1971

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    Indias Foreign Exchange Earners
    (Society of Fisheries Technologists (India) Cochin, 1971) T.K., Govindhan
    India's export earnings from fishery products have touched an all time record of Rs. 33.07 crores in 1969. The most important items which have contributed to this are processed prawn products, frozen lobster tails and frozen froglegs. Even though frogs are not of marine origin, they are processed and exported along with marine products so that for all practical purposes they are reckoned as seafoods. The following is an exhaustive list of the different species of prawns, lobsters and frogs that are found in our country, together with vernacular names wherever available, parts of India where they occur and the largest size (length) to which they grow. The different genera have been arranged in the order of their commercial importance and not according to any scientific principles. The main source of these informations is Bulletin no 14 of the Central Marine Fisheries Research Institute entitled "Prawn Fisheries of India," issued in August 1969, which may be consulted for further details regarding taxonomy etc.
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    Studies On Threshold Current Densities For Convulsion Of Fish Using A Square Wave Stimulator
    (Society of Fisheries Technologists (India) Cochin, 1971) Biswas, K.P.
    The threshold current densities and volltage tensions (body voltages) between the head and tail for bringing about distinct reactions in Salmo irideus, Cyprinus Carpio, Tinea tinea, Gasterosteus aculeatus and Salmo fario were studied. In C. carpio and T. tinea, absolute current densities required decreased with increase in length of fish. Threshold current densities for different reactions of fish increased with rise in water temperature and conductivity of surrounding medium except in case of T. tinea where low current densities were sufficient in higher conductivity of water. Impulse D. C. was superior to continuous D. C. Better effect was noticed in fishes in lower current densities when their bodies were parallel to the lines of current conduction.
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    On The Behavior Of Marine Crustaceans In An Electrical Field Of Alternating Current
    (Society of Fisheries Technologists (India) Cochin, 1971) Biswas, K. P.
    The minimum flow of current essential to produce electronarQ cosis and fixation in marine crustaceans, Metapenaeus affinis1 Parapenaeopsis styli(era1 Panulirus ornatus and Neptunus sanguinofentus in an AC field of specific strength varied with the lengths of animals tested, except in case of the last one where the increase in size of animals showed no significant effect on the effective period for different reactions. M. affinis in interrupted AC required threshold pulses for narcosis and fixation, which varied inversely with the length of the organism. Animals ~mbjected to current of higher effective period required Ion ger time for recovery in interrupted AC of 50 cfs. The period for narcosis and recovery of M. af(tnis did not vary significantly with repeated stimulations on the same organism.