FT Vol.47(2)
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- ItemToxic Effects of Sodium Dodecyl Sulphate on Grass Carp Ctenopharyngodon idella(Society of Fisheries Technologists (India)Cochin, 2010)Sodium dodecyl sulphate, an anionic detergent finds various applications in household, industrial, laboratory and pharmaceutical preparations.This paper reports the histological, enzymatic and microbial changes found in the gills of Grass Carp (Ctenopharyngodon idella) induced by the acute action of Sodium dodecyl sulfate (SDS). A 96 h LC50 value of 7.7 mg/ l of SDS was obtained using static bioassay method. Sets of twenty grass carps each were exposed to nominal concentrations (2, 2.5 and 3 mg/l) of SDS for 30 days and the changes in the gills were monitored every tenth day. Extensive gill damage with necrosis and intraepithelial oedema was observed. This was accompanied by increased levels of antioxidant enzymes viz., superoxide dismutase and catalase. The gills of SDS treated fishes also showed an increased rate of microbial attack predominantly by Aeromonas sp, Micrococcus sp and Bacillus sp. Extensive necrosis, and increased rate of microbial attack suggested that SDS incites an acute inflammatory response. The morpho-histochemical changes in the gills provoked functional disorders viz., asphyxia and loss of osmotic and ionic regulation that may ultimately play a significant role in the mortality of Grass Carp exposed to SDS.
- ItemRedescription of Smooth Lantern Shark, Etmopterus pusillus (Lowe, 1839) from the EEZ of India(Society of Fisheries Technologists (India)Cochin, 2010)This paper presents more differentiating characters (Table 1) such as difference in the positioning of first and second dorsal fin, size of dorsal fin spines, shape of the gill slits and position of eye in relation to snout. Even though each morphometric measurement contributed relatively little for the overall differences, when all these small differences were considered together, it is possible to separate the species. The main difference mentioned by earlier authors (Compagno, 1984; Compagno et al., 2005) was in the shape of dermal denticles. But the characters presented in this study are useful for the field identification of E. pusillus.
- ItemProbiotic Effects of Bacillus spp. on the Growth and Survival of Postlarvae of Macrobrachium rosenbergii(Society of Fisheries Technologists (India)Cochin, 2010)Negative impact due to continued usage of antibiotics in aquaculture for growth promotion and disease control has necessitated research on alternative strategies such as development of probiotic strains, immunostimulants and vaccination. In this study, the probiotic effect of a Bacillus spp. on the growth and survival of postlarvae (PL) of Macrobrachium rosenbergii was studied. The Bacillus spp. under investigation was introduced in to the PL through culture tank water, feed and both. Changes in the bacterial load and flora, weight gain, percentage survival and changes in water quality parameters such as pH, dissolved oxygen, nitrite and ammonia were studied for a period of three months. There was no significant variation in the survival and weight gain of the PL of the experimental groups. However considerable improvement was noticed in the water quality parameters such as nitrite and ammonia concentration of the culture water in the experimental groups compared to the control group
- ItemMesh Selectivity of Drift Gillnet for Caranx sexfasciatus and Caranx tille(Society of Fisheries Technologists (India)Cochin, 2010)The gear selectivity and fishing power of different mesh sizes (13.5, 14, 14.5 and 15 cm) were investigated using experimental catch data of carangids Caranx sexfasciatus and Caranx tille. The selectivity and residual curves were generated using four different individual uni-normal (normal scale, normal location, gamma and log-normal) and bi-normal functions with four different mesh sizes. Selectivity parameters were estimated using the SELECT (Share Each LEngth Class Total) model which has been implemented in the software called GILLNET (Generalized Including Log-Linear N Estimation Technique). Model deviance, Dispersion parameter and Residual plots were used to determine the best fit of the data. The results demonstrated that bi-normal model and uni-normal log-normal yielded good fit for C. Sexfasciatus and C. tille respectively. Mesh sizes 14 and 14.5 cm performed better than the modeled in both the catch data. Modal length increased with mesh sizes. Bi-normal model yielded narrow selection range while log-normal model was of wider range. Shape and size of the selectivity curves were identical and uniform in size. Over dispersion was common in all selectivity models which in turn showed lack of fit irrespective of the models
- ItemIncidence of Food-borne Pathogens in Freshwater Fish from Domestic Markets of Mumbai(Society of Fisheries Technologists (India)Cochin, 2010)The present study indicates that the freshwater fish sold in Mumbai are of poor quality. Presence of coagulase positive S. aureus indicates unhygienic handlingRecovery of Salmonella and high coliform count warrant for strict adherence to Good Hygienic Practices in retail markets