A rationale for introducing a subsidiary fishery in tropical reservoirs and lakes to augment inland fish production: case study from Sri Lanka

An extra 30–40 million tonnes of food fish will be required by 2050 to meet the increasing need for a growing population. In the wake of plateauing of the traditional food fish supplies from marine capture fisheries, the gap in the supplies will have to be met from aquaculture and other plausible strategies, including increased inland fish production. The existing fisheries in tropical reservoirs and lakes traditionally tend to target only table-sized fish, often exotics and/or translocated species, using a single type of gear, mostly gill nets. In such fisheries, many small indigenous species (SIS) are unexploited due to the prohibition of the use of suitable fishing gear. The status of fisheries for small, indigenous species of four Sri Lankan reservoirs was investigated with a view to identifying regulatory constraints to the establishment of SIS fisheries without adversely impacting existing commercial fisheries. It is estimated that a potential of 7.5 t per fisher per annum of SIS through the introduction of a new fishery is obtainable. This study is significant as SIS are recognized as important sources of essential macro- and micronutrients which can play a crucial role in combating malnutrition and micronutrient deficiencies in rural populations of many South and Southeast Asian countries.