Catfish Mystus Research Articles

Mystus vittatus (Hamilton, 1822)’un doğal ve kültür ortamındaki boy-ağırlık ilişkisi ve kondisyon faktörü

The Asian catfish Mystus vittatus is very popular food and ornamental fish in India. Length- weight relationships and condition factors of this fish are crucial component in fishery managements. The objective of this study is to investigate the relationships between the length, weight, condition factor (K), relative condition factor (Kn) and modified condition factor of Mystus vittatus (Hamilton, 1822). The study is particularly focus on analysing the sex wise variations in growth patterns, productivity, stocks, and conservation in two different habitats, natural habitat and biofloc system. The findings show that the species did not strictly follow the predicted cube law and showed allometric growth patterns in both habitats. The "b" value varies from 2.72 to 3.12, the condition factor (K) ranges from 0.587-1.50, modified condition factor ranges 0.54-2.26 and relative condition factor (Kn) ranges from 0.71-1.65. Natural habitats had the highest mean values for the regression parameter (b), condition factor (K), and relative condition factor (Kn). For male, female, and combined sexes in two different habitats, the R2 values show a statistically significant relationship between weight and length. The correlation analysis indicates some positive and negative significant relationships among sex, length, weight, condition factor, and relative condition factor. Therefore, there is significant relationship between condition factor, relative condition factor length, weight in two different habitats and it varies between male and female within same habitat. Thus, this finding will help to fishery managers for long term strategy development of Mystus vittatus in both natural as well as biofloc system.

Zinc modulates hypothalamo-pituitary-gonadal-liver axis to impair reproduction in female Mystus vittatus (Bloch, 1794).

The present study investigated the effects of zinc on the hypothalamo-pituitary-gonadal-liver (HPGL) axis of the bagrid catfish Mystus vittatus. Female fish (pre-ovulatory and ovulatory phases) were exposed to zinc sulphate at 1/10th of LC50 (5.62mg/L) for 60days and sacrificed at every 15-day interval to collect tissues. Zinc concentration in all tissues was significantly higher in the metal-exposed group at all exposure durations compared to control for both phases. Metallothionein (MT) levels increased in the brain, liver and ovary of fish from both phases with exposure duration. Reactive oxygen species (ROS) generation in the brain, liver and ovary tissues increased with exposure duration at both reproductive phases while serum cortisol levels in ovulatory fish increased significantly compared to pre-ovulatory. Condition factor, gonadosomatic index and hepatosomatic index decreased in Zn-exposed fish. Brain GnRH and kisspeptin levels decreased significantly in the Zn-exposed group for both phases. GnIH was significantly higher in Zn-exposed fish. Serum FSH levels in pre-ovulatory and LH levels in ovulatory fish decreased gradually with an increase in the duration of exposure. Zn exposure reduced vitellogenin (Vtg) and estradiol (E2) in the liver and ovary with an increase in duration from both phases. Ovary maturation-inducing hormone (MIH) levels showed a decrease with exposure duration in ovulatory fish. Moreover, Zn-exposed ovulatory fish showed a degenerated oocyte nucleus due to the disintegration of the nuclear membrane. It might be inferred that Zn altered the HPGL regulatory system of M. vittatus reproduction at both the pre-ovulatory and ovulatory phases.

Estimating the growth parameters, exploitation rate, biomass and maximum sustainable yield of long whisker catfish Mystus gulio (Hamilton, 1822) in the coastal waters from southwestern Bangladesh

The research provides a comprehensive analysis of Mystus gulio including growth pattern, growth parameters, recruitment patterns, mortality rates, biomass, exploitation rate (E), and the estimation of maximum sustainable yield (MSY) within the southwestern coastal waters of Bangladesh. From January to December 2017, fishers provided around 1200 specimens. FAO-ICLARM Stock Assessment Tool and Excel-add-in-solver were used to assess stock status through length-frequency data. Indeed, the research findings indicated that the population of M. gulio displayed negative allometric for both individuals (b = 2.53 for male, b = 2.50 for female), as demonstrated by the calculated allometric coefficient value. Nonetheless, the population's dynamic characteristics revealed an asymptotic length (L∞) of 19.34 cm, 23.28 cm and growth coefficient (K) 0.94 year−1 and 0.81 year−1 for male and female M. gulio. The growth performance indexes (Ø') of 2.55 and 2.64 for male and female and maximum lifespan (tmax) 3.20 years and 3.70 years respectively. This study revealed that the slightly variations in the natural mortality rate (M) for both specimens at 1.55 year−1 and 1.59 year−1. The fishing mortality rate (F) 2.75 year−1 and 1.98 year−1and total mortality rate (Z) 4.30 year−1 and 3.57 year−1 for male and females, respectively. The maximum permissible exploitation rate (Emax = 0.421) was lower than the actual exploitation rate (E = 0.63). The MSY was calculated at 67.968 metric tons. Without a doubt, overfishing stands out as the most critical threat to the wild stock. Therefore, it is clear that the existing fishing approach was not efficiently managed the standing stock in a sustainable manner. The findings would be useful for established proper fishing regulations in coastal waters and the surrounding ecosystems.

Recycling of animal protein wastes in the formulation of feed for Labeo rohita and Mystus vittatus—a comparative evaluation

Lactic acid bacteria (LAB) are key players in the fermentation of organic wastes and their recycling as feedstuff for fish. Whey, a common dairy byproduct in India, is a cheap source of LAB and can be used to ferment animal byproducts. An experimental study was designed to explore whether the whey fermented animal protein blend (WFAPB) could be used as a fishmeal replacer in the formulation of feed for both stomach-less carp fish Labeo rohita and stomach-bearing catfish Mystus vittatus. Experiments were performed with five isoproteinous, isolipidous, and isoenergetic feeds with WFAPB replacing fishmeal (FM) by 0% (T1), 25% (T2), 50% (T3), 75% (T4), and 100% (T5). Fifteen days of laboratory experiments with these experimental feeds revealed that more than 50% FM replacement level could result in excess postprandial absorption (6 h) of some essential and non-essential amino acids in the plasma of both fish. The postprandial absorption was more in M. vittatus than L. rohita. Ninety-day experiments were conducted in outdoor cement vats to measure growths and deposition of amino acids (AA) in muscle. Regression analysis was performed to find the optimal FM replacement based on four growth parameters and fifteen AA deposition in muscle. A two-phase fuzzy methodology was used to obtain Pareto-optimal replacement levels for each fish. The results demonstrated that FM replacement levels were 7.63% and 36.79% respectively for L. rohita and M. vittatus when only four growth parameters were considered. However, based on the FM replacement level that maximized deposition of 15 amino acids and growth parameters, it was found that 12.23% and 40.02% replacement of FM by the WFAPB was ideal respectively for L. rohita and M. vittatus. The results revealed that only a fraction of both essential and non-essential amino acids absorbed in plasma could be converted into protein and deposited as bound amino acids in the muscle. It is concluded that fermentation by whey is an inexpensive, easily available, and environmentally sustainable technique to recycle animal protein in the formulation of feed for fish, and the stomach-bearing carnivorous fish are more efficient in utilizing fermented animal protein blend than the stomach-less carps.

Sweet orange peel waste as a feed additive in growth promoting and protective effect against Aeromonas hydrophila of juvenile bagrid catfish Mystus nemurus

Sweet orange Citrus sinensis peel is a phytobiotic agricultural waste with bioactive compounds that have potential functional properties as a growth promoter and immune stimulator. This study aims to evaluate the dietary effects of sweet orange peel (SOP) as a feed additive on growth enhancement of juvenile bagrid catfish Mystus nemurus and their disease resistance ability against Aeromonas hydrophila infection. Four experimental diets were formulated to contain 0 (SOP0, control), 4 (SOP4), 8 (SOP8) and 12 g/kg (SOP12) SOP. After 90 d of the feeding experiment, improvement in weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio were observed in the fish fed with SOP4. While fish survival was not significantly affected, hepatosomatic and viscerosomatic indices were significantly higher in fish fed with SOP12. Muscle protein was higher in fish fed with SOP4, SOP8, and SOP12 than in control but muscle lipids showed an opposite trend. A 14-d post-challenge test against A. hydrophila revealed no significant effect on the fish survival. Nevertheless, fish fed SOP4 encountered delayed bacterial infection compared to other treatments and fish fed with SOP0 and SOP4 performed numerically better survival. Infected fish showed skin depigmentation, haemorrhagic signs at the abdomen and anus, internal bleeding, and stomach and intestine enlargement. In conclusion, SOP4 could be recommended as a growth promoter while slightly delaying A. hydrophila infection in M. nemurus.

Ecotoxicological insights: Effects of pesticides on ionic metabolism regulation in freshwater catfish, Mystus keletius

Fish maintain their body fluid ionic and osmotic homeostasis using sophisticated iono-/osmoregulation mechanisms through gills ionocytes. Pesticide-induced ionic imbalance in fish has been recognized as a valuable tool to determine its toxic effects. Acute exposure to synthetic and organo-chemical pesticides on the regulation of ionic (Na+, Ca2+, P) metabolism in freshwater catfish Mystus keletius was evaluated. Fish were exposed to sub-lethal concentrations (mg/l) of selected pesticide for a period of 7, 14, 21 and 28 days. Results indicated that chemical pesticides - Impala and Ekalux - evoked adverse toxic effects on selected tissues compared to organo-chemical pesticide tested. Statistical analysis of the summative data using two-way ANOVA was significant (p-value<0.001). Variations in the cellular parameters analysed were attributed to the physiological acclimatization of fish to the pesticide exposed. Based on the results it is concluded that organic pesticides may be preferred for rice field application considering safety aspects.

Age and growth of gangatic Mystus: Mystus cavasius (Hamilton-Buchanan, 1822) by length-frequency analysis from central Brahmaputra Valley, Assam

The Gangatic catfish Mystus cavasius is a native catfish found in Brahmaputra and Barak valley of Assam which is a very popular food fish with has high market price. Our study provides the first data on age and growth of this species in central Brahmaputra valley of Assam. A total number of 285 specimens comprising of 103 males and 182 females have been studied using von Bertalanffy growth model and computer-based FiSAT programme was used for the estimation of growth parameters. In the FiSAT programme, the direct fit of length–frequency data such as Electronic Length Frequency Analysis-I (ELEFAN)-I technique, Shepherd’s method and Powell–Wetherall plot were employed in the present study. The Asymptotic length (L∞) and growth co-efficient (K) (annual) values of Mystus cavasius estimated by ELEFAN I, Shepherd’s method and Powell and Wetherall method. The value of L∞ and K by ELEFAN I, Shepherd’s method and Powell and Wetherall method are 217.0 mm and 0.8 year-1, 215.25 mm and 0.79 year-1 and 220.73 mm and 0.94 year-1 respectively. The two values of Mystus cavasius estimated about -0.41. The total length attained by this fish is about 135 mm at the end of 1st year, 180 mm at the end of 2nd years, 201 mm at the end of 3rd year and 210 mm at the end of 4th year.

Comparative account of blood metabolic and hematological adaptations in air-breathing catfish, Clarias batrachus and non air-breathing catfish Mystus seenghala in the conditions of hypoxia

Comparative account of blood metabolic and hematological adaptations in air-breathing catfish, Clarias batrachus and non air-breathing catfish Mystus seenghala in the conditions of hypoxia

Ecotoxicological Effects of Pesticides on Hematological Parameters and Oxidative Enzymes in Freshwater Catfish, Mystus keletius

Hematological parameters and changes in stress-induced functionalities of cellular enzymes have been recognized as valuable tools for monitoring fish health and determining the toxic effects of pesticides. The present study was conducted to evaluate the toxic effect of selected pesticides viz., Ekalux (EC-25%), Impala (EC-55%), and Neemstar (EC-15%) on freshwater catfish Mystus keletius. Fish were exposed to sub-lethal concentrations (mg/L) of the selected pesticide for a period of 7, 14, 21, and 28 days. Hematological parameters viz., total erythrocyte (RBC), hemoglobin (Hb), and hematocrit (Ht) packed cell volume values decreased with an increase in exposure time to pesticides, whereas the values for parameters viz., leucocytes (WBC), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) increased significantly. A decrease in packed cell volume (PCV) and hemoglobin values coupled with decreased and deformed erythrocytes as signs of anemia were also observed. The effect of pesticides on RBC content was 1.43 (million/mm3) on day 7 and reduced to 1.18 (million/mm3) on days 14 and 21. A similar trend was found for Impala on RBC, which had an initial value of 1.36 (million/mm3) on day 7 and reached a value of 1.10 (million/mm3) on day 28. In contrast, the value of Neemstar decreased from 1.59 (million/mm3) on day 7 in control to 1.02 (million/mm3) on day 28. Data indicates that the order of toxic effect of pesticides recorded a maximum for Impala followed by Ekalux and Neemstar in the selected fish model. Likewise, the overall pattern of pesticidal activity on cellular enzymes (GDH, MDH, and SDH) recorded a maximum toxic effect for Impala followed by Ekalux and Neemstar. Results indicate that Chlorpyrifos pesticide-Impala evoked maximum toxic effect on selected tissues compared to the other two pesticides tested. Statistical analysis of the summative data using two way ANOVA was statistically significant (p-value &lt; 0.001). The differences in the hematological parameters analyzed are attributed to the physiological acclimatization of the fish to the local conditions, which influences the energy metabolism and consequently determines the health status of the fish. Overall, Impala exhibited the highest pesticidal activity on cellular enzyme, followed by Ekalux and Neemstar. Results suggest that natural pesticides may be preferable for rice field application in terms of environmental safety.

The reproductive biology of Mystus mysticetus Robert, 1992 in the Mekong Delta, Vietnam

This investigation aims to study the reproductive traits, including sex ratio, spawning season and pattern, batch fecundity (F), and length at first maturity (Lm), of the commercial catfish Mystus mysticetus living in the freshwater of the Mekong and Chao Phraya basins. A collection of 596 individuals was caught using trawl nets from Cai Rang, Can Tho (CT) and Long Phu, Soc Trang (ST) from October 2020 to September 2021. The results showed a female-biased sex ratio (0.64 males: 1.00 females) and a pattern of multi-spawner as ripe ovaries contained different developmental stages of oocytes. A combined analysis of gonadal occurrence frequency and gonadosomatic index showed that this fish spawned during the wet season with a peak in June-July at CT and September-October at ST. The F ranged from 4,470–22,457 eggs/female (CT) to 4,104–23,651 eggs/female (ST) and these values increased with fish size. The egg diameter ranged from 0.63 ± 0.06 to 0.64 ± 0.06 SD mm, and Lm was higher in males (11.6 at CT and 11.2 at ST) than in females (10.9 at CT and 10.4 at ST). To conclude, it is recommended that the fish should be caught at length > Lm and avoid fishing in the main spawning period in order to exploit this fish resource sustainably.

Dichlorodiphenyltrichloroethane (DDT) residues status in fishes and prawns of Chittagong chemical complex area, Bangladesh

Fourteen various fish samples i.e., rui Labeo rohita, catla Gibelion catla, striped dwarf catfish Mystus vittatus, stinging catfish Heteropneustes fossilis, walking catfish Clarias batrachus, Ganges river sprat Corica soborna, mola carplet Amblypharyngodon mola, common carp Cyprinus carpio, Nile tilapia Oreochromis niloticus, climbing perch Anabas testudineus, spotted snakehead Channa punctatus, striped snakehead Channa striata, bronze featherback Notopterus notopterus, wallago catfish Wallago attu and mixed juvenile prawns were collected from a pond of closed down DDT (Dichlorodiphenyltrichloroethane) factory area of Chittagong Chemical Complex (CCC) of Bangladesh to assess the concentrations of DDT and its metabolites (4,4'-DDD and 4,4'-DDE). The fish flesh and shell-free prawn muscle samples were extracted by QuEChERS method and these were cleaned up using H2SO4. The cleaned sample extracts were analyzed using a Gas Chromatograph coupled with Electron Capture Detector (GC-ECD). The cultured L. rohita was used as a control which was found to contain no detectable amount of DDTs. Recovery experiments with control samples were spiked with certified DDTs standard at three different concentrations (0.01 mg kg-1, 0.02 mg kg-1 and 0.05 mg kg-1) levels. The percent recoveries were 72-114 % (0.05 mg kg-1), 70-101 % (0.01 mg kg-1) and 87-105 % (0.02 mg kg-1). LOD and LOQ of the standards were found to be 0.0625 μg kg-1 and 0.2063 μg kg-1, respectively and R2 of 4'-DDE, 4,4'-DDD, 2,4'-DDT and 4,4'-DDT were found to be 0.999, 0.999, 0.999 and 0.998, respectively. The concentrations of total DDTs residue in fish and prawn samples ranged between 0.66 ng g-1 in W. attu to 8.90 ng g-1 in H. fossilis. The ratios of 4,4'-DDT/ΣDDTs in the studied fish samples indicated the historical use of DDTs in the adjacent region around the DDT factory of the CCC area. The concentrations of total DDTs in all the samples were within the permissible Maximum Residue Level (MRL) recommended by FAO-WHO. To assess human health risks, Health risk Indexes (HI) of fish and prawn samples were calculated. HIs&lt;1 in all fish and prawn samples indicated that the fish samples are safe to consume but the daily consumption of the fish together with other contaminated food may cause human health hazards. Bangladesh J. Zool. 49 (3): 381-391, 2021

Fish diversity and assemblage structure along the river-estuary continuum in the River Cauvery, India

Abstract A comprehensive study on the fish assemblages of the River Cauvery was conducted during 2017–2020 by structured fish sampling surveys, encompassing various sampling sites situated along the upper, middle, lower, and estuarine stretches. The present study recorded a total of 146 fish species belonging to 52 families from the River Cauvery. The highest recorded fish diversity was at Hogenakkal (76 species) as it is situated in the transition zone between Deccan Plateau and the plains of Tamil Nadu. Lowest diversity was recorded at Bhagamandala (23 species), as this site represented a narrow hillstream habitat. As per SIMPER analysis, the silver razor-belly minnow (Salmostoma acinaces) was the most representative species in Upper Cauvery, with percentage similarity contribution (% SC) of 36.55%. The Middle Cauvery situated in the plateau zone was mainly represented by Labeo calbasu (14.01% SC), the exotic Nile tilapia (Oreochromis niloticus) with 8.45%, and the bagrid catfish Mystus cavasius (5.1%). The exotic species contributed to maximum fish catch and gradually replaced the native fish fauna in Lower Cauvery. The fish fauna of Cauvery Estuary is distinct from other zones with a characteristic fish assemblage represented by the glassy perchlet, Ambassis miops (11.97% SC), Crenimugil buchanani (11.14 %), and Mugil cephalus (6.23 %). Among the fish species recorded during the present study, 29 species were endemic to Western Ghats, of which 10 species were categorized as threatened by the IUCN, including 2 critically endangered (Barbodes bovanicus, and Hemibagrus punctatus), 5 endangered (Dawkinsia arulius, Hypselobarbus curmuca, H. mussullah, H. micropogon, and Nemacheilus pulchellus) and 3 vulnerable species (Hypselobarbus kolus, Hyporhamphus xanthopterus, and Wallago attu). A holistic study on the fish communities of Cauvery along the spatio-temporal scale is imperative to ensure sustainable management for conservation of endemic fish fauna.

SEASONAL CHANGES OF CHOLESTEROL IN THE TISSUES OF MALE CATFISH MYSTUS CAVASIUS (HAM) IN BHADRA RESERVOIR, KARNATAKA, INDIA

Seasonal variation in cholesterol of the different tissues of the freshwater catfish Mystus cavasius was investigated from Bhadra Reservoir. The amount of cholesterol in liver, muscle and testes was measured. A decline was recorded during the period when the gonads were passing through the peak ripe stage. The highest value of the cholesterol was however attained before this phase of gonad maturation. Concentration pattern of liver cholesterol seemed related to variations in the cholesterol metabolism of the fish, necessitated, besides other factors, by the demand for sex hormones. A possibility of the influence of feeding intensity on liver cholesterol content has also been indicated.

Hematological, Biochemical and Immunological Responses of Estuarine Catfish Mystus gulio (Hamilton 1822) After Exposure to Lead (Pb)

Due to increased industrialization in developing countries some of the toxic substances are being increased in day-to-day life. Living organisms need some trace amounts of metals like copper, manganese, zinc etc. but some of the non-essential toxic heavy metals are also accumulated in the body of living organisms which may cause damages to the immune organs of the organism. The present study investigated the impacts of sublethal dosage of inorganic Lead acetate on the hematological, biochemical and immunological responses of the brackish water fish Mystus gulio. The LC50 at 96 h was determined by the Probit method. The experiment was performed for 30 days of exposure of lead acetate (4 mg/l) to the fish Mystus gulio. After exposure to lead nitrate hematological (hemoglobin, RBC, WBC, PCV, neutrophil, eosinophil and platelet), biochemical (glucose, protein, albumin and globulin) and immunological (IgM) parameters were analyzed. A decrease was seen in the RBC count, hemoglobin, PCV, MCV, MCH, MCHC, protein, albumin and globulin whereas an increase was seen in WBC count, neutrophils, eosinophils, ESR, platelet count, glucose and Immunoglobulin (IgM).

Suitable Stocking Density Ensures Best Production and Economic Returns in Floating Cage Aquaculture System

The striped dwarf catfish Mystus cavasius being a least concern small indigenous fish it is necessary to protect the species from extinction in the near future. An experiment on production and economic feasibility of Mystus cavasius in cage was conducted for a period of six months from March to August 2020 in beel hilla at Naogaon district of Bangladesh. The study was carried out in nine cages (rectangular 8x5x2 feet size) under three treatments namely T1, T2 and T3 performed with the stocking densities of 46 fry m-2, 92 fry m-2 and 137 fry m-2 and designed each with three replications. The fish was fed with commercial pellet feed (containing 30% crude protein) twice daily at the rate of 5-7% of fish body weight. The total production was found to be significantly (p&lt;0.05) highest in T3 among the three treatments. The net profit was better in T3 than T1 and T2 in terms of better production and money. So, stocking density of Mystus cavasius at the rate of 137 fry m-2 in cage could be an economically feasible aquaculture technique for fish farmers.

Helminth Parasitofauna of Freshwater Catfish MYSTUS SEENGHALA (SYKES 1839) from Nanded District (M.S.) India

Helminth Parasitofauna of Freshwater Catfish MYSTUS SEENGHALA (SYKES 1839) from Nanded District (M.S.) India

Seasonal Dynamics of Stomach Contents, Trophic Level, Length-Weight Relationship and Condition Factor of Mystus bleekeri (Day, 1877)

The Asian catfish Mystus bleekeri is a popular food fish along with favored as an ornamental fish in Bangladesh. Till now detailed report on stomach contents, trophic level, length-weight relationship and condition factor of this fish species in the agro-climatic context of Bangladesh is lacking. Hence, the aims of this study were to describe the stomach content, trophic level, length-weight relationship (LWR) and condition factors of Mystus bleekeri collected from Dekhar Haor, Sylhet, Bangladesh from July 2017 to June 2018. A total of 600 specimens ranging from 6.9-24.6 cm total length (TL) and 5.7-72.4 g body weight (BW) was analyzed in this study. Stomach content analysis showed that the fish fed mostly on Mollusca with a frequency of occurrence (fo: 25.36%) and worms (fo: 21.68%), followed by plant matters (fo: 3.32%), Cladocerana (fo: 1.18%), Copepoda (fo: 0.95%), and Teleostei (fo: 0.36%). The estimated mean trophic level (TROPH) ranged from 2.35±0.13 in December to 3.02±0.23 in August, indicating that they are opportunistic feeder. The LWR analysis showed negative allometric growth (b&lt;3) throughout the year. The values of the exponent b in the LWR (W=aLb) vary between 1.474 and 2.490.The mean K value was significantly higher in October indicating the heavier weight and better condition of the fish (P&lt;0.05). The data obtained from this study would be useful to introduce sustainable management of Mystus bleekeri not only in Dekhar Haor but also in other inland waters of Bangladesh.

On a new Monogenean-ectoparasites Neocalceostoma guptai n. sp. from gills of fresh-water cat fish Mystus seenghala (Ham.) of District Ayodhya (Faizabad), Uttar Pradesh, India

The fresh-water cat fish Mystus seenghala (Ham.) was collected from local fish market of district Faizabad presently known as Ayodhya (U.P.) and examined 25 specimens, of which only 02 specimens were found infected with 08 specimens of said species. The sites of infections being gill filaments of the host. There are three species of the genus Neocalceostomawas discovered earlier viz.Neocalceostoma elongatum; Neocalceostoma microformis and Neocalceostoma chauhani. The present form differs from all the known species. It differs from Neocalceostoma microformis and Neocalceostoma chauhani in having larger body, difference in ratio of haptor and body, difference in shape of cirrus and gonads. The present form also differs from Neocalceostoma elongatum in having different shape of haptor, absence of oesophagus and difference in shape of cirrus. The present form is therefore, described as a new species Neocalceostoma guptai n. sp. named in honor of Dr. S. P. Gupta for his valuable contribution in the field of taxonomy

EVALUATION OF MEDIAN LETHAL CONCENTRATION (LC ) 50 OF MYSTUS VITTATUS (BLOCH) FOR COPPER SULPHATE

The toxic effect of Copper on freshwater catfish Mystus vittatus was studied. The LC values of copper in Mystus 50 vittatus for 24, 48, 72 and 96 hours were 20.589, 16.497, 11.815 and 8.665 mg/L respectively. The cat fish was silvery grey in body in the control group throughout the experiment. The body colour changed from original silvery grey to dark colour in heavy metal treated fish. The fish maintained in freshwater behaved normal as usual. But when the fish was exposed to copper, erratic swimming, abnormal posture, dis-balance, sluggishness, imbalance in posture, increase in surface activity, opercular beating, and gradual loss of equilibrium and spreading of excess of mucus all over the surface of the body were observed.

Sublethal effects of phenol on histology of selected organs of freshwater fish Mystus vittatus.

Acute toxicity (96 h LC50) of phenol was analyzed in the cat fish Mystus vittatus in static bio-assay over a 96-h exposure period using probit method. The 24, 48, 72, and 96 h LC50 values (with 95% confidence limits) of phenol for fingerling catfish were found out as 13.98, 13.17, 12.62, and 12.21 mg/l respectively. Investigations pertaining to the histopathological sections have shown high degree of pathological lesions observed in various parts like gill, liver intestine, and kidney of the fish species. Analysis of gill section revealed observable changes in the experimental species such as fusion, malformation at the tip of secondary lamellae, vacuolation, hyperplasia, and epithelial damage. Exposure of phenol showed cytoplasmic vacuolation, tissue damage, and loss of hepatic cell wall in the liver of experimental organism. Lesions of tissue damage at the epithelial site, inflammation, and clumping of adjacent villi made of columnar epithelium have been observed in the intestine of fish, and also the excretory part of the fish kidney revealed various changes like glomerular atrophy, damage of Bowman's capsule, vacuolization, and degeneration of renal epithelium. The current study on histological changes observed in the experimental organisms has thrown light on the current scenario which poses threat and danger to the whole aquatic ecosystem, and this study plays a vital role in assessing the aquatic pollution.