A note on host specificity of the isopod parasite, Nerocila sp.

Host specificity is very strongly expressed in a great number of fish parasites, especially in the majority of ectoparasites like isopods. While engaged in the length frequency studies of the Indian Herring, Ilisha filigera (Val.) landed by bull trawlers of the New India Fisheries Company Limited at Sassoon Docks, the isopod parasite, Nerocila sp. was seen very commonly in Ilisha indica during the months of December and February. Though this has been already observed by Chidambaran| and Devidas Menon (1945) in Calicut, the case of host specificity among the species of the same genus has not been pointed out so far

The ribbonfish resources

Che ribbonfishes are an important group of food fishes in India and their annual average production during 1971-*82 was estimated at 55,300 tonnes which formed 4.3% of the total marine fish landings and occupied 7th position. The studies indicate that various species of ribbonfishes constitute substantial fishery in the States of Andhra Pradesh, Tamil Nadu, Kerala and Maharashtra showing considerable variations in the species composition, season^ abundance and production trends

Determination of the relative fishing powers (power factors) of the vessels of the Government of India deep sea fishing station, based at Bombay.

The Government of India Deep Sea Fishing Station at Bombay and the Offshore Fishing Stations at Veraval, Mangalore, Cochin, Visakhapatnam and Tuticorin have been employing in the exploratory fishing operations different types of power vessels which vary greatly in their gross tonnage, net tonnage, brake horse power, length of body, draught etc. even though most of them use more or less the same or similar types of otter trawls. It is well known that, suitably geared a larger boat would generally bring about a greater fishing mortality than a smaller one in a unit amount of time when fishing in the same ground. The capacity of a vessel to catch more or to catch less as compared with another vessel is independent of the density of the population and is related in some way to the makeup of the vessel itself. In computing catch statistics of different vessels, 'standardisation of fishing time according to their fishing powers' (Beverton and Holt 1957, P. 172) being essential, the present work has been attempted based on available data from the exploratory fishing operations of the vessels viz-, 'Jheenga', 'Bumili' and 'Meera' from Bombay

Large scale movements of Caranx sexfasciatus Quoy & Gaimard into the inshore areas of Madras

During the routine observations on the fishery along the Madras coast the authors visited the Mullikuppam landing centre in Madras City and observed the shore seine catches landed on 12th December, 1968. In Madras shore seines are operated within a distance of 1 km. from the shore at a depth of 4 to 8 metres during the anchovy fishery season, extending from November to May, While the catches in most of the nets on that day were anchovies, a huge quantity of Caranx sexfasciatus was observed in a haul which consisted of 925 fish weighing a total of nearly 3 tons. Enquiries with an elderly fisherman on the spot revealed that although the fish occur in large quantities in shore seine during this season in certain years no such huge catches were witnessed anytime in the past

Relative abundance of trawl fishes in the Bombay-Saurashtra waters

With the help of skilled Japanese technicians very intensive commercial fishing by two pairs of bull trawlers, ' Arnalla'—' Paj' and ' Satpati'—' Pilotan ' (each of 29 meters length, 250 BHP and about 91 gross tonnage) of the New India Fisheries Company, Bombay, was carried out from April 1956 to October 1963 in Bombay- Saurashtra waters, landing a total catch of 26,304 metric tons offish sold at a whole sale price of about Rs. 1.6 crores (Anon, 1965). The annual effort varied from 2,850.97 hours to 5,453.27 hours and the catch rates from 601.60 to 899.70 kg. per hour of trawling for a pair of vessels. Fishing by these vessels was preceded by exploratory buU-trawling by the Government of India cutters, M. T. Ashok and M. T. Pratap of the Deep Sea Fishing Station, Bombay during 1953-'55. These cutters, prior to 1953 using otter trawl had annual catch rates varying from 94.4 to 195.4 lbs. per hour of fishing, but during 1953-'55 when they had taken to the Japanese method of paired trawling (bull-trawling) the average catch per vessel had gone upto 1,562.4 lbs. per hour of trawling (Jayaraman et al., 1959). The present report shows that the best of trawling grounds in Bombay-Saurashtra waters are in Kutch region, the fishery potential of which was hitherto unexplored

Sea turtle research and conservation

Five species of sea turtles are known from the Indian Seas and all are today protected and are placed in Schedule I of the Indian Wildlife (Protection) Act, 1972. The Convention of International Trade in Endangered Species of Wild Fauna and Flora (CITES) which prohibits trade in turtle products places these species in Appendix I of the Convention. AUfive species have very wide distribution and there has been a traditional subsistence fishery for the green turtle Chelonia mydas along the Tuticorin Coast which has now been phased out. A new event in the recent past was the explosive development of an outlet for the olive ridley in the Calcutta-Howrah markets chiefly from the Orissa Coast, despite the Indian Wildlife (Protection) Act. This happens mainly during the mating and mass nesting of this species along the Gahirmatha Coast of Orissa and the capture is mainly in the gillnet fishing operations. This has been reported in detail in Marine Fisheries Information Service, Technical and Extension Series, No. 50 of this Institute. Incidental catch of turtles in fishing operations has been a matter of great concern and only an intensive extension programme can help to minimise the mortality from this source

Coastal Aquaculture - Mussel farming; Progress and prospects

During the seventies, the Central Marine Fisheri^ lleseardi Institute gave a lead in researches on mariculture and has carved for itself a pioneering role in the R& D programmes of mariculture in the countiy which has been well recognised. Impressed by the outstanding contributions made during the decade, the infrastructure facilities built up and, above all, the scientific and techni<ial competence it has acquittdi jm UNDP/ICAR Centre of Advanced Studies in Mariculture has been instituted at the Central Marine Fisheries Research Institute since June 1979. The Centre aims at providing postgraduate education in the new discipline of Mariculture and improvmg the quality of research through doct(»ral and post-doctoral research programmes in identified areas. One of the priority areas of mariculture in India is mussel culture. Although considered a poor relation of the oyster in Europe, mussel has one of the highest potentials in India for increaang production of protein- rich sea food. Mussel gives the highest conversion of primary producera ^hytojrfankton) to human food and culture production in column waters enhances the yield several fold. India has a traditional sustenance fishery for the mmsels at a few centres but the scope for increasing natural production from the existing beds is rather limited

Spawning periodicity of the ribbon fish, Trichiurus lepturus (F.), with a note on its rate of growth

The spawning periodicity of Trichiurus lepturus is briefly re-examined here in tlie light of certain recent observations. It is seen that this species spawns more than once in a year along the Madras coast and the two seasons are roughly around May-June and later in November-December. This fact also leads to a revision in the interpretation of the rate of growth of the fish. It is now estimated that the fish at the end of one year attains an average of 300 mm in length and that those above about 900 mm are just over four years

The present status of ribbonfish fishery in India

The ribbonfishes, of the family TrichiurkJae, an Important group of food fishes in India, registered an average annual catch of 53.475 tonnes during 1970-81. In this period, forming 4.25% of the total marine fish catch, thsy formed the 7th exploited fish group in the order of predominance. There are 8 known ribbonfish species in India (an identification key to the species is given in the beginning of thearticle) The information available on the various aspects of biology of each of these species is summarised, which clearly indicates that while our knowledge on the biology of Trichiurus lepturua, Lepturecanthus savale, Eupleurogrammus nwticus and Eupleurogrammus glossodon is considereble, we know little about the other species. Traditionally, the ribbonfishes are caught by boatseines, shoreseines, bag nets and gill nets, operating from nonpowered country crafts. But, during the last two decades, the small mechanized vessels (10-15 m long, with 15-100 hp engines) that are operating otter trawls, too, are increasingly landing ribbonfish. The fishery is confined to the depth-zone usually shallower than 50 m. T. lepturus, the most widely distributed, forms the mainstay of the ribbonfish fishery, contributing to the bulk of the landings along almost all our coastline. Data on spatial and seasonal variations in abundance, size and age composition in the commercial catches and diurnal movements and depthwise distributions of shoals of this species are therefore reviewed. Stock assessment studies show that, in the shelf region from Ratnagiri on the west coast round to Gulf of Mannar on the east, there had been an average standing stock of 67,200 tonnes of ribbonfish (mostly L Lepturus) in 1972-75, which is about 4 times what was actually landed from the region during the period. It therefore follows that a doubling of the catch will not adversely affect the stock in the region. Studies on the population dynamics of T. lepturus from the Kakinada area during 1967-71 has shown that the fishing mortality and the exploitation rates are low, at 0.3 and 0.17 respectively. The average annual stock and average standing stock along the Andhra and Tamil Nadu coasts are estimated at 85,000 and 48,000 tonnes, respectively, for T. lepturus, against an estimated annual average catch of 14,400 tonnes during 1967-71. It thus appears that the stock of T. lepturus along the east coast also is likewise underfishad, The need for extension of fishing operations into the Exclusive Economic Zone with larger vessels, equipped with suitable gears like bottom and pelagic trawls, is emphasized- Suggestions on future lines of research are given

Industrial fisheries off Madras coast based on exploratory surveys during 1973-1980

At the Madras Research Centre of CMFRI, there existed data for areas (Fig. 1) south of 15°40'N Upto the latitude zone of I0°40'N off Velanganni in depths ranging from 10 to 130 m for a eight year period From 1973 to 1980. The results of analysis of these data are presented here with a view to providing information on and extending our knowledge about the spatial and seasonal distribution of various indusirially important fisheries as also their resource potential along the north Tamil Nadu-South Andhra Coast