growth rates, movements and reproduction of a semi‐aquatic freshwater turtle, Chelodina longicollis, along a natural to urban gradient during a period of relatively high rainfall (2011–2014) and compared this to a previous study in the same system during drought (2006–2007). In addition to changes in rainfall, urbanization increased considerably over the same time period and a pest‐exclusion fence was constructed to mitigate against urban hazards encroaching on the adjacent reserve. Turtles grew at similar rates, had similar abundances and sex ratios and had similar reproductive output across the gradient from urban to non‐urban sites during the wet period. Despite increasing urbanization, recruitment occurred at all sites and survivorship estimates were similar among sites. Turtles moved among wetlands at high rates and over long distances (6 km), underscoring the importance of movements in urban landscapes. Our results contrast with those for the same system during drought, when turtles were less abundant and grew slower in the nature reserve compared with the urban environment. Our results underscore the strong influence climate can have on population dynamics and resilience of species to changes brought about by urbanization. Further monitoring is required to understand the long‐term population responses of long‐lived species to drought cycles.