Cirrhinus Mrigala Research Articles

Evaluation of stocking density for pond aquaculture with special reference to survival and production in Tiruchirapalli, Tamil Nadu

The present study was conducted to optimize the stocking density for pond fish culture. For this purpose, two different stoking densities, i.e. 18000 (T1) and 7600 per hectare (T2) were tested using earthen ponds of 0.25 ha size. Both ponds were stocked uniformly with 4 carp species, viz. Catla catla, Labeo rohita, Cirrhinus mrigala, and Cyprinus carpio in equal proportions and fed on commercial pellet feed (20% crude protein). The estimated gross production was found higher in pond T2 (4166 kg/ha) than that of T1 (4000 kg/ha). The T2 pond showed a net estimated additional yield of 187.76 kg/ha, which was 4.74% higher than that of T1 pond. A higher survival rate was observed in T2 (59.17%) than that of T1 (27.68%), which was statically significant. Further, the ADG (average daily growth) rate of fishes in T2 was 0.70 kg/ha/day higher than that of T1. The study revealed that there is an inverse relation between the stocking density of fishes and production rate. Considering the growth/production rate and survival in present study, a seed stocking density of 7600 per ha is recommended for farm pond aquaculture.

Rice farming components for biological weed control in transplanted rice: perspective on weedy rice management

AbstractFarming elements other than the crop, when integrated into the system, are supplementary, with multifold uses that include weed and pest management. Elements such as fish and poultry birds are integrated with transplanted wetland rice (Oryza sativa L.) for ensuring farmers’ livelihoods and the nutritional security and sustainability of the system. Integrated animal components such as poultry birds and fish also supplement the system with weed control. The role and efficacy of these animal components as tools for managing weedy rice (Oryza sativa L.) were explored, as weedy rice infestation is increasing. This threat of weedy rice is due to scarcity of water resulting from poor water management and improper field leveling. Grass carp (Ctenopharyngodon idella val.) produced the highest reduction of weedy rice biomass, 28% within 24 h under laboratory conditions. Polyculture of C. idella, mrigal (Cirrhinus mrigala Ham.), and silver carp (Hypophthalmichthys molitrix val.) reduced the biomass of weedy rice by 21% within 24 h. In laboratory studies, poultry manure at the highest concentration of 5% reduced the weedy rice seed germination 100% compared with rice seed germination at 91%. This conformed with microplot experiments in which poultry manure at 15.6 g d−1 resulted in a weed control index (WCI) of 8% in both years. However, poultry manure at 15.6 g d−1 in combination with herbicide application resulted in the highest control indices of weedy rice: 52% in 2017 and 2018. Integrating fish and poultry with PRE application of oxyfluorfen (0.25 kg ha−1) resulted in the highest WCI and grain yield in field experiments.

The occurrence of known Myxobolus and Thelohanellus species (Myxozoa, Myxosporea) from Indian major carps with the description of Myxobolus bandyopadhyayi n. sp. in West Bengal.

Myxosporean infection of Indian major carps (rohu, Labeo rohita; catla, Gibelion catla; mrigal, Cirrhinus mrigala) was examined from two fish farms and two fish markets in West Bengal, India. One Thelohanellus and four Myxobolus species were detected from the fins and scales of the investigated species. Comprehensive morphological and molecular biological studies revealed four already known species, Thelohanellus caudatus from the fins of rohu, Myxobolus dermiscalis from the scales of rohu, Myxobolus chakravartyi from the fins of catla, and Myxobolus rewensis from the fins of mrigal. This study complemented the species description of M. chakravartyi and M. rewensis with the missing molecular data. Moreover, based on morphometrics and ssrDNA sequence data, a new species was documented from the scales of rohu, and named Myxobolus bandyopadhyayi n. sp.

Enhancing adaptive capacity of wetland fishers through pen culture in the face of changing climate: A study from a tropical wetland, India

Abstract Wetlands are among the most productive of all aquatic ecosystems. In developing countries, millions of marginal fishers rely solely on wetlands for security of both nutrition and livelihood. The decline in wetland fisheries owing to anthropogenic and climatic changes has made fishers increasingly vulnerable. Pen culture can be an effective climate-resilient technology for enhancing fish production in shallow, macrophyte-choked, and multi-stake floodplain wetlands, especially in eastern and north-eastern India. In this context, pen culture was implemented as an adaptive measure in a tropical Gangetic wetland (Mathura) to enhance fish production and increase the adaptive capacity of fishers. Indian Major Carps, Gibelion catla, Labeo rohita, and Cirrhinus mrigala of initial size 10.4±.21g, 8.2 ± 0.48g, and 6.5 ± 0.23g respectively, were stocked at the ratio of 4:4:2 and at the rate of 30 fish m-2 each in pens of 100 m2 in duplicate. For purposes of conservation, Labeo bata and Gudusia chapra, 4.3 ± 0.18g and 3.8±.34g initial size, respectively, were stocked at the rate of 20 Nos.m-2 each at the ratio of 1:1. The fish were fed with commercial feed at the rate of 4% of body weight. A net survival of 82%, 87%, and 75% was recorded in Indian Major Carps, L. bata and G. chapra. A production of 380 kg IMC was achieved during 120 days of the culture period. L. bata achieved an average weight of 21.40 ± 0.34g during the 90-day culture period, with a survival rate of 87%. G. chapra attained an average weight of 16.5 ± 0.42g during the culture period, with a recorded survival rate of 75%. G. chapra was observed to spawn in the pen. The water quality inside pens and reference sites did not differ significantly (p >0.05). The produced fish were released in the wetland for fisheries enhancement. The present communication discusses the technological suitability and economic feasibility of adopting climate-resilient pen culture as an adaptation measure for enhancing the adaptive capacity of wetland fishers in the face of a changing climate.

Pattern of spatio-temporal fish diversity in association with habitat gradients in a tropical reservoir, India

Abstract Reservoirs are aquatic resources with the potential to increase India's fish production through inland fisheries. Thippagondanahalli is a medium-size reservoir on Arkavathy River, a tributary of the Cauvery. It is located in Bangalore rural district of Karnataka (12°58’24” to 12°96'49" N 77°20’33” to 77°35’63” E) and has a water surface area of 1162 ha at full reservoir level and 784.55 m at full supply level. Fish diversity studies were conducted to examine the spatial and temporal variations in fish diversity in relation to habitat parameters. A taxonomic abundance of 25 fish species (80% of them native) belonging to 14 families and 4 orders was recorded. A range of statistical estimators such as Chao 1, Jack 1, and Bootstrap were used to assess the expected species richness. The Jack 1 method showed the highest abundance with 28 species. The littoral zone, dominated by small indigenous species, was found to have relatively higher fish diversity (Shannon index-1.86) compared to the limnetic zone of the reservoir. Shannon diversity was higher in the monsoon season (1.76) compared to other seasons. Physico-chemical parameters revealed that this waterbody is highly eutrophic. Canonical correspondence analysis between seasonal habitat characteristics and seasonal species abundance showed the abundance of the small indigenous fish Amblypharyngodon mola during the post-monsoon season, the bottom feeder Cirrhinus mrigala and the surface feeder Rasbora daniconius during the monsoon season, and the carnivores Mystus malabaricus and Channa orientalis as well as the planktivore Puntius sarana during the pre-monsoon season. This study suggests the use of fisheries management and conservation measures such as fish-aggregating devices, stocking of certified seed, and impact assessment of exotic species.

Impact of inclusion of hybrid red tilapia (Oreochromis mossambicus × O. niloticus), on total production in farm pond aquaculture

The present study was conducted to evaluate the impact of inclusion of hybrid red tilapia (Oreochromis mossambicus × O. niloticus) on productivity in carp based pond aquaculture. An experiment for a period of 270 days was conducted in two sets of earthen ponds (each of 0.132 ha size with 1.5 m depth). In Set I, five species viz. Catla catla, Labeo rohita, Cirrhinus mrigala, Ctenopharyngodon idella and Cyprinus carpio) were stocked (@13636 ha-1) in a respective ratio of 1:1:1:1:2. In Set II, hybrid red tilapia was included as additional species to other five carp species and stocked @ 13636 ha-1 in equal numbers. The seeds stocked (initial size 5-6 cm) were fed on commercial pellet feed having 20% protein, by broadcasting over the pond surface. The water quality parameters viz., temperature, pH, dissolved oxygen, alkalinity, nitrogen, phosphate and potassium remained more or less same in both the sets of experimental ponds. However fish growth parameters significantly differed in both the sets of experiments. Highest production of 2575.79±107.08 kg ha-1 was recorded in Set II followed by Set I with a production of 1894.32±428.44 kg ha-1. Tilapia stocked as an additional species provided a net estimated additional yield of 680.64 kg ha-1, which was 36.47% higher than that of Set I. The results of this study have proved significant impact of hybrid red tilapia inclusion on enhancing the net productivity. Keywords: Additional species, Farm ponds, Productivity, Red tilapia, Stocking density, Yield enhancement

Effect of Sub Lethal Doses of Nickel Chloride on CBC and Histology of Cirrhinus Mrigala

This present study aims to investigate the histological and CBC parameters on Cirrhinus marigala after the exposure of Nickel Chloride. The first group of fish was taken as control group and placed in normal water without given any treatment. The second and third groups of fish were administered to two concentrations of sub-lethal doses of 96 hrs (LC50, 3.75ppm) of nickel chloride for 30 days. Results of this study showed that the number of white blood cells, platelets and haemoglobin level were significantly increased where simultaneously the number of red blood cells was significantly decreased due to exposure of nickel chloride. It was also observed that nickel chloride accumulated in organs (Kidneys < Gills < Liver < Heart) of Cirrhinus marigala. Results of histopathology showed the heavy damage of vital organs in fish due to nickel chloride exposure. One-way ANOVA test was performed in SPSS package volume 16 showed that observed data was statistically signi?cant (P < 0.05). This study concluded that nickel chloride effects the CBCs and histopathological parameters of fish Cirrhinus marigala. Keywords: Fish, Toxic effect, Heavy metal, blood parameters

Isolation of Lactic Acid Bacteria from Intestine of Freshwater Fishes and Elucidation of Probiotic Potential for Aquaculture Application.

Probiotics play significant roles in enhancing systemic immunity, improving intestinal balance and feed value, enhancing enzymatic digestion, and inhibiting pathogenic microorganisms of freshwater fish. Probiotics from an identical organism's gastrointestinal system promote effective colonization and provide greater benefits than other sources. This study aimed to evaluate the usefulness of probiotic bacteria isolated from the intestines of freshwater fishes for a dietary supplement of freshwater aquaculture. A total of 120 isolates were collected from freshwater fishes of Channa striata, Puntius filamentosus, Oreochromis mossambicus, Cirrhinus mrigala, and Rasbora daniconius. Seven of these isolates exhibited antagonistic activity against fish pathogens: Aeromonas hydrophila, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa. Using 16S rRNA gene sequencing analysis, the isolates were identified as Enterococcus sp., Lactococcus lactis, Weissella cibaria, and Limosilactobacillus fermentum. Of these tolerates, L. fermentum URLP18 isolated from C. mrigala exhibited high tolerance to low acidic (pH 2.0) and high bile salt (2%) concentrations, exhibiting a significant hydrophobicity and extracellular enzyme secretions like amylase, protease, and lipase. In vitro evaluations on intestinal mucus indicate that L. fermentum URLP18 have strong adherence capacity, and its survival rate increased after being administered to Artemia nauplii. The results suggest that L. fermentum URLP18 has high probiotic potential and is an effective dietary supplement for freshwater aquaculture.

Cerium oxide nanoparticles induced physio-biochemical, neurochemical, and morphological responses in Cirrhinus mrigala during short term exposure

Cerium oxide nanoparticle (CeO2NPs) has wide applications in pharmaceutical, biomedical and chemical industries. Albeit of their uses, bioavailability followed by toxicity of CeO2NPs in fresh water fishes, are yet to be understood in detail. In this evaluation, we have synthesized, characterized and assessed the biological effects (hematology, ionoregulatory, oxidative stress, histological and glutamate indices) of CeO2NPs at different doses (2.5mg/L and 25mg/L based on 1/10th LC50) on freshwater carps Cirrhinus mrigala, for short term exposure of 96 h. Impact of CeO2NPs at low concentration (2.5mg/L) confirmed a significant decrease in hematological parameters and also affecting serum Na+, Cl-, K+ levels along with gill Na+/K+-ATPase activity. The indicated variations oxidative stress enzymes superoxide dismutase, Catalase, glutathione peroxidase with relative elevation in lipid peroxidation (LPO) (22.47±0.198) compared to control groups. CeO2NPs at high concentration (25mg/L) revealed the alterations in neurotransmitter glutamate levels compared to control groups. Rise in glucose and decrease in plasma protein levels in response to both the concentrations was noted. Microscopic observations confirmed the tissue damages and alterations in gill architecture. By integrating all results obtained by short term exposure of juvenile carps to CeO2NPs at different doses, we reported nanoparticles have considerable deleterious effects on physiological and morphological condition of fishes.

Livelihood Patterns and Socio-economic Conditions of the Fishermen of Kharingcha Baor at Chaugachha Upazilla in Jashore District, Bangladesh

A field study was carried out to investigate the livelihood patterns the socio-economic conditions of the small-scale traditional fishermen of Kharingcha baor at Chaugachha upazilla in Jashore, Bangladesh. The survey was conducted on 100 peoples from 70 families of the fishermen in the study area. It was found from the study that 94% fishermen were comprising of males, while 6% were of females. Among them, the majority was Hindus (88%) and the minority was Muslims (12%). During the suvey, the proportion of semi paka houses were documented to be 88%, while kancha were 12%, and all the families had electricity facilities. It was found that 20% of fishermen had no education, 6% had passed SSC-HSC examinations, 14% had passed 6-10 classes and 24% had passed 1-5 classes. It revealed that 84% of fishermen were married and 16% were unmarried. Throughout the study, 33% of the fishermen were found to be dependent on village doctors, 40% on upazilla hospital and 27% on MBBS doctors. Several types of local boats and dingi nouka as well as nets such as tana jal (surrounding net), set bagnet, khapla jal (cast net), thela jal (push net) etc. were used for the harvesting of different fish species (Labeo rohita, Catla catla, Cyprinus carpio, Cirrhinus mrigala, Heteropneustes fossilis, Channa striatus, C. punctatus etc.). Averagely, 35-80 kg fish per day was caught by a group of fishermen using a boat. The majority of the fishers sold their harvested fishes upon the fulfillment of their demands. The monthly mean income of fishermen was around BDT. 5,000-15,000 in the baor area. Among the fishermen, 56% of them were observed to lend money from money lenders and 44% from the NGOs for their fishing-related activities and livelihoods. It revealed from the present findings that the traditional fishermen of Kharingcha baor require more technical, organizational and institutional helps for the improvement of their socioeconomic condition and sustainable livelihood.

Single Genetic Stock Revealed by Microsatellite Markers Among Wild Populations of Cirrhinus mrigala from Peninsular India

Cirrhinus mrigala (mrigal) is one of the Indian major carps widely cultured in the whole Indian subcontinent. Population genetic structure of this species from Peninsular Rivers of India is lacking. Among DNA markers, microsatellites are excellent tools to evaluate genetic variation of populations. In this study, genetic variation of six peninsular riverine mrigal populations was evaluated using seventeen microsatellite loci. In analyzing 288 samples, the number of alleles ranged from 4 to 27; observed heterozygosity from 0.595 to 1.00, expected heterozygosity from 0.586 to 0.959 and inbreeding coefficient (FIS) ranged from -0.034 to 0.02. Exact test for Hardy Weinberg disequilibrium revealed that one locus was not in equilibrium across the rivers except one. The AMOVA analysis revealed the main source of genetic variation to be within the population (94.54%) than among the populations (5.46%). The Nei’s genetic distance and structure analysis depict river Narmada and Mahi populations are different from the four east coast rivers. The overall Fst (0.05462) data showed moderate differentiation among the six populations. The results of this study provide essential information to resource recovery and help in delineating populations for fishery management. Besides, the data will provide a valuable baseline for further investigations on the geographic distribution of this commercially important fish species.

A comparative study of fatty acids profile of two Indian major carps (Gibelion catla, Hamilton, 1822 and Cirrhinus mrigala, Hamilton, 1822) using value added fish feed

Freshwater fishes are not only a major source of protein but they also possess nutritionally valuable lipids in the form of Polyunsaturated fatty acids (PUFAs), which play a crucial role in the normal growth, disease prevention, development, cardiovascular health and reproduction of human. The present study was performed to determine the incorporation rate of fatty acids profile and their composition in two common freshwater carps as Gibelion catla and Cirrhinus mrigala (in situ trial and experimental) in the different experimental time period (0 days, i.e. initial, 90 days and 180 days) by using of value added feed like flaxseed (?-linolenic acids, 51.26% – 54.94%) and soybean oil (?-linolenic acids, 7.95%-9.01%) as omega-3 supplements. To determine the specific growth pattern Length-Weight Relationships (LWRs) are analyzed where it showed positive allometric growth (b=3.20 in 90 days, b=3.11 in 180 days for Catla and b=3.18 in 90 days, b=3.1 in 180 days for Mrigala fish). The Gas Chromatography-Mass Spectrometry (GC/MS) method also confirmed that the percentages of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) increased significantly (P< 0.05) in experimental (0.096a±0.41, initial; 5.16a±0.27, 90 days; 6.21b±0.36, 180 days Catla fish species and 0.019a±0.96 initial; 3.74b±0.37, 90 days; 3.50a±0.46 180 days for Mrigal fish species) fishes rather than controls (4.28a±0.27, 90 days; 4.36b±0.36, 180 days for Catla species and 2.24b±0.31 90 days; 2.50a±0.11 180 days for Mrigal species). Therefore, it was clearly indicated that formulated diet performed significantly to maintain the positive allometric growth as well as successive enrichment of PUFAs in experimental specimens, which is beneficial for human health as high source of protein and PUFAs as well.

Study of parasitic effect of Argulus sp. on Indian major carps in pond culture

The current investigation was undertaken to study the parasitic effects of Argulus sp. on Indian major carps. Only symptomatic and moribund samples of diseased fishes comprised of fingerlings and adults of Labeo rohita, Catla catla and Cirrhinus mrigala were collected for experiments. The affected fishes showed weight loss, retarded growth, restlessness, erratic swimming behaviour and loss of appetite. The skin showed abnormally pigmented while gills, kidney, liver and spleen of the affected fishes were pale in colour. The most significant histopathological lesions in the gills were the secondary lamellar hyperplasia, haemorrhages in the tips of the primary lamellae and fusion of both secondary and primary gill lamellae. Skin showed epidermis was lost but the epidermal cells in the vicinity of the sites of attachment were hyperplastic, muscular layer showed degenerative and necrotic. Kidney showed multifocal enlargement of glomeruli, glomerular tufts in many places shrunken, fragmented and necrosed, in renal tubules vacuolar degeneration. Fingerlings and adults of rohu were found highly susceptible to this disease than other IMC.

Ultrastructural biomarker responses in gill tissues of Cirrhinus mrigala (Hamilton, 1822) through SEM after exposure to zinc sulphate

Zinc is an essential trace element for the normal development and metabolism of living organisms. Mrigal (Cirrhinus mrigala) was exposed to sub-lethal concentrations 9.3, 13.2, 18.6 and 31 mg/l of zinc sulphate for 30 days and ultrastructural alterations were observed in the gills. The gill epithelium of the untreated group showed a normal architecture while zinc- treated groups showed certain marked changes in gill tissues such as fusion of secondary lamellae, edema, disruption of gill epithelium, hypertrophy, hyperplasia, broken and swollen microridges, broken tips and upliftment of gill rakers, heavy exudation of mucous and disorganization of secondary lamellae. These changes demonstrate the morphological responses of the fish when exposed to zinc sulphate. The present study clearly shows that gills are an important target organ for zinc toxicity in C. mrigala.

Surveillance of Escherichia coli in a fish farm of Sylhet, Bangladesh

The study was accomplished to investigate Escherichia coli from two freshwater fish, Tilapia (Oreochromis niloticus) and Mrigal (Cirrhinus mrigala), collected from a fish farm in Sylhet, Bangladesh. Six of each fish were analyzed to isolate and detect Escherichia coli, and E. coli was identified based on morphological and biochemical characteristics. The antibiogram of E. coli was investigated in different generations using eight antibiotic discs such as Chloramphenicol (CH), Streptomycin (S), Gentamycin (G), Ciprofloxacin (CI), Co-trimethoxazole (CO), Azithromycin (AZI), Erythromycin (E) and Novobiocin (NV), and the sensitivity of E. coli was found as 100%, 25%, 100%, 75%, 87.5%, 81.25%, 0%, 0% respectively. Among the 8 antibiotics, for Erythromycin (E) and Novobiocin (NV), the observed resistance pattern of E. coli was 81.25% and 87.5% respectively, whereas, for the rest of the antibiotics, it was 0%.
 Bangladesh J. Zool. 48(2): 335-346, 2020

Compensatory growth response of Catla catla (Hamilton, 1822) juveniles, stunted with varied stocking density and photoperiod, in subsequent grow-out phase

Stunted juveniles of Catla catla (Hamilton, 1822) were produced through 150 days of stunting with five combinations of density and photoperiod. These stunted juveniles were subsequently polycultured in grow-out ponds for eight months along with rohu (Labeo rohita) and mrigal (Cirrhinus mrigala). In grow-out trial, the five treatments with different combinations of stocking density and photoperiod comprised, control (20 m-3, 12L/12D), T-1 (30 m-3, 12L/12D), T-2 (40 m-3, 12L/12D), T-3 (20 m-3, 6L/18D) and T-4 (20 m-3, 0L/24D). After eight months of culture, growth curves of stunted catla in all treatments were non-convergent and inferior to control, indicating no compensatory growth response. Although survival (70-73%), average body weight, (ABW; 667-755 g) and weight gain (648-729 g) in grow-out phase were statistically similar in the groups with different stocking density (Control, T-1 and T-2) (p>0.05), the grow-out survival was relatively higher in T-2 (73.3%), indicating its positive correlation with higher stunting density. In contrast, juveniles stunted with reduced photoperiod (T-3 and T-4) showed significantly lower ABW and weight gain (p<0.05). The poor survival in T-3 and T-4 (40-43%) indicated significant effect of stunting with reduced photoperiod on subsequent grow-out survival and yield performance. Based on the results, the study recommend the use of rearing density up to 40 m-3 for juvenile stunting in catla.

Antioxidant properties of papain mediated protein hydrolysates from fresh water carps (Catla catla, Labeo rohita and Cirrhinus mrigala) and its application on inhibition of lipid oxidation in oil sardine mince during ice storage.

Fish protein hydrolysates (FPH) from fresh water carps Catla catla, Labeo rohita and Cirrhinus mrigala were prepared with 5, 10, 15 and 20% degree of hydrolysis (DH) using papain enzyme. FPH were evaluated for antioxidant properties using in vitro assays such as DPPH free radical scavenging activity (at 10mg/ml), ferric reducing antioxidant power assay (at 20mg/ml) and linoleic acid peroxidation inhibition activity (at 10mg/ml). Antioxidant properties of FPH varied with species and DH. The DPPH radical scavenging activity, linoleic acid peroxidation inhibition activity and ferric reducing antioxidant power (as absorbance at 700nm) of FPH from carps was in the range of 59-92%, 52-85% and 0.388-0.663 respectively. Based on the overall antioxidant activity, FPH from C. catla with 20% DH was added to oil sardine mince at different concentration (0.1, 0.2 and 0.4%) and found to inhibit effectively the formation of peroxides and malonaldehyde in dose dependent manner. FPH from C. catla with 20% DH was fractionated using size exclusion chromatography and had three different peptide fractions with the approximate molecular weight of 6561-2106Da (fraction 1), 1942-994Da (fraction 2) and 935-383Da (fraction 3). The present study showed promising results that the fish protein hydrolysates from fresh water carps muscle proteins can be used as natural antioxidants in food system. Production of fish protein hydrolysates with nutraceutical properties could be the way forward for better utilization and value addition.

Behaviour and morphology pattern analysis of Indian major carps fingerlings exposed to commercial diesel oil suspension

ABSTRACT Increased demand for commercial petroleum derivatives, including diesel has increased the possibility of numerous spills and leakages into the aquatic environment worldwide that can directly or indirectly pollute waterbody disrupting the health status of fish species and other aquatic organisms. This study was conducted to understand the effects of commercial diesel oil on freshwater species of rui (Labeo rohita), catla (Catla catla), and mrigal (Cirrhinus mrigala) fingerlings. The fingerlings were exposed to four different concentrations (0; 0.25; 0.50 and 0.75 ppm) of diesel oil, each containing three replications for 96 h. After 96 h lethal concentration (LC50) for rui, 0.35 ppm; catla, 0.30 ppm; and mrigal fingerlings 0.3625 ppm, were calculated through probit analysis. Maximum mortality occurred at the highest concentration of diesel oil, and treated fingerlings showed behavioural and external morphologic alterations. Dissolved oxygen decreased with the increasing of oil concentrations, and water quality was poor among all the treatments. This study demonstrated that commercial diesel oil directly affects the survivability, behaviour, and external morphology of rui, catla, and mrigal fingerlings. It is expected that the present results will be beneficial to make awareness of the fretful effects of commercial diesel oil and other oils uses in the environment.

Assessment of the impact of fish seed stocking on fish yield in small reservoirs of Central India: towards sustainable management.

The present study assessed the impact of fingerling stocking of Indian major carps (Gibelion catla, Labeo rohita, and Cirrhinus mrigala) on fish yield in 24 small reservoirs of Central India. The time series data on fish stocking and yield were collected from the State Fisheries Department, Govt. of Chhattisgarh, for the year 2008 to 2016. The fish yield increased significantly (p < 0.05) from 87.11 to 379.13 kg/ha/year due to stocking indicating significant impact on fish production. The relationships between area, stocking density, and fish yield of reservoirs were also assessed. Stocking had a significant positive impact on fish yield (t test, p < 0.05). The important water quality parameters were also studied to have a conspicuous picture of eco-hydrological characteristics of these selected small reservoirs. The study forms a baseline for the small tropical reservoir fisheries of Central India (Chhattisgarh state) and suggests regional strategies for sustainable fisheries enhancement and management, employment generation, and nutritional security of a large number of fish-eating population.

Growth performance of Jayanti rohu with three species combination viz., Catla catla, Labeo rohita and Cirrhinus mrigala at different stocking densities

The present study was conducted to compare the growth performance of 9th generation Jayanti rohu with non-Jayanti rohu cultured together with Catla catla and Cirrhinus mrigala at different stocking densities for 90 days The experiment was carried out in homogenous rectangular cement cisterns in the wet laboratory of College of Fisheries, Assam Agricultural University, Raha. Four treatments with three replicates viz. Treatment-I, Treatment-II, Treatment-III and Treatment Control (reference treatment) were taken. Ten numbers of fishes were stocked in each cistern. Jayanti rohu was stocked at the rate of 35%, 40%, 45% and 0% in the treatments respectively. Non-Jayanti rohu was stocked at the rate of 40% in Control treatment The study revealed the effect of different stocking densities with better growth of Jayanti rohu in Treatment-I (35% stocking density) where stocking density of catla and mrigal was 55% and 10% respectively. The percentage weight gain of 9th generation Jayanti rohu over non-Jayanti rohu showed 31.60% in Treatment-I followed by 17.13% in Treatment-II and lowest was recorded at 6.65% in Treatment-III treatment. The result indicates better performance of Jayanti rohu in terms of net weight gain, average daily growth rate, Food Conversion Ratio (FCR), Specific Growth Rate (SGR), survivability and production compared to non-Jayanti rohu.