气候变化条件下太平洋丽龟的适宜生境及其变化

太平洋丽龟作为被国际自然保护联盟(IUCN)认定的脆弱物种,近年来备受关注。为了解当前及未来气候情景条件下太平洋丽龟的分布及其变化,本研究利用其发现记录和8个环境预测变量(包括深度、离岸距离、平均初级生产力、最小初级生产力、海表平均温度、海表最小温度、海表平均盐度、海表最小盐度),构建了组合物种分布模型(Ensemble SDM)对其潜在栖息地分布进行预测,并利用曲线下面积(AUC)和真实技巧统计(TSS)值评估模型的准确性。结果表明：AUC和TSS值分别为0.96和0.81,表明组合模型具有较好的预测性能;海洋表面温度和盐度是决定太平洋丽龟分布最重要的两个预测变量,适宜温度为23～29℃,适宜盐度<34;当前环境条件下太平洋丽龟分布范围在30°N—25°S;在未来气候情景条件下,该物种的分布范围将减少,特别是在2100s RCP85气候情境下,其适宜生存范围将减少28%。模型验证结果显示,模型准确性较高,能对太平洋丽龟在当前和未来气候情景下的分布做出较为准确的预测。本研究可为制定更加合理的保护措施和管理策略提供数据参考。     

海龟漫谈

海龟是对生活在海洋里的各种龟类的总称，它们广泛地分布于全球各地温暖的海域里。全世界现存的海龟共有7种，我国有5种，分别是：海龟（也叫绿海龟），蠵（xi）龟、玳瑁、丽龟（也叫太平洋丽龟）和棱皮龟。     

棱皮龟的大体解剖

对1例渔民误捕死亡的棱皮龟循环系统、消化系统、呼吸系统和泌尿生殖系统进行了解剖观察。主要特点有：心脏位于胸部正中位置;食管内壁有许多锥状突起,可能起过滤、辅助吞咽食物的作用;肠长360．0cm,占整个消化管长度的51．9％;卵巢形似鸡冠花花瓣,大约有4～6万个未成熟卵细胞,推测为一少年龟。     

蒙原羚亚成体外部形态及消化道若干指标的测量分析

对在内蒙古自治区新巴尔虎右旗猎捕到的蒙原羚(Procapragutturosa)亚成体的外部形态及消化道若干指标进行了测量及分析,结果表明,蒙原羚亚成体的体重平均为27.47kg,体长平均为105.37cm,尾长平均为10.94cm,肩高平均为56.55cm。蒙原羚亚成体胃(含胃容物)的总重为5.26kg,占体重的19.15%;瘤胃(含胃容物)重(平均3.81kg)占胃总重的72.43%;肠道总长为2708.86cm,是体长的25·71倍;小肠总长为1909.87cm,占肠道总长的70.50%;大肠总长为798.99cm,占肠道总长的29.50%。蒙原羚亚成体兼有精饲者和粗饲者的特征。     

黄喉拟水龟的繁殖生物学研究

1998年4-11月对黄喉拟水龟的繁殖生物学进行了研究,在广东,黄喉拟水龟的产卵高峰期在5-6月,窝卵量1-7枚,平均2.5枚;卵重平均13.95g;长径平均4.34cm;短径平均2.23cm。卵重与卵长径呈正相关关系,在25-32℃、沙床含水量5-10%孵化条件下,孵化时间平衡73.8d,孵化率84.2%。初生稚龟均重9.75g。背甲长平均3.77cm;背甲宽平均2.91cm。稚龟体重与背甲长、宽呈极显著的正相关关系,稚龟经8-11月3个月生长,平均日增重0.149g。稚龟体重、背甲长、宽与日龄呈极显著的正相关关系。稚龟体重与背甲长宽也呈极显著的正相关关系。     

深澳湾太平洋牡蛎养殖容量研究

文章采用方建光模型,通过对广东省南澳县深澳湾养殖环境的水温、叶绿素a、初级生产力和非养殖滤食性动物生物量的调查,结合室内测定的不同规格壳长的太平洋牡蛎(Crassostrea gigas)的滤水率,并参照非养殖滤食性动物相应的滤水率,对深澳湾各月份不同规格太平洋牡蛎养殖容量进行估算。研究发现,深澳湾各规格的太平洋牡蛎最大养殖容量出现在1月份和2月份,最小养殖容量出现在5月份。各规格的太平洋牡蛎年平均养殖容量分别为:壳长3.5～5.0 cm的太平洋牡蛎年平均养殖容量为27 ind/m²,壳长5.5～7.0 cm的太平洋牡蛎年平均养殖容量为16 ind/m²,壳长7.5～9.0 cm的太平洋牡蛎年平均养殖容量为17 ind/m²,壳长9.5～11.0 cm的太平洋牡蛎年平均养殖容量为16 ind/m²。     

雕鸮消化系统形态学的初步研究

对一只雕消化系统的形态学作了初步的观察与研究,结果表明:雕舌呈鞋底形,舌根分叉,叉粘膜上具有尖端指向后方的栉状突;食管宽而扁,无明显可见的嗉囊;肌胃无明显的类角质膜;肠道长是体长的2.05倍,小肠较发达,长970.5 mm,占肠道总长的75.7%,具有较发达的双侧盲肠。并与蛇雕、毛脚、黑鸢的消化系统进行了比较。     

齿缘摄龟线粒体基因组全序列与系统进化

采用常规PCR扩增并测序获得了齿缘摄龟(Cyclemys dentata)线粒体DNA(mtDNA)全序列,并研究了其基因组结构特点;根据20种龟的线粒体基因组重链蛋白编码基因序列,分别利用最大简约法(MP)、最大似然法(ML)和贝叶斯法(Bayesian)构建系统进化树,探讨这些龟鳖物种之间的系统进化关系。结果显示,齿缘摄龟线粒体基因组全序列长为16489 bp(GenBank登录号为JX455823),A+T含量为61.51%,编码37个基因,包括13个蛋白质编码基因,2个rRNA,22个tRNA和1个控制区(Dloop),基因组成与其他龟鳖类动物相似;非编码区D-loop长973 bp,包含1个中央保守区(CD),2个扩展终止结合序列区(ETASs),3个保守盒(CSBs);构建的MP树、ML树和Bayesian树的拓扑结构相似,闭壳龟属7种龟聚为一枝,拟水龟属6种龟聚为一枝,齿缘摄龟与黑桥摄龟聚在一枝,3种进化树均支持这些龟鳖物种现有的分类学地位。     

灰胸薮鹛消化系统形态的初步研究

对灰胸薮鹛（Liocichla omeiensis）消化系统的形态学作了初步观察,结果表明,灰胸薮鹛舌前端有刺毛状结构,后端有一排尖端后指的栉状突,且中间小两边大;雄鸟在舌前端正中央还有一“v”形的凹缺,深约2．5mm;雌鸟食道颈段长为13．2mm,雄鸟为17．5mm;嗉囊雌鸟长7．5mm,雄鸟长8．4mm;食道胸段雌鸟长15．5mm,雄鸟长14．7mm;肌胃发达,具角质膜,腺胃乳突短而小;肠道长与体长基本相等,小肠较发达,雌鸟长153．7mm,占肠道总长92．6％,雄鸟为133mm和95％,具有双侧盲肠,占肠道总长的3．3％,大肠短,雌鸟仅占肠道7．5％,雄鸟仅占4．75％;肝为体内最大的消化腺,分左右两叶;胰位于十二指肠袢内,细长形,分三小叶。     

Development and characterization of novel microsatellite markers from the olive ridley sea turtle (Lepidochelys olivacea)

Olive ridley turtles, although widely distributed globally and in Indian coastal waters, have undergone declines in recent years due to anthropogenic factors, particularly fishery‐related mortality. Assessment of genetic variability in existing populations is critical to the development of effective conservation strategies. Here we describe the development of six highly polymorphic microsatellite loci from a simple sequence repeat‐enriched genomic DNA library of olive ridley turtle. Characterization of five of these loci using 83 individual olive ridley turtles revealed eight to 24 alleles per locus, high observed and expected heterozygosity values and broad cross‐species amplifications. The sixth microsatellite was found to be monomorphic in the olive ridley samples but was polymorphic in two related marine turtle species. These microsatellites thus provide efficient genetic markers to understand the population structure, phylogeography and species relationships of olive ridley and other marine turtle species.     

A first estimate of sea turtle bycatch in the industrial trawling fishery of Gabon

Gabon hosts nesting grounds for several sea turtle species, including the world’s largest rookery for the leatherback turtle (Dermochelys coriacea), Africa’s largest rookery for the olive ridley turtle (Lepidochelys olivacea) and smaller aggregations of the hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas). To assess the level of incidental captures of turtles by the Gabonese trawl fishery, an onboard observer program was conducted in the period 2012–2013. A total of 143 turtles were captured by 15 trawlers during 271 fishing days. The olive ridley turtle was the main species captured (80% of bycaught turtles), with mostly adult-sized individuals. The remaining 20% included green turtles, hawksbill turtles, leatherback turtles and undetermined species. Bycatch per unit of effort (BPUE) of olive ridley turtles varied greatly depending on the period of the year (range of means: 0.261–2.270). Dead and comatose turtles were 6.2 and 24.6% respectively (n = 65). By applying the available fishing effort to two BPUE scenarios (excluding or considering a seasonal peak), the total annual number of captures was estimated as ranging between 1026 (CI 95% 746–1343) and 2581 (CI 95% 1641–3788) olive ridley turtles, with a mortality ranging from 63 (CI 95% 13–135) to 794 (CI 95% 415–1282) turtles per year depending on the scenario and on the fate of comatose turtles. Such a potential mortality may be reason for concern for the local breeding population of olive ridley turtles and recommendations in terms of possible conservation measures and further research are given.     

Mass nesting of sea turtles along the east coast of India: A sustainable environmental management approach

We analyzed the marine environmental setting to characterize the mass nesting habitat of Olive ridley sea turtles from three locations of the river mouth region i.e., Gahirmatha, Devi, and Rushikulya along the coast, of the Bay of Bengal. The environmental variables such as sea surface temperature (SST), ocean current, mixed layer depth, and chlorophyll-a (Chl-a) were analyzed to examine its influence on the mass nesting of sea turtles. The clear pattern of the mass population shows the nearshore and river mouth region of the nesting site throughout the inter-nesting range. The population was dense at the river mouth of Gahirmatha followed by Devi and Rushikulya. We found a significant linear relationship between the Chl-a and nesting population (r = 0.98, p ≤ 0.0001); and the SST and nesting population (r = 0.78, p ≤ 0.0001) at all river mouths. The conducive environmental threshold limit of SST and Chl-a was ≤29 0C and ≤ 0.5 mg m-3 respectively. The mass nesting, breeding, and migration of Olive ridley are attributed to the geomorphologic basin structure, physicochemical parameters, and feeding potential grounds in the coastal water. Inter nesting of movements in relation to the influential environment variables, the present and proposed regions for Olive ridley need to be implemented to provide comprehensive protection to both nesting populations and locations. The present study provides new knowledge on the linkage between the marine ecosystem and the mass nesting habitat of the sea turtle population for long-term monitoring, conservation application, and sustainable ecosystem management.     

Use of restriction fragment length polymorphisms to identify sea turtle eggs and cooked meats to species

One of the many threats to sea turtlepopulations is the take of turtles and theireggs for consumption and sale. Improved speciesidentification methods for sea turtle eggs andcooked meats would facilitate prosecution ofthose involved. Fatty acid-based methods toidentify eggs cannot resolve loggerheads andthe two ridley species. Protein-based methodsare not applicable to eggs or cooked meat. Wepresent methods to extract DNA from turtle eggand cooked meat and to produce diagnosticrestriction fragment length polymorphismpatterns in the cytochrome b region of themitochondrial DNA. This method works on DNAfrom any tissue, and provides wildlife lawenforcement another tool to combat illegal takeof endangered species.     

Development and characterization of ten novel microsatellite markers from olive ridley sea turtle (Lepidochelys olivacea)

Olive ridleys, one of the widely distributed marine turtle species has undergone declines in recent years due to multiple anthropogenic factors warranting conservation efforts for which assessment of genetic variability in existing populations become critical. Here we describe development of ten new microsatellite markers from a short sequence repeat-enriched partial genomic DNA library, which are found to be highly informative for genetic studies. Eight of these markers when tested on 83 olive ridley turtles revealed high allelic diversity (4–27 alleles per marker), and high observed and expected heterozygosity estimates that ranged from 0.29 to 0.82 and 0.62 to 0.94, respectively. Two microsatellites were monomorphic in the tested olive ridley samples, but were found to be informative/polymorphic when tested on related marine turtle species. More importantly, nine of the new markers showed robust cross-species amplifications in three related species Dermochelys coriacea, Chelonia mydas and Eretmochelys imbricata. Thus, this study describes ten new microsatellite markers and also demonstrates their potential as efficient genetic markers in studies related to parentage analysis, population structure, phylogeography and species relationships of olive ridleys and other marine turtle species.     

鼋骨骼系统及与中华鳖比较

采用虫蚀法制备了鼋Pelochelys cantorii和中华鳖Pelodiscus sinensis的骨骼标本, 对骨骼系统进行了观察、描述、绘图及比较分析。结果显示, 鼋的骨骼共169枚, 由背甲和腹甲组成的外骨骼、中轴骨和附肢骨组成的内骨骼组成。通过比较鼋和中华鳖的骨骼结构, 发现二者在头骨的吻突长度及第三颈椎结构方面有较大差别。鼋眼眶前部至吻突最前端的长度与头骨总长度比为0.082, 而中华鳖为0.570, 显示中华鳖吻突显著长于鼋。鼋与中华鳖的颈椎骨数目均为9枚, 但中华鳖的第三至第九颈椎的横突要更明显, 第七颈椎的椎体向上显著翘起, 且第九颈椎腹面椎体前端为尖状。从整条颈椎上看, 鼋脊椎长度与其背甲长度之比为0.66, 中华鳖为1.07, 表明中华鳖的颈椎更长; 研究结果丰富了鳖科动物的骨骼学基础数据, 也为鼋物种鉴定、龟鳖动物系统演化及生态适应性提供骨骼学理论依据。     

Bioko: critically important nesting habitat for sea turtles of West Africa

We evaluate the conservation status and threats faced by sea turtle nesting populations at Bioko Island, Equatorial Guinea (Central Africa). Beaches were monitored to obtain a detailed sea turtle nest census and, where possible, tagging of adult females was undertaken. Four sea turtle species were found nesting in the area: the green turtle (Chelonia mydas), the leatherback (Dermochelys coriacea), the olive ridley (Lepidochelys olivacea) and the hawksbill (Eretmochelys imbricata); with the former two species nesting in regionally important numbers. Nesting activity was concentrated between November and February, with a peak in December–January. Tagging and recapture of green turtles in two consecutive seasons suggested an estimated 560 (interquartile range: 420–1,681) and 414 (interquartile range: 190–1,255) nesting females in the area, respectively. Estimated numbers of nesting leatherbacks ranged from 123 to 215 and 243 to 293 in the first and second season, respectively. The other two species were less abundant (olive ridley: 19–29 and 28–43; hawksbill: 4–10 and 2 turtles). Data were compared with more recent surveys in the area and contextualised with information on human related threats. Despite the size of nesting stocks, ongoing permitted and illegal take of adult turtles at the nesting site constitutes a serious threat for these breeding aggregations. Additionally, tag returns from throughout the Gulf of Guinea suggest that the level of take in regional fisheries may also be a major threat.     

Risk analysis reveals global hotspots for marine debris ingestion by sea turtles

Plastic marine debris pollution is rapidly becoming one of the critical environmental concerns facing wildlife in the 21st century. Here we present a risk analysis for plastic ingestion by sea turtles on a global scale. We combined global marine plastic distributions based on ocean drifter data with sea turtle habitat maps to predict exposure levels to plastic pollution. Empirical data from necropsies of deceased animals were then utilised to assess the consequence of exposure to plastics. We modelled the risk (probability of debris ingestion) by incorporating exposure to debris and consequence of exposure, and included life history stage, species of sea turtle and date of stranding observation as possible additional explanatory factors. Life history stage is the best predictor of debris ingestion, but the best‐fit model also incorporates encounter rates within a limited distance from stranding location, marine debris predictions specific to the date of the stranding study and turtle species. There is no difference in ingestion rates between stranded turtles vs. those caught as bycatch from fishing activity, suggesting that stranded animals are not a biased representation of debris ingestion rates in the background population. Oceanic life‐stage sea turtles are at the highest risk of debris ingestion, and olive ridley turtles are the most at‐risk species. The regions of highest risk to global sea turtle populations are off of the east coasts of the USA, Australia and South Africa; the east Indian Ocean, and Southeast Asia. Model results can be used to predict the number of sea turtles globally at risk of debris ingestion. Based on currently available data, initial calculations indicate that up to 52% of sea turtles may have ingested debris.     

Fishhook lesions in loggerhead sea turtles

This study describes four cases of loggerhead sea turtles with fishhooks in the gastrointestinal tract. Two dead turtles with a hook in the esophagus had local fibrosis with an invagination of the keratinized stratified squamous epithelium surrounding the hook, isolating it from the subjacent stroma, one had a hook in the cloaca which was expelled spontaneously, and one had plication of the intestine with necrosis caused by the long monofilament line attached to the hook lodged in the esophagus. Lethal injuries were related to the effect of strangulation and traction produced by the line throughout the gastrointestinal tract rather than the presence of the hook in the esophageal mucosa. Hook size, point of attachment to the gastrointestinal tract, the presence or not of a long monofilament line, and the traction applied by it could be crucial for turtle survival.     

Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas

Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the Jurassic period. Sea turtles are often exposed to rapidly altered environmental conditions during diving periods. This may reduce their blood pH during prolonged hypoxic dives. This report demonstrates that five species of turtles possess only one branch of the mammalian coagulation pathway, the extrinsic pathway. Mixing studies of turtle plasmas with human factor-deficient plasmas indicate that the intrinsic pathway factors VIII and IX are present in turtle plasma. These two factors may play a significant role in supporting the extrinsic pathway by feedback loops. The intrinsic factors, XI and XII are not detected which would account for the inability of reagents to induce coagulation via the intrinsic pathway in vitro. The analysis of two turtle factors, factor II (prothrombin) and factor X, demonstrates that they are antigenically/functionally similar to the corresponding human factors. The turtle coagulation pathway responds differentially to both pH and temperature relative to each turtle species and relative to human samples. The coagulation time (prothrombin time) increases as the temperature decreases between 37 and 15 °C. The increased time follows a linear relationship, with similar slopes for loggerhead, Kemps ridley and hawksbill turtles as well as for human samples. Leatherback turtle samples show a dramatic nonlinear increased time below 23 °C, and green turtle sample responses were similar but less dramatic. All samples also showed increased prothrombin times as the pH decreased from 7.8 to 6.4, except for three turtle species. The prothrombin times decreased, to varying extents, in a linear fashion relative to reduced pH with the rate of change greatest in leatherbacks>greenloggerhead turtles. All studies were conducted with reagents developed for human samples which would impact on the quantitative results with the turtle samples, but are not likely to alter the qualitative results. These comparative studies of the coagulation pathway in sea turtles and humans could enhance our knowledge of structure/function relationships and evolution of coagulation factors.