On the incidental fishery of skates and rays off Calicut

Abstract

The total skates and rays landed as incidental components by the three main gears, trawl net, drift net and hooks-and-lines, accounted for 70.9 t, forming 10% of the total elasmobranch landings of Calicut during 1977-80. The most common species of rays were the sting rays, spotted eagle-ray, and the devil-ray, and the skate, R. djeddensis. The trawlers alone landed 95%. The trends of effort, catch and catch rate, examined for the 10-year period 1971-1980, showed that during the earlier half both catch and CPUE had a general upward trend, the former reaching the alltime high of 64 t in 1974 followed by the latter reaching the maximum of 11.9 kg per standard effort in 1975, after which both had descended down steadily to the alltime low of 1980, with clear negative response to effort, indicating the probability that the stock in the area could not stand the type of effort that was put in 1974-75. The reasons peculiar to this elasmobranch group contributing to its easy depletion are pointed out.