Journal of Fisheries (University of Rajshahi)
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Evaluation of extracellular enzyme-producing autochthonous gut bacteria in walking catfish, Clarias batrachus (L.)
Get PDFThe present study was carried out to screen autochthonous gut bacteria in freshwater air breathing walking catfish, Clarias batrachus Linnaeus. Altogether, 100 extracellular enzyme-producing bacteria were isolated from the foregut (FG) and hindgut (HG) regions. Data were presented as log viable counts g-1 gut (LVC). The occurrence of heterotrophic bacterial population was higher in the FG region (LVC = 8.25) than the HG (LVC= 7.3). Similarly, proteolytic, amylolytic and lipolytic bacteria in FG outnumbered (LVC=7.25, 6.77 and 5.23 respectively) the HG (LVC=6.38, 5.58 and 4.04 respectively). However, occurrence of cellulolytic bacteria in both, FG and HG was less (LVC=2.1 and 1.34 respectively) in comparison to the other extracellular enzyme-producing bacteria. Out of the 100 bacterial isolates, 22 isolates were primarily selected through qualitative assay of extracellular enzyme activities. Among them, 3 promising isolates were chosen as potent extracellular enzyme producers on the basis of cumulative scores (≥11) of the qualitative assay and quantitative enzyme assay. Maximum protease activity was revealed by the strain FG10 (201±2.40U), while FG43 exhibited maximum amylase (208.3±10.8U) and lipase (4.73±0.05U) activities. Among the strains isolated from the HG, the highest protease (188.3±1.2U), amylase (97.6±0.46U) and lipase (3.7±0.11U) activities were recorded with the strain HG01. 
Investigation on changing pattern of health status of juvenile Hypophthalmichthys molitrix from farming systems in Bangladesh
Get PDFAn experiment was carried out to investigate the health status of Hypophthalmichthys molitrix among three different fish farms at Mymensingh district of Bangladesh. Fish sampling and water quality parameters were collected on a monthly basis. Samples of skin, muscle, gills, liver and kidney were examined through histological technique. Results from water quality parameters suggested that water temperature had a distinct effect on fish health of H. molitrix, which was mostly evident during the colder months. Infectious symptoms were usually evident in July to October and the severity of pathology was increased in November and December. These were evident from their clinical signs that include scale loss, haemorrhagic lesion, and reddish spots or from their histopathological symptoms such as necrosis, pyknosis, inflammation, haemorrhage, hypertrophy, missing of gill lamellae, vacuums, tubular and pillar cells degeneration, inflammation, clubbing, and suspected bacterial colonies. Results suggest that the health condition of the fishes from BAU fish farm was the best over the other two farms, whereas Government fish farm followed by NGO fish farm were severely affected with EUS, protozoan and bacterial infection. Moreover, internal organs like liver and kidney were more affected than skin, muscle and gills
Seasonal variation and community structure of fishes in the Mahananda River with special reference to conservation issues
Get PDFThis study was carried out in the Mahananda River from January to December 2013 with a view to determining the seasonal variation and community structure of fishes along with some conservation issues. Monthly sampling was carried out using traditional fishing gears and fishes were identified based on morphometric and meristic characters. A total of 4082 individuals of native fish species were captured, analyzed and classified into 62 species belonging to 46 genera, 25 families and 9 orders. Cypriniformes and Siluriformes were the dominant fish orders represented by 19 species each and the most abundant family was Cyprinidae (14 species). In addition to indigenous individuals, 9 individuals of 2 exotic fish species (Hypophthalmichthys molitrix and Pangasius hypophthalmus) were also recorded. Among three sampling sites, S-1 was the most diversified in terms of not only the number of individual fish but also the number of species present represented by mean (±SE) individuals of 151.50±25.22 and species of 25.58±3.91. Three distinct fish groups of fish families were revealed from the cluster analysis of similarity. To improve the situation, control of illegal fishing gears, establishment of sanctuaries and legal protection for threatened species are recommended
Transferable chloramphenicol resistance determinant in luminous Vibrio harveyi from penaeid shrimp Penaeus monodon larvae
Get PDFAntibiotic-resistant luminous Vibrio harveyi strains isolated from Penaeus monodon larvae were screened for the possession of transferable resistance determinants. All the strains were resistant to chloramphenicol and the determinant coding for chloramphenicol resistance was transferred to Escherichia coli at frequencies of 9.50x10-4 to 4.20x10-4. The results probably suggest the excessive use of chloramphenicol in shrimp hatcheries to combat luminous vibriosis
A study on sutijal (purse net) in the Chalan Beel
Get PDFThe present study on fishing technique using sutijal (purse net) in the Chalan Beel was conducted for a period of 3 years from July 2011 to June 2014. Net description, operation details and catch composition were studied through field survey in different parts of studied wetland. Three different categories of sutijal were recorded. Catch composition revealed that all types of aquatic organisms are being caught by this net. Benefit-cost ratio of studied fishing net was also calculated. Frequent fishing by this net, especially in streams of remote areas of the Chalan Beel resulting in decline of fish species and abundance. Appropriate management steps are recommended to get rid of this destructive fishing gear
Spatio-temporal variability in hydro-chemical characteristics of coastal waters of Salimpur, Chittagong along the Bay of Bengal
Get PDFDiverse seasonal characteristics of hydro-chemical parameters in the coastal zone are significantly related to aquaculture development. In this paper, general water quality condition derived from laboratory analysis from the coastal waters of Salimpur, Chittagong is presented. Samples were collected from onshore and offshore site of two adjacent coastal locations named as North Salimpur (experimental location) and South Kattoli (control) during a monsoon and a dry season spanning 2013-14. The spatio-temporal variability of studied parameters were found as air temperature 26.5-32.5 ˚C, water temperature 23-33 °C, pH 7.1-7.9, DO 4.29-7.11 mg/L, BOD 1.10-3.25 mg/L, salinity 1.6-21 ppt, EC 3.40-35.68 mS/cm, TDS 2.02-21.99 g/L, TSS 0.62-2.76 g/L, transparency 4.5-14 cm, precipitation 64-1992 mm, NO2-N 1.94-2.58 µg/L, PO4-P 0.45-1.84 µg/L, SiO3-Si 130.46-956.31 µg/L during investigation period. Average values of physicochemical parameters were found to be in compliance with standard guidelines. The ship breaking activities near experimental location possess negative impacts on local geomorphology, freshwater inputs, precipitation and aquatic environment as well. Moreover, wind driven forces, tidal action, wave characteristics and changes in monsoon pattern regulate the coastal processes. This research suggests the importance of regular monitoring to assess present status of water quality and future prospect of aquaculture in the Chittagong coastal zone
Eutropiichthys vacha (Hamilton, 1822), a threatened fish of Indian subcontinent
Get PDFEutropiichthys vacha (Batchwa vacha) is a freshwater catfish species having high economic value. It is a very popular table fish among the consumers due to high nutritional value and taste. Just recently small specimens of this species have also made their entry in ornamental fish markets. Recently due to number of reasons, populations of this fish species are facing the threat of extinction. It has already been documented as Endangered in India and Critically Endangered in Bangladesh. The present report has been prepared to summarize the information available on different aspects of this threatened fish species as well as to point out the possible measures that should be considered for its conservation
Directional preference of European lobster (Homarus gammarus) movements on the Yorkshire Coast
Get PDFRecaptures of 838 tagged Homarus gammarus individuals identified a directional preference, with bearings from release to recapture concentrated along a North-West to South-East axis, aligning with the predominant current direction for the study site
Water and sediment quality characteristics of medium saline traditional shrimp culture system (bheri)
Get PDFQuality of water in shrimp culture ponds depends on several physical, chemical and biological processes. In this study, the physico-chemical characteristics of water and sediment samples from inlet, pond and outlet of a traditional shrimp culture pond, locally called as bheri, were examined for nine months from March to November 2011. Majority of the physicochemical parameters of bheri were well within the optimum levels. The average BOD values in pond water and outlet water were 2.03 ppm and 2.33 ppm, respectively. In pond water, the levels of ammonia were from 0.012 to 0.033 ppm, which was well within the safe level (<0.1 ppm). The present study recorded low levels of nitrite (0.0037 to 0.0043 ppm) and nitrate (0.056 - 0.091 ppm) in pond water, which was within the safe levels recommended for shrimp farming. These physicochemical parameters did not affect the cultured shrimp as there was no incidence of diseases or growth retardation during the culture period. The effluent water characteristics also did not vary much and well within the recommended levels for protecting the coastal ecosystem. It is unlikely that the traditional shrimp culture pose any adverse environmental effect when effluents are discharged into the open coastal ecosystem
Fisheries exploitation of the Halda River, Bangladesh
Get PDFFish exploitation of the Halda River was investigated for two years period from January 2007 to December 2008 to know the variation of CPUA (Catch Per Unit Area kg.ha-1year-1) among the three studied sections, months and between two years. The mean CPUA for pooled data was 295.685, 433.219, 524.449 and 411.887 kg.ha-1year-1 for the year 2007 and 415.987, 636.808, 566.515 and 527.545 kg.ha-1year-1 for the year 2008 in upstream (section 1), midstream (section 2), downstream (section 3) and over the total study area of the River Halda respectively. Analysis of variance showed highly significant difference of CPUA among gears and months. No significant difference of CPUA was observed among sections. Combined CPUA during 2008 observed higher and statistically significant than previous year