Tunisian reservoirs: diagnosis and biological potentialities

Due to scarcity, irregular rainfall and increasing water demand, several reservoirs have been built in recent decades in Tunisia to meet water needs for essential uses, which is generally done without analysis of their capacity to maintain a high quality of aquatic life and equitable distribution of water resources. Currently, 90% of available water resources are already mobilized and climate change exacerbates the country's aridity which makes it difficult to monitor water needs. With a view to contributing to their effective management and setting future directions for controlling and improving inland fish productivity, a comparative limnological study was carried out on 8 artificial reservoirs that were stocked with mullet fry. This study, based on a review of existing data, provides information on the availability and quality of inland water resources in relation to international standards and the biological potential (plankton, fish and other organisms) of these reservoirs. The satisfactory water quality for aquatic life, as well as the significant growth and production of introduced species associated with the rearing of mullet fry, clearly show that, despite several problems, Tunisian reservoirs represent an important potential that still needs to be developed. To this end, we recommend to improve the fishing techniques and the stocking of mullet fry. In addition, the strengthening of fishermen's groups, the encouragement of private initiative and the quality control of water and fish meat are highly requested.