Analysing the agrarian reservoir environment to optimise culture-based fisheries in Sri Lanka

Abstract

Compared to the long agrarian history of Sri Lanka, inland fisheries in agrarian reservoirs are a recent development based mainly on introductions of exotic species. The aim of this short review is to analyse published information on agrarian reservoir environment and its suitability for fisheries production. In global scale, total fisheries production keeps rising due to both marine and inland aquaculture inputs, and a similar trend can be found in Sri Lanka as well. The development of culture-based fisheries (CBF) in agrarian reservoirs was not efficient at first, due to lack of knowledge on the limnological properties of the reservoirs. Since then, several scientists have formulated relationships between fish yield and the reservoir nutrient levels and other factors deciding primary production. Lately, indigenous riverine giant freshwater prawns (GFP) were introduced to the reservoir systems as a culturable species to diversify the catch and boost the income of rural fishing communities. Despite the continued stocking, the catch of GFP in return was not comparable. As a solution, proper scientific investigations on harvesting techniques, assessment of existing biomass, GFP distribution in microhabitats and their interactions with the agrarian reservoir environment and co-existing species, were subject to research.