MINISTRY OF EDUCATION VIETNAM ACADEMY AND TRAINING OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY NGUYEN VAN GIANG RESEARCH ON THE FISH FAUNA OF THE BANG GIANG – KY CUNG RIVER BASIN IN VIETNAM SUMMARY OF BIOLOGICAL DOCTRINE THESIS HA NOI – 2018 The work was completed at: Graduate University Science and Technology - Vietnam Academy of Science and Technology Supervisors 1: Assoc.Prof. Dr. Nguyen Huu Duc Supervisors 2: Dr. Nguyen Kim Son Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be protected before the examination of PhD thesis at the Academy, meeting at the Graduate University Science and Technology - Vietnam Academy of Science and Technology at ... hour .... ', Date ... month ... 2018 The thesis can be found at: - Library of the Graduate University Science and Technology - National Library of Vietnam 1 INTRODUCTION 1. The urgency of the thesis Annually, the river basin of Ky Cung - Bang Giang provide important fisheries to the people of Lang Son and Cao Bang, provides the main source of protein from fish in the daily meals in each family. Though, So far no work has systematically studied the fish fauna here. Besides that, the conservation of rare genetic resources and biodiversity in the Bang Giang - Ky Cung River is a common concern of all levels and sectors. However, in recent decades the Bang Giang - Ky Cung River has been subjected to the strong influence of socio-economic activities: mineral exploitation, domestic waste, industrial activities, increased use of chemical fertilizers, pesticides polluting water resources, affecting the lives of fish and aquatic species. Many species of economic value, rare species are rapidly reduced in the number of strains, reducing biodiversity. Therefore, research into biodiversity resources of fish species, assess the status of exploitation and adverse activities on fish resources, contributing to the development of scientific basis for proposing solutions to protect, use rational and sustainable development of fish resources of the system. The Bang Giang - Ky Cung river system is urgent. On that basis, contributing to the education and construction of animals in the country. Provide updated data, the latest species composition, distribution characteristics, the status of resources, species need conservation, so that local authorities refer to the development of biodiversity protection plan. In general, fish in particular contribute to the overall development of the locality. Stemming from the above reasons, I chose the project “Research on the fish fauna of the Bang Giang - Ky Cung river basin in Vietnam” 2. Objectives of the research Identification of species composition, ichthyofaunistic diversity of Bang Giang – Ky Cung river basin. Cataloguing of fish species according to types of populated aquatic ecosystems and habitats, distribution characteristics, determining the geographic distribution of Bang Giang - Ky Cung fishery. Investigation and assessment of the status of resources and fisheries in the study area. Proposing some measures to protect and exploit rational fish resources in the Bang Giang - Ky Cung river system, thus building the scientific basis for the sustainable use and development of fish resources. 3. Main research contents of the thesis Study on biodiversity composition of fish species in the Bang Giang - Ky Cung river system. Analysis of geographic distribution, distribution by aquatic ecology of fish species in the study area. Characteristics, properties zoogeography of the Cao Bang and Lang Son fish fauna for the freshwater fish fauna of Vietnam. 2 Assessment of the status of resources, demand for use, situation of exploitation of people in the study area, serving for the management, protect fish resources, measures for conservation of fish resources and development of fisheries resources in the Bang Giang - Ky Cung river system. CHAPTER 1. OVERVIEW 1.1. Freshwater fish study 1.1.1. History study of freshwater fish fauna of Vietnam 1.1.2. Brief history of the Bang Giang - Ky Cung river fish fauna The first research in Cao Bang - Lang Son fishery was Vailant E., (1891, 1904), collected and classified 6 species and described 4 new species in Lai Chau, recorded 5 fish species in Lang Son. Chevey P. (1930, 1932, 1936, 1937) studied the composition of freshwater fish species in northern Vietnam including the fish fauna. In 1978, in his book "The freshwater fishes of North Vietnam" Mai Dinh Yen recorded fish fauna Cao Bang - Lang Son has 56 species belonging to 13 families 47 genara 5 orders. Works "Freshwater fish of Vietnam" volume 1 of Nguyen Van Hao and Ngo Si Van (2001) and "Freshwater fish of Vietnam", Volume 2, Volume 3 of Nguyen Van Hao (2005), recorded 101 fish species belonging to 69 genera in Cao Bang - Lang Son belong to 18 families and 5 orders. In 2005, Nguyen Kiem Son conducted a survey on "fish fauna in Cao Bang province. The result found 54 fish species belonging to 42 genera, 15 families and 5 orders. In 2005, Ngo Sy Van, Pham Anh Tuan announced the fish fauna of two provinces Cao Bang - Lang Son has quite diverse species composition of 107 species of 74 varieties 22 families and 7 orders. In China, there are studies on the composition of fish species: fish fauna of the China Guangdong and Guangxi fish. The total number of species recorded in Guangxi province is 290 species of fish, of which Tay Giang river borders Vietnam receiving water from Bang Giang river - Ky Cung has recorded 125 species. In recent years, the Guangxi fish fauna has recorded new species of fish: Acrossocheilus malacopterus, Rectoris longibarbus and has recorded with distribution in Vietnam. Thien Quang Huynh and I-Shiung Chen (2013), announced Opsariichthys duchuunguyeni from the Bang Giang - Ky Cung River in Cao Bang - Lang Son province, northeastern Vietnam. Nguyen Van Hao, Vu Thi Hong Nguyen, Nguyen Thi Dieu Phuong (2015), describe three new fish species belonging to Silurus Linnaeus, 1758, (Siluridae, Siluriformes) found in northern provinces of Vietnam: Silurus caobangensis and Silurus langsonensis. As a result, there are 7 researches on the fish fauna of the Bang Giang - Ky Cung river basin. The results show that there are 172 species belonging to 93 genera, 23 families and 7 orders. 3 1.2. Overview of the natural and social characteristics of the study area 1.2.1. Natural features of the study area 1.2.1.1. Geographical location The Bang Giang - Ky Cung river system is located northeast of Vietnam in Cao Bang and Lang Son provinces. The area is 11,220 km2. 1.2.1.2. Morphological characteristics and topography The Bang Giang - Ky Cung river system is located in the lower part of the surrounding area, commonly known as the Cao - Lang low trough. Surrounding the northwest, west and southwest are the highest mountain ranges in the Northeast, with the highest peak being Pia Oac (1930 m). The Southeast is lowland with the highest peak is Mau Son peaks 1541 m, Ba Xa 1166 m. In the North Pole, the highest peaks are from 900 to over 1000 m. In terms of river basin morphology, the Bang River has higher elevation and basin slope than the Ky Cung River. The main river is also straight than the Ky Cung River, the average width of the basin is smaller than the Ky Cung River. However, the characteristics of the low trough is clearly shown 1.2.1.3. Climate characteristics The location of the Bang Giang - Ky Cung river basin is relatively hidden for the summer monsoon and directly welcomes the cold winter winds so it is dry and less rain, and the rainfall increases gradually from the Southeast to the Northwest. Also due to the location of hidden basins, deep in the continent that the rainfall caused by the storm is low; Lang Son is 246mm / year and Cao Bang is 140mm / year. Due to the strong influence of the winter wind and the obscurity of the sea, the rainfall is reduced in the region, the shortest rainy season in the North. 1.2.1.4. Hydrological regime Bang Giang river basin: The average density of rivers and streams in Cao Bang province is 0.5 - 1.0 km / km2. Flood season from June to September every year, peak flood in August, water volume in the flood season accounted for 70-80%. In contrast, the dry season lasts eight months, the water in the season accounts for 20 - 30%. Ky Cung river basin: The density of rivers and streams in Lang Son province is relatively high, the average density of rivers and streams is between 0.6 - 1.2 km / km2 compared to the average density of the whole country ( 0.6 km / km2). Divided into two seasons: The flood season is concentrated in June to September each year, the water volume this season accounts for 66 - 80% of the total water volume in the year. Dry season lasts for eight months, but water volume accounts for 20 - 34% of the annual flow. 1.2.2. Socio-economic characteristics Cao Bang: Natural land area of 6,700,26km2. The population in Cao Bang is 522.4 thousand people, with a population density of 79.08 people / km2, Cao Bang's economy is still underdeveloped. There are 28 ethnic groups in the province, 42.54% of which are Tay majority; Nung ethnic group accounts for 32.86%; Dao ethnic 4 group accounts for 9.63%; H'mong ethnic group accounted for 8.45%; Kinh majority accounts for 4.68%; The population of San Chay is 1.23%; Lo Lo group accounts for 0.39%; Hoa ethnic group accounts for 0.033%; Ngai ethnic group accounted for 0.013%; other ethnic groups account for 0.18%. The economic structure is mainly agricultural, while the area of cultivated land is limited, most of the crops are food and production is monoculture.