Biodiversity and Fisheries in the Mekong River basin

Relatively un-regulated tropical rivers support a high biodiversity, rivalling that of the most diverse marine systems. This is due, in part, to extreme ecosystem complexity. Such rivers traditionally support very important, but often under-valued, fisheries.

 

The fishery of the Mekong Basin is one of the most productive river fisheries in the world. High diversity of resources, in close proximity to large rural communities, leads to a high degree of participation in resource exploitation. Impressive large commercial fisheries occur in the basin, but because most people farm as well as fish, their involvement is largely part-time, using smaller fishing gears. The links between biodiversity and exploitation are immediately obvious. Reduced biodiversity will lead to decreased participation, loss of livelihoods and generally unfavourable socio-economic impacts.

 

Caution needs to be exercised when applying to river fisheries conclusions that have been drawn from marine fisheries. These function differently in several notable respects. Threats to biodiversity that arise from within the sector include over-exploitation and the use of destructive gears. However, the most severe threat to biodiversity in Mekong comes from outside the fishery, and result from activities which cause extensive loss of habitat, ecosystem simplification and reduced water quantity and quality.

 

Aquaculture should be managed to avoid impacts upon biodiversity. Chief amongst these are habitat loss due to conversion of wetlands into aquaculture operations, and the widespread introduction of exotic species and native strains/varieties that result in direct loss of genetic diversity. Effective remedies for the latter include the application of codes of practice for use in pre-introduction assessments.