1996

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    Uptake and Depuration of Phenol by Rohu (Labeo rohita) during a Chronic Sublethal Bioassay
    (Society of Fisheries Technologists (India)Cochin, 1996) Sherief, P.M; Nair, J.R. Rajasekharan; Mrithyunjayan, P.S
    Studies on the body residue levels in surivors of bioassay tests can provide valuable information on bioaccumulation and organism tolerance, while residue in survivors allowed to depurate in clear water could furnish data on detoxification and elimination of pollutants. Early juveniles of rohu (Labeo rohita) were exposed to five sublethal concentrations of phenol (0.1,0.5,2.0,5.0 and 10.0 mg I"1) and a control under a static-with 48 h replacement procedure with nominal concentrations for a period of 28 days. The phenol body residue concentration increased from 8.17 to 24.85 mg kg"' whereas the bioaccumulation factor decreased from 81.7 to 2.5 as the phenol concentration in water increased from 0.1 to 10.0 mg I"1. The 72 h percentage depuration of the accumulated body phenol residues ranged from 58.5 to 71.2% on exposure to clear water. The study reveals that phenol as a pollutant has a low bioaccumulation potency and a high rate of depuration in fishes.
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    Observations on the Growth Performance of Labeo dussumieri (Val.) in Mono and Mixed Culture Experiments
    (Society of Fisheries Technologists (India)Cochin, 1996) Kurup, B. Madhusoodana
    Growth performance and production potential of an indigenous carp of Kerala, Labeo dussumieri (Val.) has been studied by culturing it alone and also in combination with Indian major carps. In monoculture trials, L. dussumieri attained a mean weight of 392 and 356 g at stocking densities of 3000 and 4000 ha'1, respectively within a period of 10 months. In composite culture trials when L. dussumieri (Thooli) was reared along with Catla, Rohu and Mrigal in the ratio 1:1:1:0.5, and the average weight attained by Catla, Rohu, Mrigal and Thooli within a period of ten months were 671, 602, 474 and 322 g, respectively at a stocking density of 6000 ha"1 whereas at a higher density of 8000 ha"1, the average weights registered were in the order of 557, 506, 397 and 283 g, respectively. These would work out to a gross production of 2698 and 3043 kg ha"1 at stocking densities of 6000 and 8000 ha"1, respectively. The growth attained by L. dussumieri was apparently poor in the experiments when ratio of the above four species was maintained at 1:1:1:1. Physicochemical and biotic parameters of the ponds were also studied.
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    Effect of Dietary L-carnitine on Growth and Reproductive Performance of Male Oreochromis mossambicus (Peters)
    (Society of Fisheries Technologists (India)Cochin, 1996) Jayaprakas, V; Sambhu, C; Kumar, S. Sunil
    Cultured male tilapia was fed diets supplemented with various levels of L-camitine for 252 days and its growth and reproductive performance were evaluated. Carnitine administration produced growth enhancement, increasing with dosage. Carnitine stimulated feed conversion efficiency, better digestibility and high enzyme activity. The RNA-DNA and protein contents in the muscle and liver also increased concomitant with high growth rate. Carnitine induced lipid catabolism leading to reduction in lipid content of cultured fish, using lipid as energy source while sparing protein for anabolic processes. Significantly high GSI, sperm cell concentration, motility and percentage viability of the spermatozoa in carnitine treated tilapia were observed.
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    Static Bioassay with Liza parsia Exposed to Copper Sulphate, Zinc Sulphate and Lead Nitrate
    (Society of Fisheries Technologists (India)Cochin, 1996) Mohapatra, B.C; Rengarajan, K
    Short-term static bioassays were conducted on the brackishwater mullet, Liza parsia to determine the combined effect of copper sulphate, zinc sulphate and lead nitrate in the ratio 1:1:1. From probit analyses the LC50 values for 12, 24, 72 and 96 hours were found to be 160.5,152.2, 135.6,117.1 and 106.7 ppm, respectively. The toxicities of these elements were found to be "additive" in nature.
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    Effect of Hormones on Growth and Food Utilization of the Indian Major Carp, Cirrhinus mrigala
    (Society of Fisheries Technologists (India)Cochin, 1996) Jayaprakas, V; Sindhu, B.S
    The influence of human chorionic gonadotropin (HCG) and testosterone propionate (TP) at the dosages of 10 ppm and 3 ppm respectively, and their combination (HCG+TP) of 8 ppm and 1.5 ppm on the growth, food conversion, digestibility, enzyme activity, nucleic acid content. Oxygen consumption and ammonia excretion of the Indian Major Carp, Cirrhinus mrigala was assessed. The experiments were conducted in cement tanks (5x4x1 m) for 98 days by feeding hormones through fish meal based prepared diet having 35% protein. Growth of C. mrigala was high in hormone fed fishes than the control with the maximum growth recorded in the HCG treatment followed by HCG+TP, TP and control. Specific growth rate (SGR), food conversion efficiency (FCE), apparent protein and lipid digestibility were high in hormone fed fishes (p < 0.01) than the control. The enzyme activity in the foregut, midgut and hindgut showed marked variation with the highest activity noticed in the foregut followed by midgut and hindgut. The rates of oxygen consumption and ammonia excretion of hormone fed fishes were found to be not significantly different from control (P > 0.05). The hormones stimulate growth through increasing the appetite and enhancing food utilization and protein synthesis.
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    Technology Choice Under Risk in Marine Fishing
    (Society of Fisheries Technologists (India)Cochin, 1996) . Das, T.K; Neogy, R; Chakraborty, D
    A risk programming model has been developed for investment decision in marine fishing. The model has been applied on survey data in Digha coastal region ofWest Bengal in India. Results of the model have been analysed in the light of risk aversion.
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    Microbial Profiles of Non-Irradiated and Irradiated Semi-dried Fish
    (Society of Fisheries Technologists (India)Cochin, 1996) Vinh, P.Q; Alur, M.D; Nair, P.M
    Semi-dried non-irradiated anchovies (Anchoviella commersoni), initially exhibited the presence of Micrococcus (15%), Bacillus (60%) and Staphylococcus (20%) microflora. On the other hand, Bombay duck (Harpodon nehereus) and Vietnam scads (Alepes mate) were found to be contaminated predominantly by Bacillus and Staphylococcus sp. respectively. Irradiation (3 kGy) of semi-dried anchovies resulted in modification of microbial composition which comprised of Bacillus (50%) and Staphylococcus (50%), while microflora of semi-dried irradiated Bombay duck consisted of Bacillus sp. only. These results suggested that irradiation of semi-dried fish resulted in the elimination of Micrococcus leaving the survivors belonging to Bacillus sp. and Staphylococcus sp.
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    Length-Weight Relationships and Relative Condition Factor in Priacanthus hamrur (Forsskal)
    (Society of Fisheries Technologists (India)Cochin, 1996) Philip, K.P; Mathew, Kuruvila
    The length-weight relationship of Priacanthus hamrur was estimated and given by the equations. Males W = 0.00000638 L31133 and Female W = 0.00000811 L3 685. The b value showed significant difference between males and females. The b value computed for female did not show significant variation for the isometric value of 3 whereas in male the departure was found significant. In male and female the Kn value steadily increased up to about 100 mm and remained almost static up to about 150 mm and thereafter showed fluctuation. The seasonal change taking place in Kn value mainly indicate that in P. hamrur it is greatly influenced by feeding intensity rather than the cyclic change taking place in the gonads.
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    Ring Seines of South Kerala Coast
    (Society of Fisheries Technologists (India)Cochin, 1996) Edwin, Leela; Hridayanathan, C
    Ring seine or mini-purse seine is currently one of the prominent fishing gears in the artisanal fishery sector of Kerala. Since its introduction in mid-eighties, the ring seine has caused displacement of gears such as Thangu vala, operated from the traditional boat seine craft, Thangu Vallam. The design and operational features of the ring seine prevalent in the Alleppey - Cochin coast have been described in this paper alongwith a review of the important changes that have taken place in the design and operation of the gear, since its introduction.