- The expedition program was quite intensive. During two weeks, for 6–8 hours daily, starting early morning, we conducted ichthyological surveys on the Mekong River. We were mostly interested in the most common and abundant fishes of the Mekong Delta, including endemic species. The local fauna was represented, e.g., by the blackhand paradise fish, various catfish, anchovies, and righteye flounders. Working in tropical conditions was challenging not only because of high air temperatures but also because of sudden gusts of wind and strong tidal surges from the sea, - said Viktor Voronin.
Researcher of the Ecological Biochemistry Laboratory IB KarRC RAS Viktor Voronin and Senior Researcher of the Laboratory of Fish and Aquatic Invertebrates Ecology IB KarRC RAS Dmitry Bityutsky
The expedition itself was part of the international project "Mekong River Ecosystem under Global Climate Change and Human Impact", supervised by the Intergovernmental Coordinating Committee for the Russian-Vietnamese Tropical Centre. The project leader on the Russian side is RAS Corresponding Fellow Alexey Tiunov.
- The fieldwork was conducted in three sections of the Mekong River, covering the Vietnamese provinces of An Giang, Can Tho, and Soc Trang. The vessels for the ichthyological surveys were somewhat unusual for us – we worked from local fishing boats. Although these boats are rather small and difficult to operate in poor weather, we performed over 40 bottom trawlings at depths ranging from 2 to 30 meters. In total, during the expedition period, we collected about 400 biological samples for subsequent biochemical and molecular genetic analysis, – specified Dmitry Bityutsky.
Surveying the Mekong River Delta
The tasks for this expedition were to perform an ichthyological survey, collect biological material for further ecological-biochemical and molecular-genetic research, as well as assess the abiotic environmental factors in the fishing areas.
- This expedition is the first in a series to follow within the five-year project. Our colleagues have collected extensive biological material to start off with large-scale research. This includes studying and selecting metabolic biochemical indicators to be added to the comprehensive system for integrated assessment and monitoring of living systems and biological resources of freshwater ecosystems, particularly tropical aquatic ecosystems, through the case study of the Mekong Delta. The work will employ an advanced 'omics'/metabolic approach for comprehensive assessment of the effect of environmental factors and for identifying indicators of the state of organisms. This approach is based on studying low-molecular-weight organic compounds – metabolites, both intermediate and end products of metabolism – in bodily fluids and tissues, which will allow for determining the tolerance of compensatory reactions, the resilience and sensitivity of the studied species. The topic we are proposing has been relatively little studied in Vietnam or by Vietnamese specialists. Such studies have primarily dealt with aquaculture. Previously, we have collaborated with specialists from the A.N. Severtsov Institute of Ecology and Evolution RAS (Moscow) to study the role of lipids in the biology and reproduction of the sea urchin Diadema setosum in Nha Trang Bay, including obtaining applied data – determining the potential practical significance of lipid extracts from the sea urchin in terms of antimicrobial activity. We have previously done a similar microbiological screening for northern aquatic organisms of the White Sea. In the current effort, we also plan to obtain information on the bio-resource potential of aquatic organisms in the Mekong Delta based on specific biochemical parameters that have practical implications and are important when planning the sectoral potential and applications in biotechnology, aquaculture, and the food industry, – explained Svetlana Murzina, Head of the Ecological Biochemistry Laboratory at IB KarRC RAS.
In 2021–2022, Svetlana Murzina and Viktor Voronin participated in a Russian expedition to the shores of Antarctica aboard the research vessel Akademik Mstislav Keldysh, during which they specialized in studying lipids and fatty acids in marine organisms inhabiting Antarctic waters.
