Culture-based and capture fisheries development and management in reservoirs in Vietnam

• University of Agriculture and Forestry, Vietnam
• Department of Agriculture & Rural Industries, Fisheries Division, Vietnam
• Victorian Marine and Freshwater Research Institute, Australia
• Research Institute for Aquaculture No. 3, Vietnam
• Department of Agriculture & Rural Industries, Fisheries Division, Vietnam
• Research Institute for Aquaculture No. 1, Vietnam

Vietnam's reservoirs are a source of livelihood for many people living around them, and often these communities include displaced people and ethnic groups who tend to be the poorer sectors of the community. Two types of fishery are involved: culture-based fishery in small, farmer-managed reservoirs and capture fishery in medium and large reservoirs. The average level of production from Vietnam's reservoir fisheries is among the lowest in Asia, suggesting that their potential is not being realised. Thus, fishery research and development is a priority for the Vietnam Government. This project built on the recommendations of an initial study that recognised potential to develop a culture-based fishery in small reservoirs, also that rearing fry to fingerling stage in perennial reservoirs could help to meet seed stock requirements.
In Australia, public waters such as areas of the Murray-Darling Basin have the potential to be used for fisheries and aquaculture. The researchers sought to develop a better scientific basis and policy or planning framework for such enterprises.

The main aim of this project was to increase the availability and affordability of fish to the rural poor and to generate livelihood opportunities for communities living near reservoirs, by providing the Vietnam Government with relevant information and advice on how to significantly improve the fish yield from reservoirs.

For culture-based fishery, the project team developed a best-practice model through trials on 20 reservoirs. The team studied the effects of species combinations, stocking density, staggered harvesting (which could overcome the problem of oversupply during a short period) and use of manures to increase productivity, and also undertook a cost-benefit analysis.
For the capture fishery, project workers studied the limnology (e.g. pH and conductivity) and the nature and extent of the fishery in terms of such factors as species composition, regulations on landing size, marketing and management strategies and socioeconomic conditions of fishers. The team collated historical and current data from 14 representative reservoirs in Vietnam to develop preliminary guidelines for sustainable use of fisheries resources. Models linking patterns of land use with yield (developed for use in Sri Lanka) were seen to have potential application for Vietnam, and the project looked at using such models to improve management of individual reservoirs.
The project team trained fishery managers in sustainable use of inland fishery resources and integrated catchment management. Other training introduced modelling and GIS techniques. The team fostered introduction of resource management of inland waters into the tertiary curriculum.
In Australia, the researchers began to develop the scientific basis and policy or planning framework needed to encourage use of public water storages in the Murray-Darling Basin for commercial cage culture.

Overall, both components of the projects viz. on fisheries management in large reservoirs and culture-based fisheries development in small farmer managed reservoirs were successfully completed, on time and on budget. Apart from the achievements of each of these components, the most significant outcome, to which the project was very much responsible, was a policy adoption by the Government of Vietnam, which includes the incorporation of reservoir fisheries as a strategy to increase fish food production and increase income levels of fishers and farmers through fishery related activities in reservoirs in Vietnam, and also initiate funding of R&D projects on reservoir fisheries. Accordingly, the current 10-year plan for fisheries targets to increase reservoir fisheries production to 250,000 t by 2010, from about 20,000 t currently.

In addition, the project enhanced the research capacity in a key research institution in Vietnam, Research Institute for Aquaculture No. 1, and contributed to the development of a critical mass of researchers on reservoir fisheries, and a dedicated unit thereof in the Institute. The project also increased the dialogue between researchers and farmers, as well as with provincial authorities responsible for development fishery activities, which will contribute to the facilitation of further R & D activities that will impact on reservoir fish production.

Culture-based fisheries in small reservoirs: The research component pertaining to culture-based fisheries was completed successfully in May-June 2005. Based on trials, over two growth cycles, each of 9-10 months duration on 32 water bodies in two provinces in North Vietnam (ThaiNguyen and YenBai) and one in the Central Highland region (DakLak), and in combination with data gathered from a previous small project (FIS/97/68), the criteria that would optimise fish production in farmer-managed small reservoirs were determined. Thus knowledge is now available on best practice approach to culture based fisheries in Vietnam, encompassing the best species combination and ratio, the stocking density and the optimal size at stocking to be utilised for reservoirs in different climatic regions, and in relation to relatively easily measurable water quality characteristics, such as conductivity and chlorophyll a content. As well, the optimal harvesting strategies and marketing chains needed to ensure that farmers obtain the maximum returns have been recommended/developed.

Most of all the findings have been extended, successfully, to other provinces in north Vietnam, through a series of workshops aimed at the potential farming communities. These workshops have established a useful conduit between the researchers and farmers and provincial fishery authorities, and facilitated the uptake of culture-based fishery activities in new areas. In addition, the Provincial Governments of at least two provinces (ThaiNguyen and YenBai), have incorporated culture-based fisheries development as a strategy to increase the income of rural farming communities and contribute to poverty alleviation.

Fisheries management in large reservoirs: A total of 14 large reservoirs, located in the different climatic regions of the country were involved in the study. Where available, historical data on individual fisheries were obtained and supplemented with in situ data collection over the period 2003 to 2005., It was evident that the management regimes had changed significantly with economic rationalisation in the early to mid-1990s, and consequently, all subsidies provided by the government had been withdrawn, and the fisheries of the large reservoirs went into a period of disarray. Currently, the reservoir management regimes differ from reservoir to reservoir, and range from complete private management, when water bodies are leased out to fishery agencies through a bidding process, to a system of co-management that involves fishers and a government "backed" fishery agency.

The data obtained suggest that in reservoirs exceeding 700 ha, stocking is not a cost-effective strategy to enhance fish production, and in reservoirs less than 700 ha the stocked species recruit to the fishery, most effectively, two years post-stocking. Based on the data, statistical models were generated showing stocking to yield relationships, which could be used by fishery managers. Detailed studies were conducted on the fishery of two reservoirs (ThacBa and NuiCoc) that included fish faunal composition, gear efficiency, catch curves, catch per unit effort to yield relationships. Based on all this information specific recommendations for each reservoir group, were developed.

The biology and the fishery of the artisanal fishery on the shrimp, Macrobrachium nipponensis, little known in Vietnamese waters but which supports the livelihood for a significant number of fishers, living in the vicinity of the reservoirs, was addressed. Based on the available data maximum catch limits and fishing pressure were determined, and this information is expected to help sustain this fishery in the long term. In view of the increasing concerns on impacts of dam-building on biodiversity the study attempted to discern relationship of fish species diversity in relation to a number of reservoir features (size, age, mean depth, shoreline length), including catchment features such as land-use patterns and human population density. Interestingly, the reservoir fish species diversity was significantly and positively correlated to the catchment human population density. Overall, and apart from the specific management measures that have arisen from the study, the project has developed an appreciation, amongst provincial authorities and fishery agencies, of the need for a science-based management strategy on reservoir fisheries to ensure long-term sustainability and optimise the outcomes for human benefit.