Dataset Information

Biodiversity of aquatic organisms in the Mekong Delta, Vietnam.

ABSTRACT:

Background

The Mekong River is the 10^th largest river in the world. It is recognised as the most productive river in Southeast Asia and economically essential to the region, with an estimated 60-65 million people living in the lower Mekong Basin. The Mekong Delta within Vietnam is considered a highly vulnerable ecosystem under threat from increasing anthropogenic pressure, such as dam construction and, as a consequence, the Delta is sinking and altering the natural hydrological cycle. Dams also lead to eutrophication and pollution of downstream water from regulated water flux and water stagnation. Another threat is climate change coupled with the lower rainfall, which could lead to an increased risk of drought in the Mekong Delta Basin. Thus, these project data represent an important baseline reference. The ecological health of the Mekong Delta's environment, as indicated by the quality and availability of its water and biological resources, largely determines the economic and social development of the region, which produces about half of the agriculture and aquaculture products of Vietnam.

New information

This paper reports quantitative data on the biodiversity of six groups of aquatic organisms: bottom and pelagic fish, macrozoobenthos, microorganisms, phyto- and zooplankton in the Mekong Delta within Vietnam, as well as data on the physicochemical parameters of water and bottom sediments. The data were collected during 2018-2022 as part of the Ecolan E-3.4 programme within the framework of the research plan of the Joint Russian-Vietnamese Tropical Research and Technological Center. All presented datasets are published for the first time.

SUBMITTER: Seleznev DG

PROVIDER: S-EPMC10848352 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature

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Publications

Biodiversity of aquatic organisms in the Mekong Delta, Vietnam.

Seleznev Dmitriy G DG Dinh Cu Nguyen CN Hai Truong Ba TB Karpova Evgeniia P EP Kim Chi Duong Thi DT Kosolapov Dmitriy B DB Kosolapova Natalya G NG Malin Mikhail I MI Malina Inga P IP Man Le Quang LQ Prokin Alexander A AA Prusova Irina Yu IY Sharov Andrey N AN Statkevich Svetlana V SV Tsvetkov Alexander I AI Udodenko Yuriy G YG Zakonnov Viktor V VV Zhdanova Svetlana M SM Krylov Alexander V AV Tiunov Alexei V AV

Biodiversity data journal 20231024

<h4>Background</h4>The Mekong River is the 10<sup>th</sup> largest river in the world. It is recognised as the most productive river in Southeast Asia and economically essential to the region, with an estimated 60-65 million people living in the lower Mekong Basin. The Mekong Delta within Vietnam is considered a highly vulnerable ecosystem under threat from increasing anthropogenic pressure, such as dam construction and, as a consequence, the Delta is sinking and altering the natural hydrologica ...[more]

PMID: 38327301

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Project description:The Mekong Delta in Vietnam has seen a rapid development and intensification of aquaculture in the last decades, with a corresponding widespread use of antibiotics. This study provides information on current antibiotic use in freshwater aquaculture, as well as on resulting antibiotic concentrations in the aquatic environment of the Mekong Delta. Two major production steps, fish hatcheries and mature fish cultivation, were surveyed (50 fish farm interviews) for antibiotic use. Different water sources, including surface water, groundwater and piped water (164 water samples) were systematically screened for antibiotic residues. To better understand antibiotic fate under tropical conditions, the dissipation behavior of selected antibiotics in the aquatic environment was investigated for the first time in mesocosm experiments. None of the investigated antibiotics were detected in groundwater and piped water samples. Surface water, which is still often used for drinking and domestic purposes by local populations, contained median concentrations of 21 ng L-1 sulfamethoxazole (SMX), 4 ng L-1 sulfadiazine (SDZ), 17 ng L-1 trimethoprim (TRIM), and 12 ng L-1 enrofloxacin (ENRO). These concentrations were lower than the predicted no effect concentrations (PNECs) and minimum inhibitory concentrations (MICs), suggesting limited antibiotic-related risk to aquatic ecosystems in the monitored systems. The dissipation half-lives of the studied antibiotics ranged from <1 to 44 days, depending on the availability of sunlight and sediment. Among the studied antibiotics TRIM was the most persistent in water systems. TRIM was not susceptible to photodegradation, while the dissipation of ENRO and SDZ was influenced by photolysis. The recorded dissipation models gave good predictions of the occurrence and concentrations of TRIM, ENRO and SDZ in surface water. In summary, the currently measured concentrations of the investigated antibiotics are unlikely to cause immediate risks to the aquatic environment, yet the persistence of these antibiotics is of concern and might lead to chronic exposure of aquatic organisms as well as humans.

Project description:Small-scale farming of meat chicken flocks using local native breeds contributes to the economy of many rural livelihoods in Vietnam and many other low- and middle-income countries (LMICs). These systems are also the target of high levels of antimicrobial use (AMU); however, little is known about the profitability and sustainability of such systems. Since small-scale farms are commercial enterprises, this knowledge is essential to develop successful strategies to curb excessive AMU. Using longitudinal data from 203 small-scale (100-2,000 heads) native chicken flocks raised in 102 randomly selected farms in Dong Thap province (Mekong Delta, Vietnam), we investigated the financial and economic parameters of such systems and the main constraints to their sustainability. Feed accounted for the largest financial cost (flock median 49.5 % [Inter-quartile range (IQR) 41.5-61.8 %]) of total costs, followed by day-old-chicks (DOCs) (median 30.3 % [IQR 23.2-38.4 %]), non-antimicrobial health-supporting products (median 7.1 % [IQR 4.7-10.5 %]), vaccines (median 3.1 % [IQR 2.2-4.8 %]), equipment (median 1.9 % [IQR 0.0-4.9 %]) and antimicrobials (median 1.9 % [IQR 0.7-3.6 %]). Excluding labor costs, farmers achieved a positive return on investment (ROI) from 120 (59.1 %) flocks, the remainder generating a loss (median ROI 124 % [IQR 36-206 %]). Higher ROI was associated with higher flock size and low mortality. There was no statistical association between use of medicated feed and flock mortality or chicken bodyweight. The median daily income per person dedicated to raising chickens was 202,100 VND, lower than alternative rural labor activities in the Mekong Delta. In a large proportion of farms (33.4 %), farmers decided to stop raising chickens after completing one cycle. Farmers who dropped off chicken production purchased more expensive feed (in 1000 VND per kg): 11.1 [10.6-11.5] vs. 10.8 [10.4-11.3] for farms that continued production (p = 0.039), and experienced higher chicken mortality (28.5 % [12.0-79.0 %] vs. 16 [7.5-33.0 %]; p = 0.004). The rapid turnover of farmers raising chickens in such systems represents a challenge to the uptake of messages on appropriate AMU and chicken health. To ensure sustainability of small-scale commercial systems, advisory services need to be available to farmers as they initiate new flocks, and support them in the early stages to help overcome their limited experience and skills. This targeted approach would support profitability whilst reducing risk of emergence of AMR and infectious disease from these systems.

Dataset Information

Biodiversity of aquatic organisms in the Mekong Delta, Vietnam.

Background

New information

Publications

Biodiversity of aquatic organisms in the Mekong Delta, Vietnam.

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