Lagoons in the East Coast; are They Potential Sites to Develop Fisheries in Sri Lanka

Abstract

Lagoons are highly productive ecosystems which provide habitats and nursery grounds formany fish species and contribute to fisheries productions of a country. The status of fisheryin lagoons in the East coast has not been assessed in the past due to civil unrest in thecountry. This study was conducted in two lagoons in Ampara Distrcict; Panama and Pottuvil.The status of fishery was assesed over a six month period using data obtained from the dailycatch brought to the landing centres. Thirty five species of food fish, four species of shrimpsand the mangrove crab, Scylla serrata are harvested from the lagoons using different fishingmethods. The bulk of the food fish caught (63%) in the Panama lagoon were represented bySiganas lineatus, Oreochromis niloticus, Mugil cephalus, Gerres argyreus and Mystus guiliowhile only Oreochromis niloticus and Mugil cephalus contributed to a high percentage (59%)in the Pottuvil lagoon. The total productions of the Panama and Pottuvil lagoons wereestimated to be 74.05 kg/ha/yr and 67.48 kg/ha/yr respectively. The productivity is high inboth the lagoons compared to the average annual productivity of a Sri Lankan lagoon whichis about 22 kg/ha/yr. However, in comparison to the extent of the two lagoons (Panama 73haand Pottuvil 270ha), productivity of the Panama lagoon is significantly higher than that of thePottuvil lagoon (P=0.01) which makes Panama a potential site to develop lagoon fisheries inthe east coast. The extent of the mangrove vegetation (Panama 83ha and Pottuvil 46.6ha)with respect to the total surface area of the lagoons is a possible reason for the productivitydifference of the two lagoons. Both the lagoons show seasonal fluctuations due to rainfall andsalinity changes according to the Canonical Correspondence analysis that was performed andfish migration patterns have been observed in these lagoons. The life styles of the localpeople are highly dependent on lagoon fisheries in these areas thus; the environmental stressis higher on the ecosystem. Non regulation of net mesh sizes, destruction of mangroves,illegal land use and use of motor boats have caused certain environmental issues hence,suitable management practices should be introduced to ensure the sustainability of the lagoonecosystem.