Nutritional composition of aquatic species in Laotian rice field ecosystems : possible impact of reduced biodiversity

Abstract

The population density of Laos PDR has increased from 15 persons per square km in 1985 to 19 persons in 1995 and to 24 persons in 2005. This has threatened food security, which in Laos PDR is generally synonymous with rice availability. Rice production in Laos rose by 70 percent from 1990 to 2004. Evidence from Vietnam, Malaysia and Central Thailand has shown that the rise of rice production steadily decreases the population of aquatic animals in rice field ecosystems, as a result of higher applications of fertilizers and pesticides. In Laos PDR, the use of fertilizers and pesticides is still minimal, but said to be increasing.

The role of aquatic rice field species in rural Laotian diets has been underestimated. Almost 200 species are consumed across the country. These aquatic animals potentially supply most of the vitamins A and B, calcium, iron, sulphur, essential fatty acids and amino acids that are needed by the villagers. However, national and regional food composition data bases contain very limited info on nutritional composition of these species. These aquatic animals are not consumed in large quantities elsewhere.

Field sampling was undertaken in Champasak and Savannakhet provinces for nine species of aquatic animals, including fish, amphibians, crustaceans, molluscs and insects. Additionally four samples of fermented fish sauce were included. The samples were transferred to the University of Tromso for detailed analysis.

The objective of the study was to gain knowledge on the nutritional composition of the most significant species included in the diet in Laos areas. As other studies have made estimates of the quantities consumed, the results of this work enable an assessment for the nutritional contribution of aquatic animals to the diet. The work also discusses the impact on nutrition of a possible decrease in the available species biodiversity.

This study documented that the aquatic animals that are consumed daily contained high amounts of protein, amino acids, calcium, iron and zinc. On the contrary, they contained a low amount of fat, fatty acids, and vitamin A. Amino acids, iron and zinc are important nutrients for the Laotians. As the food supply of rural households in rice farming areas of Laos is critically dependent on the environment, the sustainable existence of the rice-based aquatic animals is crucial factor to the nutritional status of the Laotians.

The objective of biodiversity conservation overlaps local and nutritional needs and should be emphasised in development of national nutrition policies, as well as agricultural development policies and fisheries management practices. Fishery managers and policy makers should integrate pro-poor community-based biodiversity conservation into their ongoing development programmes.