• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.662-669
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• 2012

Bycatch and stranding of sea turtles from Jeju coastal water of Korea were monitered from 2008 to 2009. A total of 41 sea turtles, consisting of 12 greens (Chelonia mydas), 3 loggerheads (Caretta caretta), 1 hawksbill (Eretmochelys imbricata) and 25 unidentified species, were recorded and observed in those area. Reported stranding and bycatch reached to a peak in August. The largest number of bycatch occurred in the coastal waters around Aewol-eup located in northwest area of Jeju Island. Most of the bycatch were taken by set nets and gill nets, which prevailed over the fishing grounds in the coastal waters of the Jeju Island. It is suggested that an appropriate monitoring system be necessary to conserve endangered sea turtle species in Jeju of Korea.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.917-926
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• 2022

The green turtle Chelonia mydas has been designated as an endangered species globally due to its reduced population. Although C. mydas is not known to reproduce on the shores of the Korean peninsula, it has been listed as a protected marine species in South Korea. This study describes the first successful captive breeding of C. mydas in a commercial aquarium in South Korea and provides information on the early growth patterns of C. mydas hatched and reared in indoor facilities. C. mydas YS-B003 laid a total of 594 eggs in ten nesting events in the period December 2016-June 2017. Of these, 115 fertilized eggs from six events hatched successfully. The size of the newly hatched turtles differed significantly among nesting events. The hatchlings from the 8^th and 9^th nesting events were relatively smaller than those from the 3^rd and 5^th events. The rate of growth initially varied across the different events, but from the 1,000^th day, the inter-group variation disappeared. The present study provides useful information for future captive breeding of sea turtles in indoor facilities, which would contribute to the protection of these endangered sea turtle species.

• Journal of Aquaculture
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• v.20 no.1
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• pp.60-64
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• 2007

We examined the effects of the vibration stress on oxygen consumption and ammonia excretion of cultured soft-shelled turtle, Pelodiscus sinensis. For the stressed group vibration of $45{\sim}78\;dB$ (V) from electric vibrator was turned on for 15 min with 2-h intervals during daytime hours ($08:00{\sim}18:00$) for 28 days. Two different sizes of soft-shelled turtle, large (carapace length: $12{\sim}16\;cm$, body weight: $300{\sim}600\;g$, large size turtle: LST) and middle ($16{\sim}20\;cm,\;700{\sim}1,000\;g$, middle size turtle: MST) were used. The oxygen consumption of LST the beginning of the experiment (1 day) was 124.30 mg $O_2/kg/hr$, and after 7, 14, 21 and 28 days of stress decreased by 47.2, 71.6, 79.1 and 86.0%, respectively. In MST, oxygen consumption of beginning day was 66.04 mg $O_2/kg/hr$, and after 28 days of stress decreased by 76.5%. Ammonia nitrogen excretion showed a similar pattern to that of oxygen consumption. Ammonia nitrogen excretion of beginning of the experiment was 0.537 mg N/kg/hr, and after 28 days of stress decreased by 75.4% for LST, and by 74.3% for the middle ones. From in this study it was showed that the physiological activity was reduced by 50% following 8.4 days of vibration stress for LST, and 15.5 days for MST.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.89-89
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• 2017

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.226-229
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• 2007

Survival, tag retention and tag readability were compared among the control and three treatment groups of soft-shelled turtles, Pelodiscus sinensis Crother, 2000 (mean body $weight{\pm}SD$: $182.6{\pm}13.7\;g$), marked with visible implant fluorescent elastomer (VIFE) tags for 16 months. Mortality 4 to 16 months after tagging was attributed to collection and handling stress rather than to the tagging itself. Tags applied to the web surface between the fourth and fifth dactyl of the hindfoot appeared to have the highest retention rates, while adipose eyelid tagging had high tag readability but a high loss rate. We conclude that in soft-shelled turtles, the most suitable region for VIFE tagging is on the web surface between the fourth and fifth dactyls of the hindfoot.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.49-55
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• 2010

In vitro cultivation of trematodes would assist studies on the basic biology of the parasites and their hosts. This is the first study to use the yolk of unfertilized chicken eggs as a simple and successful method of ovocultivation and the first time to obtain the adult-stage of the trematode Cymatocarpus solearis Braun, 1899 (Digenea: Brachycoeliidae). Chicken eggs were inoculated with metacercariae from the muscle of the spiny lobster, Panulirus argus (Latreille, 1804). The metacercariae were excysted and incubated for 576 hr (24 days) at $38^{\circ}C$ to obtain the adult stage. Eggs in utero were normal in shape and light brown color. The metacercariae developed into mature parasites that have been identified as the adultstage found in marine turtles. The adult lobsters collected in Quintana Roo State, Mexico, showed the prevalence of 49.4% and the mean intensity of 26.0 per host (n=87). A statistical study was performed to determine that no parasitic preference was detected for male versus female parasitized lobsters. Morphometric measurements of the adult-stage of C. solearis obtained in our study have been deposited in the National Helminths Collection of the Institute of Biology of the National Autonomous University of Mexico. This study is significant because it is the first time that a digenean of the family Brachycoeliidae has been demonstrated to develop in vitro from metacercariae into adults capable of producing eggs using the yolk of unfertilized chicken eggs. Secondly, this technique allows to obtain the adult stage of C. solearis without the presence of its marine turtle host, allows us to describe the mature parasites, and thus contribute to our understanding of the biology of C. solearis.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.117-122
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• 2000

In these days, the pollution of marine environment near island at Korean coastal zone caused by the trash, human waste and livestocks excreta become series problem. One of the most economic and efficient way to prevent this pollution problem is to set up island circulating incineration system. In this paper, the results of feasibility study on the application of turtle boat hull form to the incinearting vessel has been summarized especially for the resistance and course keeping point of view.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.95-99
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• 1997

In these days, the pollution of marine environment near island at Korean coastal zone caused by the trash human waste and livestocks excreata become intensified. One of the most economic and efficient way to prevent this pollution problem is to set up island circulating incineration system. In this paper, the result of feasibility study on the application of turtle boat hull form to the incinerating vessel has been summarized especially for the resistance and course keeping point of view.

• Preventive Nutrition and Food Science
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• v.20 no.2
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• pp.133-136
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• 2015

Freshwater softshell turtle (Trionyx sinensis) extract has been used traditionally as a tonic soup, and to recover from physical fatigue. To support these claims, the forelimb grip strength of mice was measured after feeding a soft-shell turtle extract for 7 days. The T. sinensis extract significantly increased the grip strength to $1.25{\pm}0.07N$ (P<0.01), which is 16.8% higher than the force on day 0. After exercising, the blood glucose levels in extract-fed mice were 202% higher and urea levels were 73% lower, which were both significantly different than the levels observed after control treatment. Lactate dehydrogenase was significantly higher by 314%, and glutathione peroxidase increased by 165%. In addition, the obesity markers, serum triglyceride and cholesterol, decreased to 62% and 49%, respectively, after mice were fed the extract. These data show that the T. sinensis extract provided more energy for forelimb exercise, prevented protein catabolism and muscle fatigue, and decreased the oxidative stress caused by an exhaustive workout.