Coastal Aquaculture and Mariculture

Unit 7- Molluscan resources

7.1.4. Conservation and management
Conservation measures for chank should include (i) Intensive exploitation of chank should be avoided during the peak breeding season (Jan-Mar) every year for conservation of the egg capsules and baby chanks (2) The size at first capture needs to be increased from the present level of 64 mm to 75 mm MSD to enable the chanks to spawn at least once in their life and to avoid recruitment over fishing (3) The fishing effort should be decreased by about 35 % from the present level of exploitation (4) Laws should be enforced to prevent the discharge of industrial effluents and operation of mini trawlers over chank beds and (5) Declaration of protected areas, development of captive breeding technique and promotion of sea ranching.
Recently, the following species of gastropods have been included in the Schedule I of the Indian Wildlife (Protection) Act, 1972. The species are Cassis corn uta, charonia triton is triton is, Conus milne-edwardsi, Cypraecassis rufi1, Nautilus pompilius, Cypraea limacine, C. mappa, C. talpa, Fasciolaria trapezium, Harpulina arausiaca, L.chiragra chiragra, L.chiragra arthritica, L. crocata, L. millepeda, L. scorpius, L. truncata, Strombus plicatus slibbaldi, Trochus niloticus and Turbo marmoratus. The landings of the Turbo shells in Andamans also have very much come down when compared to few decades ago mostly due to overexploitation irrespective of the size of the animal. Hence, the stock of this gastropod is to be replenished urgently. This can be achieved by breeding and rearing them under controlled conditions for sea ranching. At present, there is no special hatchery for the gastropods or even a programme for their breeding and sea ranching. Nowadays the smaller gastropods like Cypraea are also overexploited which is evident from the decline in the availability of these shells. Regulation on size of the Cypraea exploited (above 5 mm) and a ban on gathering shell at least for three months once in a year during their breeding season need to be implemented.