Mekong River Commission

Introduction

The year ending (2005) is the last full year of the first phase of the MRC Fisheries Programme; phase two will begin in January 2006. Now is therefore an opportune time to review the status of the Mekong fisheries, their health and their place in the development of the natural resources of the lower Mekong basin. This review also provides a background to the objectives and activities of the next phase of the Programme.

The Size and Economic Value of the Fishery

The Mekong's fisheries are an integral and vital part of the socio-economic structure of the countries in the lower Mekong basin: Cambodia, Lao PDR, Thailand and Viet Nam. Most of the 60 million people living in the basin are in some way involved in the fisheries sector; fish and aquatic animals are an essential component of their diets and provide an important source of hard income for many poor rural households.

Our latest assessments suggest that total annual catch of fish and other aquatic products exceeds three million tonnes (see box opposite). Nearly 80% of the catch comes from river fisheries with reservoir fisheries and aquaculture contributing around 10% each.

The total value of the fisheries is about US$2,000 million. This estimate certainly understates the macro-economic significance of the fisheries sector because it does not include the incremental value derived from resale, exports or associated industries. Even so, the fisheries make significant contributions to the economies of all four riparian countries.

The fishery sector accounts for nearly 12% of Cambodia's GDP and contributes more to the country's economy than does rice production. The value of the catch in Lao PDR is equivalent to 7% of that country's GDP. Although they are proportionally less important, the Mekong fisheries sector in Thailand and Viet Nam still add well over US$750 million to the economies of each country.

At present, the fisheries seem to be in relatively good condition; the overall tonnage of the catch appears to be stable. However, the composition of the catch is changing. The proportion of some large, latematuring, fish is declining and the average size of several commercially important species is getting smaller. In addition more fishing effort is now required to catch the same quantity of fish. These are symptoms of approaching overexploitation. The root causes are few alternative employment opportunities for rural people, and the availability of cheap and highly effective fishing gears.

In addition to overexploitation, fish stocks are also are increasingly at risk from loss of natural habitat, barriers to migration and changes to the natural flood pulse of the river.

The Environmental Health of the Mekong

The health of the fisheries and the environmental health of the Mekong are closely related. Natural selection has finely tuned the reproductive cycle of most migratory fish to take maximum advantage of the ecological benefits provided by the seasonal inundation of the river's floodplains. Changes to the river's hydrology and water quality will disrupt the life cycle of many fish species with knock-on implications for the productivity of the fisheries.

At present, the Mekong is healthy. The river's annual flow is regular and its waters are largely free from industrial and agricultural pollutants. However, it is becoming clear that the seasonal flow of the river and aspects of its water quality are changing.

There is strong evidence from hydrological records going back over many decades that the amplitude of the Mekong's seasonal flood-recession cycle is gradually, but progressively, getting smaller. While the amount of water the Mekong discharges annually has remained remarkably consistent, the height and duration of the annual flood has attenuated and the flow during the dry season has increased. At the same time the sediment load carried by the river has fallen. As there have been no climatic changes during this period that could have produced these effects, it is likely they are the result of human interventions especially water management developments.

Destruction of habitat is the principal reason for falling biodiversity across the basin. In particular, the widespread conversion of forested floodplains to rice paddy has reduced the area of wetlands. Many migratory fish use these as habitats for spawning, rearing and feeding.

Records of fishery catches over the same period are incomplete and inaccurate and therefore we cannot assess precisely the impact these ecological changes have had on fish populations. At a local scale however, the intervention of human activity in the environment is well documented. This can take many forms. Dams and weirs can impede the passage of migratory fish cutting them off from spawning and feeding sites, flood mitigation schemes may prevent floodwater from inundating wetlands, clearing waterways to improve navigation may remove precious habitat in the mainstream channels.

While these interventions can cause serious damage to local fish populations, their impact may also spread far afield, and can impinge on the fisheries of neighbouring countries. These 'trans-boundary' effects are another facet of the complex interrelationship between the users of the Mekong, its waters and the fisheries they support; the river and its fish do not recognise international borders.

Looking Forward

We do not know if, or for how long, fish stocks can absorb current levels of exploitation and habitat degradation before the damage to them becomes irreparable. Furthermore, the stress on fisheries will increase as the population of the basin grows. Sustaining fish stocks that can support current and future demands requires careful and innovative fisheries management at all levels from local communities to national government. It also requires enhanced techniques to improve the aquaculture of indigenous Mekong fish species for consumption and to stock the river, reservoirs and lakes.

Further pressure on wild fish stocks will also come from increasing exploitation of the Mekong's natural resources by other development sectors. But these developments must proceed, if we are to tackle poverty and underemployment in the basin. The difficulty arises in balancing social benefits and costs to the environment in a way that ensures development of water resources is socially just and environmentally acceptable. It must be to the maximum benefit the people of the Mekong basin, especially the rural poor.

The Next Phase of the MRC Fisheries Programme

These then are the challenges that today face the Mekong's fisheries - pressure from overexploitation and competing demands for the river's water resources. We have designed the objectives and activities planned for the second phase of the Fisheries Programme around three distinct, but linked, facets of these challenges.

The first is the need to develop our knowledge of the biology of commercial species, as well as the ecological factors that underlie fish production. We must also determine the economic and social value of the fisheries, in order to achieve fair comparison with other development sectors. This is a prerequisite in planning basinwide water resource developments. The Capture Fisheries Ecology, Valuation and Mitigation Component (FEVM) will undertake this work.

Effective governance and fisheries management at all levels is essential to ensure use of the resource is equitable and socially just. The role of the Fisheries Management and Governance Component (FMG) is to support existing local and national fisheries bodies design and implement suitable and practical, management measures.

Exotic species are common in aquaculture operations in the Mekong, as fish farmers tend to utilise species for which the production techniques are well known. Exotic fishes that escape from aquaculture farms can compete strongly with indigenous species, often replacing them in their natural habitats. This can cause great damage to wild stocks. The activities of the Aquaculture of Indigenous Mekong Fish Species Component (AIMS-2) aim to improve culture technology of indigenous species with the objective of reducing the demand for exotic species for use in aquaculture.

In addition to the roles of these 'field-based' components, the Fisheries Programme also carries the responsibility to communicate information on fisheries to users, national fisheries agencies, to MRC's other programmes and its managers and to anyone else with an interest or stake in the Mekong's fisheries. This is one of the principal roles of the Programme Management and Communication Component (PMC).

The combined efforts of the four components have one objective, 'sustainable and coordinated development, utilisation, management and conservation of the fisheries of the Mekong basin'.