Efficiency of the main fishing gears used in prawn fishery in the Jaffna lagoon

The main gears used in prawn fishery in the Jaffna Lagoon are 'sirahu valai', drag net, hoop net and 'kandi'. 'Sirahu valai' collects the largest prawns and is less efficient with an average CPUE of 3.70 Kg. gear^-1 day^-1 and more expensive than the other gears. 'Kandi', the cheapest of the gears is operated only at a few locations in the lagoon and is being abandoned due to its poor efficency (CPUE of 1.88 Kg. gear^-1 day^-1). The drag net with an average CPUE of 6.12 Kg. gear^-1 day^-1 is the most efficient gear. However, this gear collects the smallest prawns especially Metapenaeus monoceros and Penaeus emisulcatus, during the months of May and October. January was the most productive month as far as the fishery in Jaffna lagoon was concerned. The year 1987 with an annual average CPUE of 4.04 Kg. gear^-1 day^-1 was more productive than 1986 with an average CPUE of 3.77 Kg. gear^-1 day^-1. Considering the average total length of prawns caught in the different gears and their CPUE during 1986 and 1987, a total ban or at least a restriction on the use of drag net during the months of May and October in the Jaffna lagoon is recommended.