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Research Article
Feb 29, 2016
A Study on the Determination of Heavy Metals in Sediment of Fish Farms in Bangladesh
Heavy metals in mud surface sediments have been determined to assess environmental pollution of the selected fish farms in Mymensingh, Bangladesh. Surface sediment samples (0-15 cm) from 20 ponds of a fish farm were collected in February 2014 with a single core sampler and were analysed to measure the concentrations (mg/Kg DW) of Zinc (Zn), Lead (Pb), Cadmium (Cd), Nickel (Ni) and Chromium (Cr) by atomic absorption spectrometry using a VARIAN model AA2407 in Bangladesh Agricultural Research Institute’s laboratory. The measured concentration of heavy metals in the present study was in order of, Zn > Cr > Ni > Pb > Cd which are quite similar to the findings of other sediment of pond mud. The mean concentrations of Zn, Pb, Cd, Cr, Ni observed in the present study were 208, 14.845, 0.009, 63.054 and 58.665 mg/kg respectively. The ranges of the measured concentrations (mg/kg) in the total sediments were 11.5-18.5 for Pb, 0.007-0.011 for Cd, 53.5-77.3 for Cr, 50.8-66.4 for Ni and 100-250 for Zn. The concentrations of Zn and Ni in all sediment samples were above the US Environmental Protection Agency’s (USEPA) guideline for severely polluted sediment and the concentration of Cr falls under the moderately polluted range. The metal Pb and Cd concentrations are well below the regulated level as per USEPA. Therefore, the study results revealed that the pond mud sediment quality in Mymensingh region might be considered as highly and moderately polluted for Zn, Ni and Cr respectively.
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Research Article
Feb 26, 2016
Pathological Findings of Experimental Aeromonas hydrophila Infection in Golden Mahseer (Tor putito ... ra)
ntroduction: Mahseers, belong to the family Cyprinidae, are well renowned for the excellent game as well as food fishes. Various aspects simultaneously considered towards the domestication of this fish species also include the study of fish health issues, preventive and remedial programmes for sustainable aquaculture. Experimental studies can be conducted in the control condition to study the pathological symptoms during bacterial infection. Considering the bacterial pathogens as a major constraint for aquaculture, the present study was carried out to standardize the bacterial concentration of A. hydrophila for the experimental challenge of Golden Mahseer for the first time, and various clinical changes were also monitored during the infection. Materials and methods: A total of 140 live fishes were acclimatized to the laboratory conditions for experimental study. A constant water quality was monitored during the acclimation period and throughout the experiment. The test group was injected with A. hydrophila and various physiological, biochemical and tissue level changes were observed during the experiment in comparison to phosphate buffer saline (PBS) injected control group. Results: LD50 value of A. hydrophila for Golden Mahseer was successfully standardized. Clinical signs including weakness, slower movement, swimming closer to the surface, fin haemorrhages and red patches at the gut region were observed. Enlargement of spleen followed by tissue necrosis along with signs of haemorrhagic septicaemia was also seen in infected fishes. The necrosis of hepatocytes was observed in the histological section of liver tissue. The bacterial infection increases the superoxide dismutase activity and cortisol level in Golden Mahseer. Conclusion: The LD50 value of A. hydrophila for experimental challenge studies on Golden Mahseer is 1.74 × 105 cfu per 100 g of body weight. The symptoms of severe bacterial haemorrhage were observed. Necrosis of hepatocytes was observed in infected fishes. The superoxide dismutase activity and cortisol level also increased in infected fishes. A. hydrophila was confirmed to be the etiological agent which was re-isolated using spread plate method and confirmed by 16s rRNA sequencing.
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Research Article
Feb 20, 2016
Macrobenthic Community Structure - An Approach to Assess Coastal Water Pollution in Bangladesh
A research on the assemblages of benthic macro faunal community in the coastal areas of Bangladesh was conducted during February-March, 2015 following the standard methods to assess the status of environmental pollution. The abundance (r=0.846) and species richness (r=0.864) of the macrobenthic communities were significantly influenced by the water salinity of the sampling sites (p ≤ 0.05). Both the study areas namely the Bakkhali River Estuary and the Meghna River Estuary showing the highest (3909 ± 540 ind./m2 ) and lowest (2236 ± 689 ind./m2 ) density of benthic macrofaunal abundance respectively might be considered as moderately polluted areas according to the results obtained from Shannon-Wiener index of species diversity (2.69 ± 0.13 and 2.00 ± 0.11 respectively) and Margalef’s species richness (2.21 ± 0.43 and 1.36 ± 0.11 respectively). Therefore, it is plausible that the macrobenthic community explained in the present study might be a key future outline to assess the status of coastal water pollution of those concerned areas of Bangladesh.
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Research Article
Feb 17, 2016
An Introduction about Genotoxicology Methods as Tools for Monitoring Aquatic Ecosystem: Present St ... atus and Future Perspectives
Pesticide residues with genotoxic potential reach the aquatic environment and constitute a major issue that give rise to concerns at local, regional, national and global scales. Fish serves as an excellent genetic model for the genetic hazard assessment as they are very sensitive to changes in their environment. As there is a close consortium of DNA damage, mutation and induction of various types of genetic disorders, genotoxicity tests like chromosomal aberration test, micronuclei and comet assay are gaining credence and since past few decades many tests have been developed for evaluating genetic alterations in aquatic organisms. These tests rely on the premise that any change to DNA may have enduring and ardent consequences. Thus, the first aim of the genotoxicology is to describe the outcome produced by toxic substances in various test species, but only from the genetic point of view and to draw conclusions that can be extrapolated to man. This review summarizes the genotoxicity tests developed till date and the role of piscine model in genotoxicology. The text also delves the latest knowledge and thinking on these cardinal approaches for the assessment of aquatic environmental health, management and conservation, besides providing useful repository for the researchers especially dealing with aquatic genotoxicity tests. The perspectives for further research on the use of genotoxicology tests were also highlighted.
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Research Article
Jan 10, 2016
The Fish Catching Devices with their Efficacy and Cost-benefit Analysis in the Towkak River in Ass ... am and Nagaland, India
Approach had been made to study the various fishing techniques in the Towkak River in Assam and Nagaland. The combination of both hills and plain regions along the river, showed a higher diversity of fishing gears and equipments. The cost benefit and efficiency analysis results that Cast net was most efficacious fishing gear and also possesses the highest value of Mechanization Index (MI) which portrayed, a popular and most used gear.
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Research Article
Dec 27, 2015
Food and Feeding Habits of Cyprinus carpio Var. communis: A Reason that Decline Schizothoracine Fis ... h Production from Dal Lake of Kashmir Valley
In this paper, we studied the food and feeding habits of exotic Cyprinus carpio Var. communis. The results obtained by analysing the gut contents of common carp showed that on an average basis, detritus formed 43.5% of total food, while the remaining food (56.5%) consisted of plant (31.21%) and animal matter (25.29%). The fish was designated as detri-omnivore with bottom feeding habit. Gastroosmatic index (Ga.S.I.) recorded its highest value during July (6.28), while lowest value was recorded in February (3.34).The index remained generally high during the warmer months, followed by a gradual decline with the approach of winter. On comparing, food and feeding habits and Ga.S.I. of exotic common carp with that of endemic schizothoracines was found almost similar and there might be existing a feeding competition between them, which might be one of the cause that declined endemic schizothoracine fish production from Dal Lake of Kashmir valley.
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Research Article
Dec 20, 2015
Post-harvesting and Major Related Problems of Fish Production
Fish is an important source of animal protein in the especial cases of African countries, where the combine forces of high cost, disease, low genetic potentials of indigenous species among other factors have raised the cost of livestock almost beyond the reach of the low income groups. Fish becomes readily accessible source of animal protein but this alternative is also threatened by poor post-harvest techniques in African countries, which have resulted in massive losses. This paper discusses about the most important type of post-harvest fish lose. It also describes the cause of these loses, the factors that affect or facilitate such problems. It also briefly describes the mechanisms of problems or conditions that resulted in fish lose. The losses can be physical lose, quality lose, economical or nutritional lose, and also the most important cause of lose is spoilage. Fish lose due to spoilage is estimated to be 10 to 12 million tons per year which accounts 10% of total production of fish. In general post-harvest fish lose results in low income of the society, low quality (unhygienic) fish and available fish products are very low. It also results in low diet or low nutritional value which gives in unhealthy and poor population.
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Research Article
Dec 16, 2015
Snails and Fish as Pollution Biomarkers in Lake Manzala and Laboratory A: Lake Manzala Snails
Physiological, hematological and biochemical parameters have been used as biomarkers for water quality in snail samples collected from Lake Manzala. The results showed significant increase in AST, ALT, and ALP in planorbis and Physa snail samples collected from Dakahlya site in Lake Manzala. Most of snails are collected from of Port-Said and Dakahlya sites showed significant increase in urea. On the other hand, alteration in creatinine values in samples from different lake sites was recorded. Significant increase of total protein level and total bilirubin was obtained in all samples. Most of snail samples showed significant decrease in hemocytes count. The oxidative enzymes (CAT, GGT and GST) recorded alteration in their activity. Regarding Histopathological observations, in the foot region of Biomphalaria snails collected from Port Said and Dakahlya governorates are the most affected. The head foot showed splitting in the longitudinal and oblique muscle fibers and increased empty spaces within muscle. Shrinkage, focal areas of necrosis, large fat vacuoles and enlargement were observed in the salivary gland. Snail’s ganglia showed enlargement of neurosecretory neurons, degeneration with large vacuoles and fibrosis. hepatopancreas became much more distorted with necrosis, atrophy, degeneration and fat vaculation especially in Port Said and Damietta samples. Also, hepatopancreatic acini filled with different developmental stages of S. mansonai cercariae were observed in Biomphalaria snails collected from Port Said. Severe degenerative changes were observed in most of gonad’s cells including ova and sperms especially in snails collected from Damietta. Also, Biomphalaria snails collected from Lake Mazala showed accumulation of heavy metals in the head foot tissues. In conclusion, the severe alteration and degeneration recorded in the physiological and hematological parameters and also histopathological observations are clear evidence for the pollution of the water from which these snails were collected
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Research Article
Dec 16, 2015
Population Dynamic and Stock Assesment of White Seabream Diplodus sargus (Linnaeus, 1758) in the Co ... ast of North Siani
In the present study fisheries, population dynamic and stock assessment of Diplodus sargus in the coast of North Siani (Eastern Mediterranean, Egypt) studied. Length weight relationship, catch length structure, length scale relationship, total length by the end of each year of life, growth in weight, Von Bertalanffy parameters, the values of (total, natural and fishing mortalities), survival rates, Approximate maximum length with the highest biomass of D. sargus and approximate maximum age tmax. Also Cohort analysis (VPA, age based) which represent the estimated values of the population numbers, survivors, natural and fishing mortalities for each year of life of D. sargus were studied.
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Research Article
Dec 10, 2015
Surface Topography of the Anterior Adhesive Apparatus of the Gill Monogenean Parasite Diplectanum s ... p. diesing, 1858, with some Surface Criteria
Surface topography of anterior adhesive apparatus was studied of the gill monogenean parasite Diplectanum sp. Diesing, 1858 inhabiting the marine water fish Dicentrachus sp. using SEM. The study revealed that the parasite has three head lobes on each anterolateral region of the head; each lobe accommodates a single, ventrally located adhesive sac. These sacs receive secretion from glands openings that located on the lumen of these sacs. Rodshaped secretory bodies and granular irregularly shaped bodies which may be secretory bodies of the adhesive gland cells were seen open into the adhesive sacs. The tegument of the anterior adhesive area of Diplectanum sp. was characterized by many microvillous like structure. The possible functions of these distinctive features in the temporary attachment are discussed. Numerous adhesive papillae presumed sensory structures were found associated with the tegument of the anterior adhesive area and ventral surface of the body. A single ciliary structure supported by a collar of tegument occurs singly close to the mouth opening. It is suspected to be ciliated sensory ending serve to locate feeding sites. The possible functions of these presumed sensory structures were discussed. The parasite adaptation in its microhabitat in facing the strong water current inside the host fish gills was discussed.
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Research Article
Dec 10, 2015
Loose Shell Syndrome (LSS) in Litopenaeus vannamei grow-out Ponds and its Effect on Growth and Prod ... uction
Loose shell syndrome is a chronic disease in shrimp industries, in the present study, two different L. vannamei grow-out ponds (normal and LSS infected ponds) were selected to study their water quality parameters. Average Body Weight (ABW) and Daily Growth Rate (DGR) in Prakasam district of Andhra Pradesh. The results of the present study showed, there was no much variation in water quality parameters between both the ponds except pH. The daily growth rate and average body weight was higher in the normal pond than LSS infected one. The maximum LSS prevalence was reached up to 20%. The infected shrimps became sluggish and negative allometric growth. The results of present study revealed that the LSS infected shrimps showed lower production in the grow-out pond.
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Research Article
Nov 24, 2015
Changes in Physico-chemical Parameters at different Sites of Manasbal Lake of Kashmir, India
In an aquatic ecosystem, the density and diversity of organisms depends on availability and quality of water. During the present study an attempt was made to analyse some of the important physico-chemical parameters of the water samples at three different sites of the Manasbal Lake to check the pollution load. Various parameters were analysed for a period of six months on monthly intervals by following standard methods. Among the various parameters recorded the overall Air temperature ranged from 7.2°C to 30.2°C; Surface water temperature ranged from 6.1°C to 26.5°C; Secchi-disc transparency from 1.5 m to 4.5m; Conductivity varied from 149 to 292 μScm-1; Dissolved oxygen from 2.4 to 8.8 mg L-1; Free Co2 from 2.0 to 14.0 mg L-1; pH from 8.1 to 9.2; Total Alkalinity varied from 126 to 243 mg L-1; Chloride values ranged from 5.9 to 33.5 mg L-1; Total Hardness ranged from 119 to 218 mg L-1; Ammonical Nitrogen varied from 27 to 193μg L-1; Nitrate Nitrogen varied from 31 to 286 μg L-1; Ortho-Phosphate Phosphorous varied from 4.3 to 33.0 μg L-1 and Phosphate Phosphorous ranged from 83.0 to 261 μg L-1. Almost all the above parameters showed that the pollution load is increasing especially at littoral sites due to agricultural run-off and human settlements disposing sewage, besides anthropogenic stresses in the catchment area. The pH of water of this lake was higher due to calcium intrusion from Kondabal area. Hence, the present study urges the need for immediate remedial measures for protection and conservation of this lake in order to save it from further deterioration.
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Research Article
Nov 15, 2015
Importance of Transgenic Fish to Global Aquaculture: A Review
Many faster growing transgenic fish including both cold water (salmon, trout) and warm water (tilapia, carp) species have been produced. The development of transgenic fish can serve as excellent experimental models for basic scientific investigations, environmental toxicology and in biotechnological applications. The fast growth characteristic of GH gene transgenic fish will be of great importance to support aquaculture production and economic efficiency. The transgenic fish are efficient feed converter, thus more economical for the fish farmer as the feed accounts for 60-70% of total cost in aquaculture.
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Research Article
Oct 27, 2015
Morphological and Molecular Characterization of Diplozoon kashmirensis; D. aegyptensis and D. gupta ... i Collected from Fishes of Kashmir ValleyIndia
The study reports the results of molecular characterization of the Internal Transcribed Spacer (ITS) of ribosomal DNA of 3 Monogenean species using polymerase chain reaction (PCR), nucleotide sequencing and construction of phylogenetic trees from different fish hosts of Kashmir. The present study shows that the size of the amplified product is 873bp long for D. kashmirensis, 1120bp long in D. aegyptensis and 687bp long in D. guptai revealing that there are intraspecific differences in their base pair lengths. Guanine and Cytocine (G+C) content of three Diplozoon species was found nearly constant for three species i.e., 47% (D. kashmirensis); 47% (D. aegyptensis) and 48% (D. guptai), this GC richness contributes to physical attributes of RNA structures, as there is correlation between GC content and optimal growth temperature. An important observation during the present study has been noticed that Schizothorax niger is infected by all the three species of Diplozoidae; D. kashmirensis; D. aegyptensis and D. guptai, but when all six fishes were collected simultaneously, parasitism by all the parasite species was never observed. Phylogenetic trees Maximum Parsimony (MP), Maximum Likelihood (ML) and Neighbor Joining (NJ) showed that D. kashmirensis and D. aegyptensis share a common host Carassius carassius and S. niger.
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Research Article
Oct 24, 2015
Present Yield Status, Percentage Composition and Seasonal Abundance of Shark in Two Geographically ... Important Zones of Bangladesh
A study was carried out during January-December (2014) in two selected shark landing centers; BFDC Fish harbor, Cox’s Bazar and Fishery Ghat fish landing center, Chittagong situated at the North-eastern part of the Bay of Bengal. Data were collected through semi-structured interview, case study, frequent visit to the informants found in and between the trade channels. A total of 9 shark species belonging to 3 families (Carcharhinidae, Hemiscylliidae and Sphyrnidae) were recorded. It was found that sharks were exploited mostly at small sizes (45%) in those landing centers. The highest and lowest yield were found in the month of January and July respectively at Chittagong whereas November and July at Cox’s Bazar. The highest and lowest landed number was found in November and July respectively at both the landing centers. Dog shark was the most dominant species followed by Hammerhead shark in terms of yield and landed number at Chittagong and Cox’s Bazar contributed 55.794 MT (60% 90 ) and 17.675 MT (19%) among the total yield and 174,877 ( 83%) and 25,733(12%) landed number respectively. Yield and landed number of other species contribution altogether were only 21% and 5% respectively of total. Total yield was found 6 folds in Cox’s Bazar than that of Chittagong. Abundance reveals that the highest catches of shark were found during October to December (42%) and the lowest catches during January to March (16%). Yield of shark was found to be declining than the previous years and a clear deviation of seasonal abundance is also occurring. As there is no gear size limitation or seasonal restriction in the Fish Act, small sized sharks were found to be caught mostly in those landing centers which may also pose a threat to shark species composition in the Bay of Bengal region, Bangladesh.
