Oxygen consumption in the mullet Liza macrolepis with special reference to swimming velocity

Oxygen consumption of tagged (plastic opercular tag) and untagged mullet L/z~ macrolepis (SMrrK), forced to swim up to 22 cm/sec (fish size: t0 era), increased proportionately to increase in swimming velocity above 5 era/see. The tag did not appear to cause any marked metabolic disturbance. The mean routine metabolic rate and the rate at 5 cm/sec were higher than the rates obtained for several higher levels of forced activity, possibly due to excitement and inefficient swimming at lower swimming speeds, as suggested by earlier workers. The interpretation of the elevation of a line drawn through the mean rates of metabolism at various swimming speeds, in relation to the standard metabolic rate, may be of value in quantitative expression of excitability of individual species

Low lethal temperatures of the fishes Liza Macrolepis (Smith) and Tilapia Mossambica Peters

Fry and Associates have made notable contributions in the field of temperature tolerance and resistance of fishes. While the high lethal levels of temperature of the group have been much explored there is more to be known about, their low temperature deaths

Physiological Studies in Relation to Fisheries

Studies on the physiological mechanisms and responses of fishes, which are closely linked with their ecology, have a significant role to play in fisheries development inasmuch as optimum survival of fishes is desirable and planned both in the capture and culture fisheries. While knowledge of the influence of various environmental factors on fishes are of direct value in formulating improved methods of fish culture, information on those responses of fishes which lead to their concentrations in fishable waters are of immense use in evolving more efficient methods of capture. Even though fish and prawn culture in India have existed for centuries the empirical knowledge gained so far can be perfected, j as pointed out elsewhere, only by acquiring a fuller understanding of the physiology of the I animals concerned

Observations on the Indian mackerel, Rastrelliger canagurta (Cuvier) from the trawl catches along the Bombay coast

Referring to the distribution of the Indian mackerel, Panikkar and Jayaraman (1956) mention that there is a distinct and unmistakable gap in the distribution of the major fisheries to the north of Ratnagiri and that north of this place shoals of mackerel are not known, but the species is widely distributed having been found in the Persian Gulf and the Bay of Bengal and stray specimens have also been taken in the trawls operated off Kathiawar. That the mackerel met with in the offshore catches are of importance is known from the statement that "a full picture of the distribution will depend on the location of the spawning grounds and the discovery whether there is any deep sea mackerel existing in offshore regions of the coast" (Panikkar, 1949). Mackerel in small numbers have been recorded on many occasions from the catches of the trawlers fishing along the Bombay coast. In one instance a dense shoal of mackerel was also encountered while the vessel M.F.V. 'Jheenga' was trawling about 32 kilometres off Bombay at depth of 35 metres, when about half a ton of mackerel was caught in a single haul. An attempt is made here to summarise the observations made on the catches of mackerel from trawlers working along the Bombay coast. The common occurrence of mackerel, though usually in small numbers, in the trawl catches prompts one to infer that the fish may at least occasionally move to the deeper waters

Influence of Phlogopite on the Physico-Mechanical Properties of a Porcelain

This research was conducted in order to obtain the optimum composition of phlogopite and sintering temperature of phlogopite in order to get the robust structure of porcelain. Clay, feldspar, quartz, and phlogopite were first sieved, mixed and compacted. Then, the samples were sintered at 1000°C to 1300°C. It is observed that the properties of the porcelain are highly depend on the composition of phlogopite and the sintering temperature of porcelain. Results showed that 10 wt% of phlogopite was the optimum composition and 1200°C was the optimum sintering temperature. The microstructure of the samples were analyzed by using two microscopes and it was evidenced that the pore in the samples were smaller and the structure are denser thus lead to a dense porcelain structure and improves the physical and mechanical properties of the porcelain

A note on the biology of the ‘Koth’, Otolithoides brunneus (Day)

While the importance of the ' Koth' as a trawl fishery of considerable importance in the Bombay Coast has been shown by Jayaraman et al. (1956) and Rao (1967), accounts on the biology of the species are lacking except for some observations on the scales and otoliths for age determination by Kutty (1961) and a few notes included in the studies on its fishery, cited above. With a view to a fuller understanding of the biology of the ' Koth' investigations on this fish occurring along the Bombay coast were made during the years 1958-1961, a summary of the results of which is presented in the present note

Scales and otoliths of the 'Koth'Otolithoides brunneus (Day)as age indicators

Growth rings on the scales and otoliths of 'Koth' have been recorded by Karandikar and Thakur (1951). Mention of growth checks on the scales of this fish and their probable utility in -age determination has also been made by Seshappa (unpublished). Studies on the scales and otoliths of 'Koth' from the local 'dol' net catches landed at Bombay and the catches of the trawlers working along the Bombay coast were begun by the author in February 1958 with a view to assess their value in age determination of the fish. Material for the present study was also collected subsequently from the gill-net catches at Bedi in the Gulf of Kutch

Evolution of eco-friendly coastal aquaculture/mariculture technologies

Global aquaculture production from marine waters, which accounts Jor 54% of total production, increased from 6.86 miRion metric tonnes in 1987 to 18.51 mUlionmtin 1996, registering an increase of 270% over the decade. India's marine/coastal aquaculture production is almost restricted to shrimps, as the production of marine finfrshes, moRuscs and sea weeds are negligible. An index of Biodiversity Utilization for Aquaculture (BUA) calculated for India is quite low (0.13) when compared to the highest (0.51) for Taiwan and Korea (RoK)

Economics of the indigenous fishing units at Cochin: a case study

During the last three decades we have witnessed progress in the marine fisheries sector, particularly in the introduction of mechanised fishing crafts, use of synthetic material for gear and development of infrastructure facilities. The traditional fisheries sector, still using indigenous crafts such as catamarans and canoes, has taken advantage of nyion in fabricating their fishing gear. On an average, our annual marine fish production is about 1.3 million tonnes, of which nearlyOO per cent is accounted for by traditional fishing methods from a narrow belt along our coast. In spite of this importance, hardly any serious study has been carried out on the economics of operation of the artisanal fisheries in the country. The present report by Shri A. Noble and Shri V. A. Narayanankutty of this Institute on the economics of the indigenous fishing units at Cochin is a case study on some aspects of the small-scale fisheries of the Cochin area. The study is based on several years data collected by the Institute and is but a small step towards understanding the problems of traditional fisheries. The Institute has programmed to take up similar studies in other regions along our coast. The issue of this Number on the occasion of the Seminar on "The Role of Small-scale Fisheries and Coastal Aquaculture in Integrated Rural Development" is considered timely as it focuses attention on an area needing intensive studies and critical evaluation of available information to assist in coastal rural development. E

Oxygen consumption, ammonia excretion and random activity in Penaeus semisulcatus, Macrobrachium malcolmsonii and Paratelphusa hydrodromus with reference to ambient oxygen

Oxygen consumption, ammonia excretion and random activity in relation to ambient oxygen have been investigated in a marine prawn, Penaeus semisulcatus, a freshwater pravm, Macrobrachium malcolmsonii and a freshwater crab, Paratelphusa hyiirodromus. At normoxia, P. semisulcatus maintained an ammonia quotient (A.Q.=volume or mole; mole relation of ammonia excreted to oxygen consumed) of about 0.06, M.malcoimsonii maintained an A.Q. of about 0.08 and P. Hydrodromus an A.Q. of about 0.2s. Under hypoxic conditions all these three crustaceans showed high ammonia quotients. The 2 to 5 fold increase in A.Q. values in hypoxic conditions indicates increased protein degradation and may be of value in combating acid base balance as in the case of fishes. The random activity increased in hypoxic conditions in the case of P. semisulcatus and M. malcolmsonii whereas in the case of P. hydrodromus the activity decreased in hypoxic conditions indicating a dichotomy in behaviour which appears to have ecological significance. The metabolic rate decreased in hypoxic conditions in all the three species