Mekong River Commission

Recent developments in promoting the farming
of indigenous species

By Suchart Ingthamjitr *

The first of three articles on the region's booming aquaculture sector

The Mekong's fisheries are still productive, but the warning signs are clear. Although the size of the overall catch appears stable, the catch of some large, late-maturing species is declining and the average size of several other commercial species is getting smaller. These are the symptoms of approaching over-exploitation. In cooperation with the fisheries agencies of the four member countries, the MRC Fisheries Programme promotes management in the Lower Mekong Basin in ways that will preserve productivity. However, the demands of the basin's growing population mean that capture fisheries alone may not be able to guarantee food security in the long term. Aquaculture is a way to increase fish production and help meet growing demand while addressing the issues of food security and poverty alleviation.

Why indigenous species?
The main factors causing loss of biodiversity are habitat loss followed by alien species (Table 1 page 21). Indiscriminate introduction of alien species into the basin represents a serious threat to fisheries and can cause great economic and environmental damage. Invasive alien species can cause habitat alteration, increased competition and predation, and further losses through co-introduction of disease. Past extension of aquaculture techniques promoting alien species in the basin reflected a lack of knowledge of the biology and culture of indigenous species. The introduction of established alien species was expedient because seed production and culture systems could be extended rapidly and successfully without lengthy research and domestication processes.

Under its Aquaculture of Indigenous Mekong Fish Species (AIMS) component, the Fisheries Programme aims to develop economically-feasible aquaculture techniques for nine indigenous species to complement or replace the use of exotic species. This is being achieved though on-station and on-farm research into broodstock management, breeding, nursery and grow-out techniques for the selected species. This is being followed by the development of extension materials and packages. The immediate target group is government researchers working for aquaculture research and development institutions in the four countries. The development target groups are smallscale farmers.

Phase 2 of the component's operations focus on three main areas-propagation techniques, genetic information and stock enhancement. These three areas complement each other, and can support the activities of other components. For example, indigenous fish seed produced by the developed propagation techniques has been used not only for aquaculture but also for stock enhancement. Genetic information has been used for selective breeding programmes, appropriate stocking and the movement of indigenous fish. The information is also useful for modelling the impact of dams on fisheries. Altogether, outputs generated under these three areas significantly contribute to food security, poverty alleviation and fish biodiversity in the basin.

Table 1: Target species

English name	Scientific name	Khmer	Lao	Thai	Viet
Java barb	Barbonymus gonionotus	Trey chpin	Pa pak	Pla pak	Ca me vinh
Small-scale river carp	Cirrhinus microlepis	Trey pruol	Pa phon	Pla nuan chan	Ca duong
Mud carp	Cirrhinus molitorella	Trey phkar kor	Pa kaeng	Pla kaeng	Ca troi trang
Red tail catfish	Hemibagrus wyckioides	Trey khya	Pa kherng	Pla kung	Ca lang xanh
Hoeven's carp	Leptobarbus hoevenii	Trey prorlung	Pa poeng	Pla poeng	Ca long tong soi
Elephant ear gourami	Osphronemus exodon	Trey romeas	Pa ment	Pla rad	Ca tai tuong
Bocourt's catfish	Pangasius bocourti	Trey pra	Pa suay keo	Pla saa whai	Ca tra song
Sutchi river carp	Pangasianodon hypophthalmus	Trey pra kchau	Pa nyang	Pla yang	Ca ba sa
Krempf's catfish	Pangasius krempfi	Trey pra bong lao	Pa suay sor	Pla suay sor	Ca bong lao

 

Dr Suchart addressing the annual meeting of
the MRC Fisheries Programme in Sieam Reap
in June.    Photo: Lem Chamnap

Propagation techniques
About 1,100 species of fish live in the Mekong River (see page 4). These range from very small species to well-known large species such as the Mekong giant catfish (Pangasianodon gigas). Given this wide diversity, the AIMS Component has had to target its resources on species that are commercially important. The study of propagation techniques focuses on four main factors-broodstock management, breeding, nursing and grow-out. With the progress made so far, we can now produce seed of all nine target species by using captive and wild brood fish but with different levels of success for each species. To improve economic feasibility, issues that need to be further investigated include broodstock conditioning for maturation, breeding techniques to increase fertilisation and hatching rates, nursing techniques to increase survival and growth, and cost-effective culture techniques to increase production.

To support complementary research of existing techniques and avoid repeating or duplicating research efforts, information sharing and exchange is necessary for cooperation in regional aquaculture development. Sharing and exchanging information between researchers in the four countries is normal practice for the AIMS network. The component has, however, also cooperated with France's Agricultural Research Centre for International Development (CIRAD) in organising the "Participatory Research Training on Mekong Indigenous Fish Propagation" in Champasak in southern Lao PDR last year. The field activity aimed to share and exchange propagation information on four indigenous species-the small-scale river carp (Cirrhinus microlepis), Krempf's catfish (Pangasius krempfi), the red tail catfish (Hemibagrus wyckioides) and Jullien's carp (Probarbus jullieni)-among researchers of the four countries.

Table 2: Broodstock management

Species	Year	Status
Small-scale river carp Cirrhinus microlepis	2006	Complete
Sutchi river carp Pangasianodon hypophthalmus	2007	Complete
Krempf's catfish Pangasius krempfi	2007	Complete
Black shark minnow* Labeo chrysophekadion	2008	Analysis
Mud carp* Cirrhinus molitorella	2008	Analysis
Climbing perch Anabas testudineus	2009	Collection
Red tail catfish Hemibagrus wyckioides	2009	Collection

Genetic information
Domestication of broodstock is a prerequisite for aquaculture development and is part of the long-term strategy of the AIMS Component. Many indigenous fish species have been domesticated in captive conditions for broodstock in the four countries. Genetic investigation of these captive as well as wild stocks across the region aims to provide genetic information for proper broodstock management and orbreeding schemes. Good seed quality therefore supports aquaculture development. DNA analysis of both natural and hatchery populations of the Sutchi river catfish (Pangasianodon hypophthalmus) in the basin has indicated that the species is genetically separated into several sub-populations and that natural populations are at risk. Upgrading of hatchery broodstock quality and management plans are urgently required. Genetic information is also important for stock enhancement and the movement of fish. Movement of domesticated fingerlings of the smallscale river carp from Lao PDR to Cambodia in 2008 benefited from the use of genetic information. DNA testing showed that the populations of this species in the two countries were genetically identical. Similarly, stocks of Krempf’s catfish in Lao PDR, Cambodia and Viet Nam are the same genetically.

Genetic information is also a significant input into the model developed to assess the impact of dams on fisheries. Long-distance migratory fishes are likely to be the species most threatened by mainstream dam development. Genetic information tells us whether fish distributed along a stretch of the Mekong are from single or multiple stocks. Fish from single stocks are more susceptible than those from multiple stocks. Genetic information can therefore help fisheries managers mitigate the likely impacts of dams.

Stock enhancement
Fish stocking has been widely practiced in the basin but it is generally associated with ceremonies or raising awareness. Normally, only small numbers of fingerlings are released. In addition, there is no postassessment of the stocking exercise. As a result, it is Aquaculture (1) not known how well the stocking programmes succeed in terms of diversity and maintaining production.

Table 3: Stocking programme

Species	Year	Country
Mud carp Cirrhinus molitorella	2007	Lao PDR
Black shark minnow Labeo chrysophekadion	2007	Lao PDR
Hoeven's carp Leptobarbus hoevenii	2008	Cambodia
Java barb Barbonymus gonionotus	2008	Cambodia
Giant barb Catlocarpio siamensis	2009	Viet Nam

Stock enhancement initiated by the AIMS Component focuses on aspects of diversity and production. To monitor viability and growth of the stocked fish, post-stocking assessment is undertaken in conjunction with the either the Fisheries Ecology, Valuation and Mitigation Component of the Fisheries Programme or the Fisheries Management and Governance Component. Stocking of economicallyimportant species in Lao PDR and in Cambodia is a good example of aiming to increase production and raise incomes of the rural poor. Our stocking programme has also been extended to include diversity maintenance. Stocking of the giant barb (Catlocarpio siamensis) will be initiated this year in Viet Nam. The stocking programme will increase its role in conserving fish species vulnerable to water development projects. Many white fish such as the Mekong giant catfish, Jullien's barb and the giant barb can adapt well in closed water. Breeding and stocking of these species as well as many other species will be an opportunity to ensure their viability and sustainability, make the techniques already developed for indigenous fish species more complete and competitive while increasing incentives for smallscale farmers. However, the success of small-scale aquaculture of indigenous fishes requires government support to complement technical information. A training of trainers programme developed by the Southeast Asian Fisheries Development Center (SEAFDEC) is a good example of technology transfer from research institutions to the rural poor by extension officers. The project, entitled "Promotion of Community-based Aquaculture in Remote Rural Areas of Southeast Asia", is also an example of complementary activity in promoting aquaculture development in the region.

* Dr Suchart is the coordinator of the Aquaculture of Indigenous Mekong Fish Species (AIMS) component of the MRC Fisheries Programme. This article is based on a presentation he gave to the annual meeting of the programme in Siem Reap in June.