• Animal Systematics, Evolution and Diversity
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• v.37 no.1
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• pp.9-14
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• 2021

Invasive species threaten global biodiversity as well as human livelihood and much of the global lands are vulnerable to these threats. Numerous freshwater turtles from the northern hemisphere have been introduced in East Asian countries, including the Republic of Korea. Knowing turtle's behavioral ecology is valuable to manage introduced populations and a distinctive behavior is basking for behavioral thermoregulation. To understand the possibility of using basking to enhance trapping, we tested thermotaxis in the river cooter (Pseudemys concinna). Turtles were placed in an aquarium containing heated and non-heated mats under controlled water and air temperature, air humidity and light. We found that P. concinna stayed significantly longer on heated mats than on unheated control mats in 11 out of 18 trials, demonstrating that heat source is a potential attractant for P. concinna. We recommend the use of heat source to bait traps used for population control of invasive freshwater turtles.

• Development and Reproduction
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• v.21 no.1
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• pp.101-110
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• 2017

On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were $25.9-36.9{\pm}0.5^{\circ}C$, the depth of the eggs was $5.2-7.5{\pm}0.5cm$ as the distance of the average $6.4{\pm}0.5cm$. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at $26.5-35.5{\pm}0.5^{\circ}C$, and an average constant temperature was $31.2-32.1{\pm}1.0^{\circ}C$. The incubation days ranged from 53 to 55. In case of most turtles, incubation at $31^{\circ}C$ (higher temperatures) generally produces all or mostly females, while incubation at $25^{\circ}C$(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination.

• Applied Microscopy
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• v.19 no.2
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• pp.119-137
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• 1989

It has been shown in this and earlier investigation that the turtle bladder mucosa has three main cell types on their mucosal surface. They are the granular cells, ${\alpha}$ CA cells, and ${\beta}$ CA cells. The three major transport mechanisms that occurs in the turtle bladder are sodium reabsorption, proton secretion, and bicarbonate secretion. In the present work the trans-port mechanisms by bladder epithelial cells of freshwater turtle, Pseudemys scripta, are summarized as follows. 1. The granular cells play an important role in sodium transport, while the ${\alpha}$ and ${\beta}$ CA cells do not appear to play a determining role in sodium transport. 2. It appears that the active sodium transport in the granular cells occurs in two-step process, implying that first, sodium diffuses into the cells, followed by an energy-dependent efflux step, which is catalyzed by the ouabain-sensitive Na-K ATPase. 3. The ${\alpha}$ type of CA cells are responsible for the proton secretion using the proton pump on the apical plasma membrane, while the ${\beta}$ type of CA cells are believed to be responsible for bicarbonate secretion. 4. When looked at under freeze-fracture electron microscopy, the apical plasma membrane of ${\alpha}$ cells have a characteristic population of rod-shaped intramembranous particles which are believed to be components of the proton pumps. Conversely, ${\beta}$ type of CA cells show rod-shaped particles in their basolateral plasma membranes, which is consistent with the proton absorptive, bicarbonate secretory mechanism. 5. In the turtle bladder, the ${\alpha}$ and ${\beta}$ type of cells are believed to be both responsible for proton transport, but in opposite directions.

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.204.2-205
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• 2001

No Abstract, See Full Text

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.970-976
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• 2016

Determining age structure of the population of an endangered species is critical because it could provide basic information about population dynamics. In this study, we assessed the possibility if the growth lines on dorsal scutes of the national monument as well as endangered Reeves' turtle (Mauremys reevesii) can reliably estimate actual ages of the 100 turtles of which actual ages were known and have been housed in Seoul Zoo. We counted the number of growth lines on the first four dorsal scutes and the first left and right lateral scutes of each turtle and compared those with their known actual ages. Ages estimated by the growth lines were overestimated at between 1 and 5 actual ages, but underestimated at between 6 and 9 actual ages, indicating that age estimation using growth lines is only partially applicable at actual ages of less than 6 years old. In addition, using length and width of turtle's dorsal plates, we produced growth curves with equations to estimate actual ages of females combined with juveniles, but its application to estimate actual ages was not reliably possible because all subject turtles which used were at relatively young ages. In conclusion, when estimating actual ages of Reeves' turtles using the number of growth lines on the dorsal scutes, it is recommend to use minimum values at less than 6 lines, but use maximum values at more than 7 lines. As the first study which estimated actual ages of a turtle species using growth lines on the dorsal scutes in Korea, our results could be useful to estimate ages of the endangered Reeve's turtles in the field although its application might be limited.

• Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.107-114
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• 2006

A dermal sarcoma was found in a freshwater, soft-shelled turtle Pelodiscus sinensis. The neoplasm consisted of proliferating fibrous tissue and extended from the dermis. The overlying epidermis was hyperplastic and partially folded. The deeper dermis and hypodermis contained three large, discrete necrotic foci of -10 mm diameter. Numerous eosinophilic granule cells and macro phages surrounded the necrotic areas. A mixed population of cells with nuclear pleomorphism was observed between the papillary layers of vessels. This area also had regions of different histological structures: (l) regularly arranged, spindle-shaped cells with compact nuclei in a fine-fibrillar matrix; (2) haphazardly arranged cells ($\leq$ 23 11m diameter) with ovoid, highly hypertrophic, faintly stained nuclei; and (3) cells (3.6-5.8 11m diameter) with irregularly shaped nuclei and marginal condensed chromatin in a myxomatous matrix. Some mitotic figures, binucleate cells, and multinucleate giant cells of up to 50 11m in length were also found. Flow cytometry of propidium iodide-stained cells yielded different histograms for the normal skin and the skin (primarily epidermis) and fibrous dermis of the tumor, indicating DNA heterogeneity in the dermal portion of the tumor. The ploidy indices for the dermal cells were 1.91 and 0.78, as compared to normal cells.

• Journal of Korean Home Economics Education Association
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• v.12 no.2
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• pp.47-64
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• 2000

The purpose of this study was to search the calcium and iron rich foods in Korean people. The food sources presented in the current home economics textbooks of middle and high school were investigated. And 40 kinds of calcium and iron rich foods were selected by the quantity in 100g edible portion. one serving size and according to 1997 food supply data. Also 3 major food groups of calcium and iron supply in Korean were identified, and 10 rich foods for each food groups were selected. The results were summarized as follows. 1. The food sources of calcium 1) The food sources of calcium presented in the home economics textbooks of middle and high school are milk and dairy products. small fishes such as anchovy icefish and dried strip and green vegetables etc. 2) The calcium rich foods by 100g edible portion were in order of skim milk powder river snail sesame sea mustard. whole milk powder. snapping turtle loach sea tangle(dried) opossum shrimp and sea lettuce(dried). And the calcium rich foods by the calcium content in one serving were in order of river snail snapping turtle opossum shrimp loach spiny lobster skate skim milk powder small alaska pollack freshwater crab condensed milk whole milk powder skate ray and milk. 3) The 3 major calcium supply food groups in Korean were vegetables fish and shellfishes and milk and dairy products. 4) The calcium supply foods according to the quantity of food supply in 1997 was in order of sea mustard, milk anchovy chinese cabbage soybean skin milk powder laver shrimp welsh onion and maize. The vegetables were the important sources of calcium in Korean. 2. The food sources of iron 1) The food sources of iron which are commonly presented in the textbooks of middle and high school were meat liver egg(egg yolk) and green vegetables etc 2) The iron rich foods on the basis of the iron content in 100g edible portion were in order of surf clam marsh clam laver(dried)( sea lettuce(dried), crayfish pelilla seed little neck clam orient hard clam, venus clam, and freshwater carab. And the iron rich foods by the iron content in one serving were in order of surf clam marsh clam crayfish little neck clam orient hard clam freshwater crab venus clam hen cockle green confertii(fresh) pen shell and spiny lobster. 3) The 3 major iron supply food groups in Korean were cereals an cereal products fishes and shellfishes and vegetables. 4) The iron supply food according to the quantity of food supply in 1997 was in order of soybean sea mustard maize rice meat edible viscera laver wheat flour, pook, red pepper, egg and bovine meat.

• Korean Journal of Environmental Biology
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• v.35 no.1
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• pp.57-63
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• 2017

This study was conducted to determined the status and geographical distribution of the alien invasive Red-eared slider (Trachemys scripta elegans) turtle on Jeju Island. We found thirty-two Red-eared slider habitats including twenty-five ponds, five agricultural reservoirs, a puddle and a stream. Among those, thirteen sites are newly determined habitats of the turtle. The remaining nineteen are previously reported. However, we could not find any turtles at nine sites, which were documented as turtle habitats in earlier reports. A total of one hundred thirty-three turtles were observed. Among them, we determined that thirty-nine were juvenile turtles, found in nineteen different habitats, indicating estimating that Red-eared sliders produced their progeny in the wild of this island. Because of geographical isolation by the ocean, no freshwater turtle had been found until $19^{th}$ Century. Therefore, the increased number of finding sites and Red-eared sliders indicate the possibility of human release of their pets or for other purposes, and natural propagation in the wild on Jeju Island. Our findings will be useful for management planning to deal with this invasive species, and implementation of a conservation program for native wildlife on Jeju Island.

• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.138-144
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• 2023

The main factor of biodiversity decline in major biological populations around the world is invasion of alien species. To protect native species, it is necessary to manage alien species. Recently, to eradicate ecosystem disturbance caused by alien species in Korea, many efforts have been made to capture individuals using nets and purchase captured individuals. However, there is no standard for classifying species due to the form of nest site or external characteristics of eggs of freshwater turtles. Thus, Mauremys reevesii eggs might be discarded due to mistaking as eggs of alien turtles. Based on more data, this study aims to compare and analyze external differences among eggs of Trachemys scripta elegans, Pseudemys concinna, and M. reevesii and use them as reference materials in the process of eradicating alien turtles. This study measured characteristics of eggs of the three turtle species. As a result of comparison, all variables of external characteristics of alien turtles and M. reevesii eggs showed significant differences. The shape of egg was also different, with eggs of T. scripta elegans and P. concinna showing a bicone shape and those of M. reevesii showing an ellipsoid shape. In conclusion, based on results of previous studies and the present study, eggs of M. reevesii, T. scripta elegans, and P. concinna are different in shape and structure. Thus, it is possible to distinguish between M. reevesii and invasive alien turtle using their eggs.

• 한국생태학회:학술대회논문집
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• 1999.05a
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• pp.43-54
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• 1999

1. Hanoi city was built up on the wetland landscape of the Red River delta therefore it has a network of many lakes and rivers. 2. The aquatic biodiversity (Macrophytes, Invertebrates, Fishes, Vertebrates) of the 6 main lakes (Ho Tay, Hoan Kiem, Bay Mau, Giang Vo, Dong Da, Thanh Nhan) are rich and diverse. It represents the patterns of Red River delta one's. Many rare and endangered species are found in these lakes Particularly a giant freshwater turtle species in Hoan Kiem lake. 3. All of these lakes are more or less polluted. Their environments are seriously degrading both in water quality and aquatic biodiversity. 4. Based on socio-economical and cultural role of these lakes of Hanoi city, it is very necessary to preserve and to restore their environments and aquatic biodiversity: water Pollution control, landscape planning, making roads around the lakes and erosion control for their banks, legislation measures, rational exploitation of aquatic biodiversity, restoration the artificial wetlands with macrophytes.