Sharks, rays and skates as a potential fishery resource off the east coast of India

The sharks, rays and skates form one of the important commercial fisheries of India, the average annual landings for 10 years (1958-67) being 33,442 m. tons. Of this, 15,537 m. tons are landed along the east coast and 17,605 m.tons along the west coast and the rest at Andaman and Nicobar and Laccadive groups of islands. Reports indicate that the Indian Ocean offers valuable fishing grounds for these fishes, especially for the larger varieties which can substantially augment the supplies of food, liver-oils, fins and shagreen. Along the east coast, good fishery for elasmobranchs exists along the coasts of Orissa, Andhra Pradesh, Madras State and in Andaman Islands. These fishes are caught almost round the year, the sharks on hook and line and in drift gill nets at depths varying from 16 to 100 metres and majority of rays and skates in trawl nets, drift and bottom set gill nets and shore seines at depths ranging from 4 to 100 metres. The common species of sharks include the blacktip-finned sharks of the genus Carcharhinus, species of Scoliodon, the hammer-head sharks, Sphyrna spp., the tiger-shark, Galeocerdo cuvieri and the zebra shark, Stegostoma fasciatum. The whale shark, Rhincodon typus, is occasionally landed. Rays of commercial importance are the cownose ray, Rhinoptera javanica shoals of which make frequent incursions into coastal waters of Gulf of Mannar, the butterfly ray, Gymmura poecilura, Himantura spp., Amphotistius zugei, Pastinachus sephen and the devil ray, Mobula diabolus. The common skates include Rhynchobatus djiddensis and Rhinobatus granulatiis and the saw-fishes of the genus Pristis. From the present trend, it would appear that the catches of elasmobranchs off the east coast could be substantially increased by extending fishing operations to deeper waters especially in the Gulf of Mannar and by the use of stronger nets from mechanised vessels. Fruitful results may also be expected along the east coast, including Andaman Islands by exploratory surveys to chart potentially rich grounds for these fishes