The Study On Conservation Biology Of Green Sea Turtle (Chelonia Mydas) From South China Sea, China

Green sea turtle(Chelonia mydas) belongs to Reptilia, Chelonia, Cheloniidae. There are 2 families,5 categories and 7 species of sea turtles in the world. Green sea turtle(Chelonia mydas), Hawksbill (Eretmochelys imbricata), Pacific olive ridley (Lepidochelys olivacea), Loggerhead sea turtle(Caretta caretta), Atlantic lepidochelys olivacea(Lepidochelys kempii) and Flat back sea turtle(Natator depressus) belong to Cheloniidae; Leatherback sea turtle(Dermochelys coriacea) belongs to Dermoochelyoidea. Five species of sea turtles are distributed in China: green, hawksbill, loggerhead, leatherback, and olive ridley turtles. Green sea turtle is a kind of endangered species of marine migration. Sea turtles are distributed worldwide except in the Arctic waters. They have been recorded in the waters of the Chinese mainland coastal, but now mainly distributed in the South China Sea. The migratory of sea turtles has seasonal, purpose and fixed routes. The choice of breeding and feeding grounds has a high degree of accuracy. As China’s economic development, the green sea turtle populations fell sharply in the last 50 years. The breeding habitat of green sea turtle has been damaged seriously by human activities. The main threat factors are directly capture, fisheries bycatch, habitat destruction and environmental pollution. Green sea turtles have been listed in the convention on international trade in endangered species of wild fauna and flora, CITES appendix I list, has also been listed as national second-class protected animal in China.In this thesis, according to the literature, we investigated preliminary. But we did not find any green sea turtles. Therefore, we adopt the method of questionnaire survey to study the population status of green sea turtles, and used the method of field survey to study the nesting habitat conditions. According to the analysis of questionnaire and field survey, we found that the most important threat factor is directly capture.The most of directly capture of sea turtles entry into the channels of trade. We had researched the illegal trade of sea turtles via market survey and internet survey. This thesis collected tissue samples of 51 wild green sea turtles in the South China Sea, and extracting mitochondrial DNA of three genes (COI, Cytb and D-Loop) for studying the genetic diversity and genetic structure. Through the three aspects of research, this thesis put forward the protection of sea turtles in South China Sea targeted resources protection countermeasure and the suggestion.The main results of this thesis include:1. Green sea turtles were decreasing sharply from the South China Sea, now it is hard to see ashore laying eggs of green sea turtle, and the original breeding habitats are being destroyed.2. The main threat factors were directly capture and fishery bycatch in South China Sea. Which directly capture entry into the channel of trade. The fishery bycatch were trawl and gill net and commonly used fishing gear in the South China Sea.3. There is a lot of illegal trade of sea turtles on Chinese Mainland. Guangdong province is transit trade. Hainan province and Guangxi province is the source of trade market. Beijing and Shanghai is the regional trade center. In recent years, with the strengthening of law enforcement and the perfection of relevant laws and regulations, many illegal trade channels become more subtle. We need to monitor the quality of market, and expand more effective enforcement of the law.4. The green sea turtles from South China Sea have a high genetic diversity. The populations were not experienced a large expansion in the short term, but might experience a sharply decrease in a relatively short period of time. The population has communication with the populations from Indian Ocean and the Pacific Ocean. The migratory way may be the north to Japan and south to Malaysia and Australian waters.5. The protection about the green sea turtles from South China Sea is an important part of the world conservation. In order to protect the sea turtles resources better, we should build sea turtles conservation in South China Sea. We also should be launching satellite tracking, artificial breeding and scientific research.