Acceptance of the research project “Studying and applying ex-situ conservation method to restore and conserve the giant clam species Tridacna squamosal Lamarck in Con Dao”
22/11/2017
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On January 17th, the Department of Science and Technology organized an advisory council to evaluate the provincial research project “Studying and applying ex-situ conservation method to restore and conserve the giant clam species Tridacna squamosal Lamarck in Con Dao in 2014-1016”. The research was lead by Eng. Nguyen Duc Thang and hosted by the the Management Committee of Con Dao National Park”
The objective of the project is to studying the application of ex-situ conservation (off-site conversation) to restore and conserve the giant clam species in natural environment, contributing to marine biodiversity and sustainable development of fisheries sector of Vietnam.
Con Dao is an archipelago of 16 islands located on the southeast of Ba Ria – Vung Tau province at the distance of 179 km from the coastal city Vung Tau. Con Dao waters have the three marine ecosystems, namely mangrove ecosystem, seagrass ecosystem, coral reef ecosystem. There are a total of 1,723 sea creatures including 72 rare and endangered species listed on Vietnam Red Data Book and IUCN Red List such as sea turtles, dolphins… Restoration and conservation of forest ecosystems, marine ecosystems, biodiversity of local flora and fauna and natural habitats unique to Con Dao Con Dao national Park are important as the island aims to become an important center for biodiversity conservation national and worldwide.
After two years of project implementation, survey of the distribution of the species and initial study of biological characteristics were conducted. The project relocated 90 giant clams with shell length curve (SCL) of more than or equal to 20 centimeters from the adjacent waters to three experimental conservation areas. The survey result showed that the density at surrounding waters averaging one individual per every nearly 2000 meters square. The further it goes from the islands, the density is lower as distant areas get little presence of sea rangers. With the density of matured individuals lower than 2000 meters square per instance, chance for sperms to meet eggs gets very low hence density of offspring (SCL<20m2) recorded are small. This imbalance causes a gradual loss of population and imposes a high risk of extinction in the near future.
With the preservation work, individuals moved to conservation areas recorded a shell growth by 5,4 centimeters after 21 months. One young claim was discovered near Hon Tre Lon conservation area. The survival rate of relocated population at the three conservation areas is above 94% in 21 months, showing that the ecological environment at these new areas is as favorable as in the wild.
According to the acceptance council, the study gives basis for proposing the development of the most suitable model to preserve seeds of Tridacna squamosal Lamarck clam and provide favorable condition for the growth of the claim species in Con Dao. The study is important to provide knowledge and practice to protect and maintain gene bank of Con Dao coral reefs and of other similar beaches across Vietnam. The Council agreed to accept the research project as completed and graded it as good.
