Preliminary data of three zoobenthos groups (brachyura, gastropoda and bivalviva) found in the mangrove forest ecosystems of the tran de estuary, Soc Trang province

Until now, data on zoobenthos in the Mekong Delta has been very limited. Prior research has focused mostly on species of economic value such as the Red chut-chut snails. In this research, we investigated species composition and distribution of Brachyura, Bivals and Gastropods in the Tran De Estuary Mangrove forests in Soc Trang province between June and December, 2011, to discover the extent of zoobenthos biodiversity.
Nội dung trích xuất từ tài liệu:
Preliminary data of three zoobenthos groups (brachyura, gastropoda and bivalviva) found in the mangrove forest ecosystems of the tran de estuary, Soc Trang province JOURNAL OF SCIENCE OF HNUE Chemical and Biological Sci., 2012, Vol. 57, No. 8, pp. 72-80 This paper is available online at http://stdb.hnue.edu.vn PRELIMINARY DATA OF THREE ZOOBENTHOS GROUPS (BRACHYURA, GASTROPODA AND BIVALVIVA) FOUND IN THE MANGROVE FOREST ECOSYSTEMS OF THE TRAN DE ESTUARY, SOC TRANG PROVINCE Hoang Ngoc Khac1 , Do Van Nhuong2 Nguyen Thanh Tung3 and Nguyen Thi Thu Huong3 1 Hanoi University of Natural Resources and Environment 2 Faculty of Biology, Hanoi National University of Education 3 Faculty of Biology, Can Tho University Abstract. The Tran De Estuary Mangrove (TDEM) forests are located in the Cu Lao Dung and Tran De districts in Soc Trang Province. The research for zoobenthos has resulted in the identification of 73 species and 32 families from 54 genera in the ecosystem of the Tran De mangrove estuaries in Soc Trang Province. There are 34 species of Brachyura belonging to 21 genera of 9 families; of Gastropoda were found 22 species of 16 genera and 9 families; and of Bivalvia there were 17 species of 17 genera in 14 families. Of these, eight were recorded for the first time in Vietnam. They are: the Blue fiddle crab (Uca urvillei), the Pinkfingered vinegar crab (Neoepisesarma chentongensis), the Red-clawed mangrove crab (Pseudosesarma bocourti), the Mangrove tree-dwelling crab (Selatium brocki), the Flower crab (Sesarmops intermedius), the Black mouth nerite (Neritina cornucopia), the Singapore mangrove helmet (Melampus singaporensis) and Trigonal pythia (Pythia trigona). Of the zoobenthos fauna found in this area, many are found in the India–Malaysia region. One of these is the Vinegar crab (Neoepisesarma). Besides the mud crab (Scylla olivacea), there are 7 species which are large enough to be used as human food. In particular, Vinegar crabs (Neoepisesarma) are captured and used as an ingredient in BaKhia sauce. Keywords: Zoobenthos, Brachyura, Gastropoda, Bivalvia, Mangrove, Soc Trang, Vietnam.1. Introduction The Tran De Estuary Mangrove (TDEM) forests are located in Cu Lao Dungand Tran De districts in Soc Trang Province. TDEM forests make up a total area ofReceived June 4, 2012. Accepted August 23, 2012.Contact Do Van Nhuong, e-mail address: dvnhuong@hotmail.com72 Preliminary data of three zoobenthos groups (Brachyura, Gastropoda and Bivalviva)...approximately 2263 ha with a uneven width of 150 - 1800 m. Lying at the mouth of theHau River, TDEM receives a substantial amount of sediment from upstream and annuallyextends out 20 - 50 m into the sea. Of alluvial nature, the substrate consists of clay, silt,sand, mud and sand, a mixture of organic sediment of land and ocean. Salinity variesfrom 5 - 29 %, depending on both the distance from the mouth and the season. The canalsystem is influenced by semidiurnal tides regime with average amplitude ranging between0.4 - 1.0 m. Like most mangrove forests in Vietnam, a substantial propotion of TDEM is newlyrehabilitated. TDEM has highly diverse flora of which Mangrove Apple (Sonnertiacaseolaris) is dominant. Other species found are Grey mangrove (Avicennia marina), RedMangrove (Rhizophora stylosa), a shrub layer consisting of Nipa (Nypa fruticans), Threeleaf Derris (Derris trifoliate) and Sea holly (Acanthus ilicifolius). Outside of the alluvialplain, most of the Sonnertia caseolaris has been planted and a shrub layer is rarely found,that substrate layer being almost empty. Until now, data on zoobenthos in the Mekong Delta has been very limited. Priorresearch has focused mostly on species of economic value such as the Red chut-chutsnails [5, 8, 9]. In this research, we investigated species composition and distributionof Brachyura, Bivals and Gastropods in the Tran De Estuary Mangrove forests in SocTrang province between June and December, 2011, to discover the extent of zoobenthosbiodiversity.2. Content2.1. Materials and methods Samples were collected in benthic habitats inside, outside and adjacent to mangroveforests, and also along the canal and on muddy flats on which were growing no mangrovetrees. Most crab specimens were obtained by digging them up while the rest werecaptured using traps. Some bivals specimens were dug up while other bivals and allgastropods specimens were collected by hand. Tiny specimens were captured using asieve. Specimens from each site were put in separate plastic bags or bottles and labeled. Those samples were fixed in a 4% fo ...