• Journal of Ecology and Environment
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• 제45권4호
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• pp.203-217
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• 2021

Background: Sea turtles, which are globally endangered species, have been stranded and found as bycatch on the Korean shore recently. More studies on sea turtles in Korea are necessary to aid their conservation. To investigate the spatio-temporal occurrence patterns of sea turtles on the Korean shore, we recorded sampling locations and dates, identified species and sexes and measured sizes (maximum curved carapace length; CCL) of collected sea turtles from the year 2014 to 2020. For an analysis of diets through stomach contents, we identified the morphology of the remaining food and extracted DNA, followed by amplification, cloning, and sequencing. Results: A total of 62 stranded or bycaught sea turtle samples were collected from the Korean shores during the study period. There were 36 loggerhead turtles, which were the dominant species, followed by 19 green turtles, three hawksbill turtles, two olive ridley turtles, and two leatherback turtles. The highest numbers were collected in the year 2017 and during summer among the seasons. In terms of locations, most sea turtles were collected from the East Sea, especially from Pohang. Comparing the sizes of collected sea turtles according to species, the average CCL of loggerhead turtles was 79.8 cm, of green turtles was 73.5 cm, and of the relatively large leatherback turtle species was 126.2 cm. In most species, the proportion of females was higher than that of males and juveniles, and was more than 70% across all the species. Food remains were morphologically identified from 19 stomachs, mainly at class level. Seaweeds were abundant in stomachs of green turtles, and Bivalvia was the most detected food item in loggerhead turtles. Based on DNA analysis, food items from a total of 26 stomachs were identified to the species or genus level. The gulfweed, Sargassum thunbergii, and the kelp species, Saccharina japonica, were frequently detected from the stomachs of green turtles and the jellyfish, Cyanea nozakii, the swimming crab, Portunus trituberculatus, and kelps had high frequencies of occurrences in loggerhead turtles. Conclusions: Our findings support those of previous studies suggesting that sea turtles are steadily appearing in the Korean sea. In addition, we verified that fish and seaweed, which inhabit the Korean sea, are frequently detected in the stomach of sea turtles. Accordingly, there is a possibility that sea turtles use the Korean sea as feeding grounds and habitats. These results can serve as basic data for the conservation of globally endangered sea turtles.

• Journal of Ecology and Environment
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• 제33권3호
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• pp.237-244
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• 2010

In this study, we evaluated the distribution, habitat characteristics, and diet of two Korean freshwater turtle species (Chinemys reevesii, Pelodiscus sinensis) and an invasive turtle species (Trachemys scripta elegans) in the area surrounding the Seomjin River and the Nam River. We surveyed basking turtles in multiple locations along a 48-km stretch of the Seomjin River and in 99 reservoirs distributed along the Seomjin and Nam rivers from June to September, 2009. We observed 8 and 6 red-eared turtles in 3 reservoirs and at 3 sites in the Seomjin River, respectively, and 33 Reeve's turtles in 9 reservoirs. There were also 28 and 16 mud turtles detected at 15 sites along the Seomjin River and in 8 reservoirs, respectively. Among the 14 biotic and abiotic habitat characteristics that might influence the abundance of freshwater turtles in reservoirs, only the distance between a reservoir and the nearest residential areas was correlated negatively with abundance. With regard to the diet, all Reeve's and red-eared turtles investigated were determined to forage on water snails. Some turtles also foraged on vegetation and aquatic invertebrates. Additionally, we found fish in the stomach of one of the Reeve's turtles, and dragonflies in the stomachs of two red-eared turtles.

• 수산해양교육연구
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• 제29권3호
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• pp.702-710
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• 2017

Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

• 환경생물
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• 제30권2호
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• pp.151-155
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• 2012

Korean freshwater turtles are divided into native turtles, Chinemys reevesii in Geoemydidae, Pelodiscus sinensis in Trionychidae, and imported turtles, Trachemys scripta elegans, T. s. scripta, Pseudemys rubriventris and Ocadia sinensis. In this study, we determined the distribution of Korean freshwater turtles based on a field study and literature study, and considered the taxonomic position of unidentified native turtles. The study was carried out between May 2010 and November 2011 during the day time, and the capturing tool used to collect turtles consisted of net and metal frame. C. reevesii and P. sinensis were found in 16 and 11 places, respectively. C. reevesii, which inhabits the Korean peninsula, is a taxonomically controversial species, but it is presumed that the turtle belongs to Mauremys. Moreover recent taxonomic studies of the soft-shell turtle have shown that the Korean native species is P. maackii, and P. sinensis was imported from abroad and has been in the natural habitats of Korea since 1970s. The exterior shape and skeletal form of P. maackii and P. sinensis are nearly similar. However, the skin color and yellow spots on the shell could be used to distinguish the two species.

• 한국수산과학회지
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• 제42권6호
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• pp.657-663
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• 2009

This paper reports the strandings of sea turtles on Korean shores monitored for the first time in 2008. A total of 19 sea turtles, consisting of 12 greens and 7 loggerheads, were recorded as stranded from the east coast to the south including Jeju Island. Reported strandings reached a peak in July and dominant area was Jeju Island. The curved carapace length of loggerhead sea turtles ranged 65-84.2cm and that of green sea turtles ranged 39.2-90cm, indicating most of them were immature to sub-adult. Out of 19 turtles, 11 were found dead with unknown reasons. Possible causes of death may include drawning by fishing gear, swallowing of marine debris, boat collision, and diseases. An immature green sea turtle tagged with a satellite transmitter spent winter near Jeju Island where it was released, suggesting that the Island provide immature greens a feeding ground. Considering thousands of sea turtles crawl on Japanese shores for nesting every year, the number of sea turtles reported in Korean waters was relatively small. Therefore, it is suggested that an appropriate monitoring system be necessary to protect and conserve endangered sea turtle species in Korean waters.

• 통합자연과학논문집
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• 제16권4호
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• pp.111-122
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• 2023

Invasive species are organisms that are introduced into places outside of their natural distribution range. The global pet trade is facilitating the introduction of invasive species into new countries and areas. Among the introduced alien species, turtles are one of the most common animal groups whether lives in wetland ecosystems, such as wetlands or reservoirs. Like other countries around the world, exotic turtles is becoming a growing concern for the wetland ecosystem in South Korea. In this study, we report new reports of subspecies of Painted turtle (Chrysemys spp.): Chrysemys picta marginata, C. p. bellii and C. dorsalis, from the reservoirs in downtown Cheongju and Gwangju, South Korea. We used morphological features, such as the characteristics of the legs, plastron, and carapace, to identify the turtles. It is assumed that all turtles were artificially released into nature. Considering the increasing number of reports on the introduction of alien invasive turtles in Korean wetlands, we recommend the formulation of an immediate and systematic management plan for pet trades and organized continuous monitoring programs.

• 한국동물위생학회지
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• 제40권1호
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• pp.27-33
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• 2017

Salmonella enterica subsp. enterica is a common microbial flora in pet turtles, which could opportunistically become pathogenic to human. Their possession of aminoglycoside resistance genes has important significance both in humans and animal medicine. In this study, twenty-one Salmonella enterica subsp. enterica were isolated from thirty-five individual turtles purchased from pet shops and online markets in Korea. In order to characterize the aminoglycoside susceptibility patterns, antimicrobial susceptibility tests were performed against gentamicin, amikacin and kanamycin of aminoglycoside antimicrobial group. Each of the isolates showed susceptibility to all tested aminoglycosides in disk diffusion and minimum inhibitory concentration (MIC) tests. PCR assay was carried out to determine aminoglycoside resistance genes, integron and integron mediated aminoglycoside genes. None of the isolates showed aac(3)-IIa, aac-(6')-Ib, armA, aphAI-IAB aminoglycoside resistance genes. Only, five isolates (24%) harbored class 1 integron related IntI1 integrase gene. The results suggest that Salmonella enterica subsp. enterica strains isolated from pet turtles are less resistance to aminoglycosides and don't harbor any aminoglycosides resistance genes.

• Animal cells and systems
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• 제2권2호
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• pp.177-181
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• 1998

Blood samples collected from green (chelonia mydas), loggerhead (caretta caretta), and Kemp's ridley (Lepidochelys kempii) sea turtles were analyzed by radioimmunoassay to detect seasonal variations in thyroid hormones and compare levels in wild and captive individuals. Sexual dimorphism in the annual cycle of thyroxine was observed in adult Kemp's ridley. No differences were observed between immature male and female green and loggerhead sea turtles. The level of triiodothyronine was consistently low relative to thyroxine in all species investigated, and captive sea turtles exhibit higher plasms thyroid levels than do wild ones.

• 환경영향평가
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• 제25권5호
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• pp.319-332
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• 2016

붉은귀거북(Trachemys) 속 전종이 2001년 환경부의 생태계교란생물로 지정되어 수입이 금지되어 있지만 대부분의 외래거북 국내 도입과 자연생태계 서식 현황은 아직까지 알려지지 않았다. 본 연구는 국내에 도입된 외래거북의 종류와 서식 실태를 밝히고 자연생태계에 대한 영향 및 향후 관리방향을 제시하고자 수행되었다. 외래거북은 국내에 총 9과 73종이 도입되었으며, 2008년 이후 연간 6,000kg 이상의 거북이 수입되어 동물판매업체와 재래시장, 개인 간 거래를 이용하여 전국적으로 유통되었다. 자연생태계 서식현황을 조사한 결과, Chrysemys picta, Pseudemys concinna, P. nelsoni, P. peninsularis, P. rubriventris, Mauremys sinensis, Macrochelys temminckii, Trachemys scripta 등 3과 8종이 발견되었다. 국내에 도입된 외래거북 중 국외의 침입외래생물 관리 및 지정 현황을 검토하여 자라과(Trionychidae), 남생이과(Geoemydidae), 늪거북과(Emydidae), 늑대거북과(Chelydridae)에 속하는 4과 13종을 외부 유출과 자연생태계 유입 관리가 필요한 외래거북으로 구분했다. 외래거북의 효과적 관리를 위해서는, 수입되는 외래거북은 수입목록에 등재하고, 수입목적, 유통, 관리실태 등 종합적인 정보를 관련 기관에서 공유해야 한다. 사육 및 유통자는 거북의 식별조치 및 관리기록을 의무화하고 관리기관은 거북의 이동 및 양도 상황을 주기적으로 점검하여 유입과 확산을 조기에 제어할 필요가 있다. 그리고 자연 서식하는 외래거북 개체군의 변화를 정기적으로 조사하고, 확산으로 인한 생태적 영향이 큰 도서지역 및 생태경관보전지역 등의 지역에서는 즉각적인 관리계획을 수립하여 시행하는 등 적극적인 대응이 필요하다. 또한, 국내 유입된 외래거북은 생태계에 대한 정기적 위해성평가를 통해 필요시 생태계교란 생물로 지정하고, 본 연구에서 외부 유출 및 자연생태계에 대한 유입관리가 필요한 것으로 제시한 4과 13종을 포함한 자연생태계 미유입 외래거북은 필요시 위해우려종에 포함하는 등 법제적 관리를 검토할 필요가 있다.

• 생태와환경
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• 제50권3호
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• pp.286-294
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• 2017

교통수단의 발달은 국가 간의 장벽을 빠르게 낮추고 있지만 이는 과거보다 쉬운 생물종 이동의 원인으로 작용하고 있다. 특히 수 많은 종류의 외래생물들이 식량과 가죽, 애완 등의 목적으로 수입되고 있으며, 인위적 혹은 자연적으로 야생에 유입되어 생태계 교란의 주범이 되고 있다. 본 연구에서는 대표적인 외래생물종인 붉은귀거북을 비롯한 외래거북을 대상으로 국내 생태계로의 유입현황을 파악하고, 이들의 분포 특성을 분석하고자 하였다. 강원도와 경상남도 지역에 위치한 총 126개의 저수지를 조사한 결과, 총 4속 8종 62개체의 외래거북들이 발견되었다. 그중 붉은귀거북의 발견 빈도가 상대적으로 높았으며, 일부 지역에서는 붉은귀거북의 자연 번식도 이루어지고 있는 것으로 확인되었다. 반면, 붉은귀거북을 제외한 다른 외래거북들의 발견 빈도는 비교적 낮았으며, 발견되는 지역의 범위는 제한적이었다. 특히 외래거북들은 공원 내 저수지와 같은 일반인의 접근이 비교적 높은 곳에서 주로 발견되었다. 지리정보시스템을 이용한 외래거북의 분포 특성을 분석한 결과, 외래거북의 발견은 시가지라는 인위적인 요소와 높은 연관성을 보였다. 이러한 연구 결과는 생태계에 유입되어 있는 외래거북류의 현황 파악과 동시에 이들을 효과적으로 관리하기 위한 방안을 수립의 중요한 근거가 될 것이다.