Dr Uttam Kumar Sarkar - Academia.edu (original) (raw)

Papers by Dr Uttam Kumar Sarkar

Journal of Water and Climate Change

Climate change associated with anthropogenic stressors are considered the main threat to the trop... more Climate change associated with anthropogenic stressors are considered the main threat to the tropical wetlands, resulting in reduced water connection followed by a decline in ecological functions. This article presents a systemic approach to assess the present ecological status of a tropical floodplain wetland concerning the fisheries and associated ecosystem services. The analysis of historic climatic data indicated significant change (increasing average annual air temperature, R2 = 0.098; decreasing total annual rainfall, R2 = 0.042). In addition, a significant reduction in the wetland area was also observed. Altogether, 45 fish species were reported in the studied wetland, of which 2 are listed as endangered and 7 are near threatened. The present study demonstrated the variation of the important fisheries-related environment and nutrient parameters of the wetland through the geographic information system (GIS)-based spatial distribution map for the reader's digest. It has bee...

Ecohydrology & Hydrobiology

Food Web Modelling is used as a method for an interpretation of ecological processes and for stud... more Food Web Modelling is used as a method for an interpretation of ecological processes and for studying the impact of fishing on biodiversity. An overview of ecological dynamics, as well as the significance of interactions between functional groups was obtained by modelling Ecopath with Ecosim in Karapuzha reservoir, in India. The modelling exercise revealed fishing and predator pre-interaction from the main drivers of this ecosystem. This is the first time in the Indian reservoir system, Ecopath with Ecosim was used to predict temporal shifts caused by fishing impacts. The mean trophic level of the catch was 2.53, not varying much throughout the entire time series and the Kempton Index (Biomass diversity) has declined slightly. The values of the L index were between the reference values of the L index 25% and L index 50%, implying overfishing, the favourable impact of gillnet fishing on some indegenous fish was likely due to the predation release of invasive species such as C. gariep...

Aquatic Ecosystem Health & Management

Reservoirs are aquatic resources with the potential to increase India's fish production throu... more 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) c...

The rapid degradation, overexploitation and encroachment of floodplain wetlands have led to consi... more The rapid degradation, overexploitation and encroachment of floodplain wetlands have led to considerable decline in fish diversity and production from these invaluable aquatic resources threatening livelihood of the dependent fishers. The climate change evident in the fast few decades have further aggravated the problem of eutrophication causing water stress, sedimentation leading to rampant macrophyte proliferation affecting ecological and economic functioning of these ecosystems. Macrophyte control and management needs serious attention for sustaining ecosystem services provided by these resources. In this direction pen culture of grass carp, Ctenopharyngodon idella as a biocontrol for macrophytes along with Indian major carps was implemented in a co-management mode in Beledanga, a typical floodplain wetland, a gradually shrinking, macrophyte dominated floodplain wetland in lower Ganga basin. Indian major carps Labeo catla (6.28±0.23g), Labeo rohita (5.1±0.12g), Cirrhinus mrigala ...

Environmental Science and Pollution Research, 2022

India has different bioclimatic zones and supports diverse aquatic habitats rich in biodiversity.... more India has different bioclimatic zones and supports diverse aquatic habitats rich in biodiversity. For effective conservation of the endangered species in its habitat, it is essential to know the distribution of fish species in the environmental range, and for this, species distribution models are the efficient and innovative tools. The present study used the MaxEnt modeling technique for developing probability distribution models highlighting the distribution of fish species by analyzing the known occurrence records of Denison barb under genus Sahyadria (Sahyadria denisonii Day 1865 and Sahyadria chalakkudiensis (Menon et al., Rec Zool Surv India 97:61–63, 1999)) in relation to environmental variables typically incorporating seasonal and temporal variability. AUC of the models for Sahyadria species depicted good fitness. Both species were found sensitive to “solar radiation,” “temperature seasonality,” and “temperature annual range” and assessed as significant predictors. The sensitivity and distribution of both species to these environmental variables were found correlated with their breading and spawning seasons. “Precipitation” was determined as one of the significant climatic envelopes influencing the distribution of the species associated with river flow. The models showed the distribution of S. denisonii in the higher precipitation areas compared to S. chalakkudiensis. The probability distribution model with respect to the distribution of both species indicates a lineage barrier at Palghat Gap supporting the earlier studies. At the latitudinal scale, prediction of the suitable ecological habitat provides a detailed insight into the distribution of all genetic lineages of the genus Sahyadria. Evidently, the findings of this study can assist in determining ecological niches for endangered species of other areas and may aid in field surveys as well as developing conservation plans.

Journal of Ecophysiology and Occupational Health, 2011

The present study was conducted to assess the current freshwater fish biodiversity status of an u... more The present study was conducted to assess the current freshwater fish biodiversity status of an unexplored river Ghaghara, a major tributary of river Ganga in Uttar Pradesh, India. Altogether, 62 species of fish representing 48 genera and 24 families were described. The various diversity index packages have been used to assess the fish diversity and diversity is also correlated with habitat variables. The Cypriniformes was recorded to be the most predominated order, contributing to 41.8% of fish species followed by Siluriformes (36.4%). The study shows that this river supports considerable percentage of food fish (79.0%), aquarium fish (48.4%), highly priced fishes (33.9%) and also sport fish (9.7%). The threat status as per current IUCN Red List criteria showed that most of the species are under lower risk least concern (LRlc) category, however, Indian assessment shows that about 23% fish species under threatened list (EN= 4, VU=10). Several anthropogenic activities like barrages, ...

In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eut... more In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eutrophication due to disconnection from river that compromises the hydro-ecological functions. This requires systematic studies to assess the ecological health of the water bodies using different indices and suggest appropriate strategies to manage the resources. The zooplanktons are closely link with surrounding environment throughout their life cycles and change rapidly in their growth and population when changes occurs in the surrounding, hence act as potential indicator of eutrophication. The present study examined the assemblage pattern of zooplankton community and trophic state of two ecologically distinct oxbow lakes based on eco-hydrological characteristics and community structure of rotifers and planktonic crustaceans seasonally over a period of 2 years. Comprehensive trophic state index (mTSI), rotifer trophic state index (mTSIROT) and Crustacean based indices (TSICR) were used t...

Journal of Ecophysiology and Occupational Health, 2015

The population of mahseers are declining very fast in different parts of India due to indiscrimin... more The population of mahseers are declining very fast in different parts of India due to indiscriminate fishing of brood stock and juveniles, fast degradation of aquatic ecosystems, construction of dams, barrages and weirs under river valley projects etc and therefore the species deserves high conservation values in India. To save this prized resource, effective conservation and rehabilitation strategies need to be planned and implemented in the country. This requires knowledge of current status of fish, declining trend, aquaculture potential and population structure in the wild habitats, which is yet not carryout comprehensively. In the present paper, an attempt has been made to review evolutionary history, present status and role of conservation biology for their conservation, sustainable utilization and enhancement. Based on the review, discussed potential promising plans, priorities and suggestions, which would help saving mighty mahseers across the country.

Aquaculture, 2021

A detailed investigation on mass mortality of fishes was conducted in a small tropical reservoir-... more A detailed investigation on mass mortality of fishes was conducted in a small tropical reservoir- Derjang (20o50'32.0"N, 85o01'14.8″E), Odisha, India. Mortality mostly occurred in Systomus sarana followed by Labeo rohita , Cirrhinus mrigala , Labeo catla , Ompok bimaculatus , Labeo calbasu and Mastacembelus armatus. During 20 days of disease occurrence in May–June 2019, a total of about 3000 kg of fish died. The clinical signs in Cyprinid group were haemorrhagic spots, ulcerative lesions, rotten and pale patches in gills due to septicemic disease whereas haemorrhagic spots were the only prominent symptoms observed in Silurid group. Bacteriological isolation and identification through conventional and molecular techniques revealed that Klebsiella pneumoniae was the most common pathogen recovered from S. sarana , C. mrigala and O. bimaculatus. Further Aeromonas hydrophila , Acinetobacter baumannii were isolated from L. rohita and L. catla respectively. The role of these pathogens for this disease outbreak in multiple fish species is discussed in perspective of environmental factors. Sudden environmental alternation by the supercyclone Fani (3rd May 2019) on the coastal part of Odisha might have played a key role to translate the aquatic bacteria into the virulent infective pathogens. In the experimental challenge study, isolated bacteria showed pathogenicity in respective hosts as that in the reservoir. Thus this further revealed both bacteria and fish specific virulency with a variation in LD 50 values. All the gram negative bacterial isolates were found to resist ampicillin and amoxicillin-clavulanic acid and most of them were TEM gene positive. However, the bacteria were found to be susceptible to the rest of the nineteen antibiotics. These findings suggested that the sudden cyclone is an enormous threat to reservoir aquaculture, and should be taken into consideration before breeding, stocking and harvesting of fishes. • Disease outbreak in reservoir during Summer, 2019 caused mass mortality of many freshwater fishes with septicemic symptoms • Klebsiella pnumoniae was the most dominating pathogen recovered, besides Aeromonas hydrophila and Acinetobacter baumannii • Sudden environmental alternation by the cyclone Fani might have played a key role to flare up the virulent pathogens. • Specificity and virulence of bacteria were found host-dependent with variable LD 50 as revealed by challenge experiments [ FROM AUTHOR] Copyright of Aquaculture is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Aquatic Ecosystem Health & Management, 2021

Biological invasions are a worldwide threat to the aquatic systems and have the potential to homo... more Biological invasions are a worldwide threat to the aquatic systems and have the potential to homogenize entire foodwebs and shift species abundance distributions to more skewed ones. Invasion impacts include effects on the foodweb structure and ecosystem functioning leading to a loss in native fish biodiversity and commercially important fisheries in many open water systems. The impacts of invasives are generally devastating as they spread in the foodweb with each species potentially interacting with multiple species. The foodweb modeling studies conducted in different inland aquatic ecosystems show that not all exotics cause a detrimental effect on the resilience of an ecosystem. Information on the foodweb structure and ecosystem properties is a prerequisite for formulating management protocols for conserving biodiversity, enhancement programmes and sustaining fisheries. The present paper reviews the impacts of invasive fishes in Indian aquatic ecosystems in the context of a changi...

Indian Journal of Fisheries, Sep 28, 2017

Fishermen communities, in general and inland fishermen in particular are one of the most marginal... more Fishermen communities, in general and inland fishermen in particular are one of the most marginalised and vulnerable group in India with extreme poverty and very low economic base. The present study was conducted to investigate the economic vulnerability of the fishermen households of two beels (floodplain wetlands) in West Bengal (Kholshi and Akaipur) and one beel in Assam (Deepor) based on a sample of 185 fishermen households. By employing the methodology developed by Bene (2009) it was found that the average vulnerability scores were 0.21, 0.14 and 0.33 for Kholsi, Akaipur and Deepor beels, respectively on a scale of 0 to 1. The study showed that in flood plain wetlands with well managed cooperative society, optimum and scientific stocking, income diversification and participatory management, agricultural land holdings can significantly lower economic vulnerability of the fishermen households. The study suggests the Government to facilitate creation of supplementary income generating opportunities and integrated agricultural activities in the vicinity of the wetlands. There is potential for developing eco-tourism with suitable infrastructure in beels like Deepor, which may help to provide supplementary employment to fishermen.

International Journal of Current Microbiology and Applied Sciences, 2019

Journal of Aquaculture Research & Development, 2017

Reservoirs nicknamed as sleeping giants have been identified as the nearest possible alternative ... more Reservoirs nicknamed as sleeping giants have been identified as the nearest possible alternative source of fish production only recently. But the average fish productivity of reservoirs in India is nearly 30 Kg/ha and this is not sufficient enough to match the ever-doubling rate of population demands. The paper thus discusses the various enhancement strategies adopted for Indian reservoirs. The paper emphasizes enhancing fish production by manipulating biological and physical basis of production along with other strategies for maximizing fishing in the reservoirs. The challenges involved in fish production using various strategies have also been discussed.

Biodiversitas Journal of Biological Diversity, 2014

Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance a... more Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India. Biodiversitas 15: 186-194.The present study describes the analysis and mapping of the differentmeasurements of freshwater fish biodiversity of the Upper Ganges basin in the Himalayan region using spatial interpolation methods ofGeographical Information System. The diversity, richness and abundance of fishes for each sampling location were determined andKriging interpolation was applied on each fisheries measurement to predict and produce semivariogram. The semivariogarms producedwere cross validated and reclassified. The reclassified maps for richness, abundance and diversity of fishes, occurrence of cold waterthreatened fish and abundance of important genera like Tor, Schizothorax and species were produced. The result of the Krigingproduced good results and overall error in the estimation process was found signific...

Journal of Aquaculture Research & Development, 2014

The reservoirs play an important role in the developmental process of a Nation and also have an i... more The reservoirs play an important role in the developmental process of a Nation and also have an integral role in fisheries and livelihood security of the local community. With the increase in population growth reservoirs are becoming important provider of animal protein and for generation of employment in particular to poorer sectors of the people. Reservoirs have many uses from generation of electricity to irrigation purpose and also providing habitat to fishes and other aquatic life and in turn also help to provide feed and create revenue for fish communities. In India, reservoirs are playing a crucial role in the fisheries. Fish communities are often used as indicators of environmental quality. In terms of fish diversity altogether 117 fish species were recorded from Indian reservoirs exhibiting rich fish diversity. These reservoirs have both positive and negative impacts on fishes and other aquatic environment. Therefore, present study is emphasized on synthesizing the available information on fish diversity and community structure of the potential Indian reservoirs and its effects on fisheries and other aquatic environment in reservoirs in India. Some strategies have been suggested for sustaining river and reservoir fish biodiversity.

Journal of Water and Climate Change

Riverine fisheries will have a knock-on effect due to the changes in water flow and increased irr... more Riverine fisheries will have a knock-on effect due to the changes in water flow and increased irrigation in the agriculture sector to cope with the climate change impact. The present study showed a very high perception existing in the fishing community about climate change observed in the last 10 years. About 95% of fishermen understand temperature and sea levels are changing, whereas 91% responded that rainfall is changing and salinity also is increasing and 86% think extreme rainfall is affecting productivity. Moreover, though the monsoon period is shorter than the non-monsoon period, about 62.3% of the total fish catch in River Cauvery takes place during the monsoon. The variations in climate can enormously impact the inland fisheries, especially the riverine resources, their productivity and sustainability. With this view, it was attempted to: (i) investigate the changing climate trends in the major river basins of the Peninsular region of India over the decades, (ii) key driver...

Arabian Journal of Geosciences

Journal of environmental biology, 2013

This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 fami... more This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at p< 0.001. The condition factor (K) varied considerably from 0.76 and 2.95, with a mean K = 1.43 which may be attributed to different environmental conditions of the river basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.

Indian Journal of Fisheries, 2020

The study presents the status of fish diversity, abundance and habitat structure of Surha Lake, w... more The study presents the status of fish diversity, abundance and habitat structure of Surha Lake, which is a perennial and natural lake fed by the river Ganga. The study was conducted between 2011 to 2013 covering pre and post-monsoon seasons. In total, 4,852 individual fish specimens were collected representing 66 fish species belonging to 23 families. The species diversity comprised 65 species in pre-monsoon and 60 species in post-monsoon season (p<0.05). The highest species diversity was recorded for the family Cyprinidae (22), followed by Bagridae (7). An assessment of conservation status of 66 fish species as per IUCN Red List 2019 criteria listed 6 species under near threatened (NT), 54 under least concern (LC) and two species under vulnerable (VU) category. The study reports several commercially important species under near threatened (Chitala chitala, Labeo pangusia, Ompok bimaculatus, Ompok pabda, , Ailia coila and Bagarius bagarius), which makes Surha Taal an important na...

Journal of Water and Climate Change

Climate change associated with anthropogenic stressors are considered the main threat to the trop... more Climate change associated with anthropogenic stressors are considered the main threat to the tropical wetlands, resulting in reduced water connection followed by a decline in ecological functions. This article presents a systemic approach to assess the present ecological status of a tropical floodplain wetland concerning the fisheries and associated ecosystem services. The analysis of historic climatic data indicated significant change (increasing average annual air temperature, R2 = 0.098; decreasing total annual rainfall, R2 = 0.042). In addition, a significant reduction in the wetland area was also observed. Altogether, 45 fish species were reported in the studied wetland, of which 2 are listed as endangered and 7 are near threatened. The present study demonstrated the variation of the important fisheries-related environment and nutrient parameters of the wetland through the geographic information system (GIS)-based spatial distribution map for the reader's digest. It has bee...

Ecohydrology & Hydrobiology

Food Web Modelling is used as a method for an interpretation of ecological processes and for stud... more Food Web Modelling is used as a method for an interpretation of ecological processes and for studying the impact of fishing on biodiversity. An overview of ecological dynamics, as well as the significance of interactions between functional groups was obtained by modelling Ecopath with Ecosim in Karapuzha reservoir, in India. The modelling exercise revealed fishing and predator pre-interaction from the main drivers of this ecosystem. This is the first time in the Indian reservoir system, Ecopath with Ecosim was used to predict temporal shifts caused by fishing impacts. The mean trophic level of the catch was 2.53, not varying much throughout the entire time series and the Kempton Index (Biomass diversity) has declined slightly. The values of the L index were between the reference values of the L index 25% and L index 50%, implying overfishing, the favourable impact of gillnet fishing on some indegenous fish was likely due to the predation release of invasive species such as C. gariep...

Aquatic Ecosystem Health & Management

Reservoirs are aquatic resources with the potential to increase India's fish production throu... more 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) c...

The rapid degradation, overexploitation and encroachment of floodplain wetlands have led to consi... more The rapid degradation, overexploitation and encroachment of floodplain wetlands have led to considerable decline in fish diversity and production from these invaluable aquatic resources threatening livelihood of the dependent fishers. The climate change evident in the fast few decades have further aggravated the problem of eutrophication causing water stress, sedimentation leading to rampant macrophyte proliferation affecting ecological and economic functioning of these ecosystems. Macrophyte control and management needs serious attention for sustaining ecosystem services provided by these resources. In this direction pen culture of grass carp, Ctenopharyngodon idella as a biocontrol for macrophytes along with Indian major carps was implemented in a co-management mode in Beledanga, a typical floodplain wetland, a gradually shrinking, macrophyte dominated floodplain wetland in lower Ganga basin. Indian major carps Labeo catla (6.28±0.23g), Labeo rohita (5.1±0.12g), Cirrhinus mrigala ...

Environmental Science and Pollution Research, 2022

India has different bioclimatic zones and supports diverse aquatic habitats rich in biodiversity.... more India has different bioclimatic zones and supports diverse aquatic habitats rich in biodiversity. For effective conservation of the endangered species in its habitat, it is essential to know the distribution of fish species in the environmental range, and for this, species distribution models are the efficient and innovative tools. The present study used the MaxEnt modeling technique for developing probability distribution models highlighting the distribution of fish species by analyzing the known occurrence records of Denison barb under genus Sahyadria (Sahyadria denisonii Day 1865 and Sahyadria chalakkudiensis (Menon et al., Rec Zool Surv India 97:61–63, 1999)) in relation to environmental variables typically incorporating seasonal and temporal variability. AUC of the models for Sahyadria species depicted good fitness. Both species were found sensitive to “solar radiation,” “temperature seasonality,” and “temperature annual range” and assessed as significant predictors. The sensitivity and distribution of both species to these environmental variables were found correlated with their breading and spawning seasons. “Precipitation” was determined as one of the significant climatic envelopes influencing the distribution of the species associated with river flow. The models showed the distribution of S. denisonii in the higher precipitation areas compared to S. chalakkudiensis. The probability distribution model with respect to the distribution of both species indicates a lineage barrier at Palghat Gap supporting the earlier studies. At the latitudinal scale, prediction of the suitable ecological habitat provides a detailed insight into the distribution of all genetic lineages of the genus Sahyadria. Evidently, the findings of this study can assist in determining ecological niches for endangered species of other areas and may aid in field surveys as well as developing conservation plans.

Journal of Ecophysiology and Occupational Health, 2011

The present study was conducted to assess the current freshwater fish biodiversity status of an u... more The present study was conducted to assess the current freshwater fish biodiversity status of an unexplored river Ghaghara, a major tributary of river Ganga in Uttar Pradesh, India. Altogether, 62 species of fish representing 48 genera and 24 families were described. The various diversity index packages have been used to assess the fish diversity and diversity is also correlated with habitat variables. The Cypriniformes was recorded to be the most predominated order, contributing to 41.8% of fish species followed by Siluriformes (36.4%). The study shows that this river supports considerable percentage of food fish (79.0%), aquarium fish (48.4%), highly priced fishes (33.9%) and also sport fish (9.7%). The threat status as per current IUCN Red List criteria showed that most of the species are under lower risk least concern (LRlc) category, however, Indian assessment shows that about 23% fish species under threatened list (EN= 4, VU=10). Several anthropogenic activities like barrages, ...

In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eut... more In recent years closed and seasonally open oxbow lakes and river floodplains are subjected to eutrophication due to disconnection from river that compromises the hydro-ecological functions. This requires systematic studies to assess the ecological health of the water bodies using different indices and suggest appropriate strategies to manage the resources. The zooplanktons are closely link with surrounding environment throughout their life cycles and change rapidly in their growth and population when changes occurs in the surrounding, hence act as potential indicator of eutrophication. The present study examined the assemblage pattern of zooplankton community and trophic state of two ecologically distinct oxbow lakes based on eco-hydrological characteristics and community structure of rotifers and planktonic crustaceans seasonally over a period of 2 years. Comprehensive trophic state index (mTSI), rotifer trophic state index (mTSIROT) and Crustacean based indices (TSICR) were used t...

Journal of Ecophysiology and Occupational Health, 2015

The population of mahseers are declining very fast in different parts of India due to indiscrimin... more The population of mahseers are declining very fast in different parts of India due to indiscriminate fishing of brood stock and juveniles, fast degradation of aquatic ecosystems, construction of dams, barrages and weirs under river valley projects etc and therefore the species deserves high conservation values in India. To save this prized resource, effective conservation and rehabilitation strategies need to be planned and implemented in the country. This requires knowledge of current status of fish, declining trend, aquaculture potential and population structure in the wild habitats, which is yet not carryout comprehensively. In the present paper, an attempt has been made to review evolutionary history, present status and role of conservation biology for their conservation, sustainable utilization and enhancement. Based on the review, discussed potential promising plans, priorities and suggestions, which would help saving mighty mahseers across the country.

Aquaculture, 2021

A detailed investigation on mass mortality of fishes was conducted in a small tropical reservoir-... more A detailed investigation on mass mortality of fishes was conducted in a small tropical reservoir- Derjang (20o50'32.0"N, 85o01'14.8″E), Odisha, India. Mortality mostly occurred in Systomus sarana followed by Labeo rohita , Cirrhinus mrigala , Labeo catla , Ompok bimaculatus , Labeo calbasu and Mastacembelus armatus. During 20 days of disease occurrence in May–June 2019, a total of about 3000 kg of fish died. The clinical signs in Cyprinid group were haemorrhagic spots, ulcerative lesions, rotten and pale patches in gills due to septicemic disease whereas haemorrhagic spots were the only prominent symptoms observed in Silurid group. Bacteriological isolation and identification through conventional and molecular techniques revealed that Klebsiella pneumoniae was the most common pathogen recovered from S. sarana , C. mrigala and O. bimaculatus. Further Aeromonas hydrophila , Acinetobacter baumannii were isolated from L. rohita and L. catla respectively. The role of these pathogens for this disease outbreak in multiple fish species is discussed in perspective of environmental factors. Sudden environmental alternation by the supercyclone Fani (3rd May 2019) on the coastal part of Odisha might have played a key role to translate the aquatic bacteria into the virulent infective pathogens. In the experimental challenge study, isolated bacteria showed pathogenicity in respective hosts as that in the reservoir. Thus this further revealed both bacteria and fish specific virulency with a variation in LD 50 values. All the gram negative bacterial isolates were found to resist ampicillin and amoxicillin-clavulanic acid and most of them were TEM gene positive. However, the bacteria were found to be susceptible to the rest of the nineteen antibiotics. These findings suggested that the sudden cyclone is an enormous threat to reservoir aquaculture, and should be taken into consideration before breeding, stocking and harvesting of fishes. • Disease outbreak in reservoir during Summer, 2019 caused mass mortality of many freshwater fishes with septicemic symptoms • Klebsiella pnumoniae was the most dominating pathogen recovered, besides Aeromonas hydrophila and Acinetobacter baumannii • Sudden environmental alternation by the cyclone Fani might have played a key role to flare up the virulent pathogens. • Specificity and virulence of bacteria were found host-dependent with variable LD 50 as revealed by challenge experiments [ FROM AUTHOR] Copyright of Aquaculture is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Aquatic Ecosystem Health & Management, 2021

Biological invasions are a worldwide threat to the aquatic systems and have the potential to homo... more Biological invasions are a worldwide threat to the aquatic systems and have the potential to homogenize entire foodwebs and shift species abundance distributions to more skewed ones. Invasion impacts include effects on the foodweb structure and ecosystem functioning leading to a loss in native fish biodiversity and commercially important fisheries in many open water systems. The impacts of invasives are generally devastating as they spread in the foodweb with each species potentially interacting with multiple species. The foodweb modeling studies conducted in different inland aquatic ecosystems show that not all exotics cause a detrimental effect on the resilience of an ecosystem. Information on the foodweb structure and ecosystem properties is a prerequisite for formulating management protocols for conserving biodiversity, enhancement programmes and sustaining fisheries. The present paper reviews the impacts of invasive fishes in Indian aquatic ecosystems in the context of a changi...

Indian Journal of Fisheries, Sep 28, 2017

Fishermen communities, in general and inland fishermen in particular are one of the most marginal... more Fishermen communities, in general and inland fishermen in particular are one of the most marginalised and vulnerable group in India with extreme poverty and very low economic base. The present study was conducted to investigate the economic vulnerability of the fishermen households of two beels (floodplain wetlands) in West Bengal (Kholshi and Akaipur) and one beel in Assam (Deepor) based on a sample of 185 fishermen households. By employing the methodology developed by Bene (2009) it was found that the average vulnerability scores were 0.21, 0.14 and 0.33 for Kholsi, Akaipur and Deepor beels, respectively on a scale of 0 to 1. The study showed that in flood plain wetlands with well managed cooperative society, optimum and scientific stocking, income diversification and participatory management, agricultural land holdings can significantly lower economic vulnerability of the fishermen households. The study suggests the Government to facilitate creation of supplementary income generating opportunities and integrated agricultural activities in the vicinity of the wetlands. There is potential for developing eco-tourism with suitable infrastructure in beels like Deepor, which may help to provide supplementary employment to fishermen.

International Journal of Current Microbiology and Applied Sciences, 2019

Journal of Aquaculture Research & Development, 2017

Reservoirs nicknamed as sleeping giants have been identified as the nearest possible alternative ... more Reservoirs nicknamed as sleeping giants have been identified as the nearest possible alternative source of fish production only recently. But the average fish productivity of reservoirs in India is nearly 30 Kg/ha and this is not sufficient enough to match the ever-doubling rate of population demands. The paper thus discusses the various enhancement strategies adopted for Indian reservoirs. The paper emphasizes enhancing fish production by manipulating biological and physical basis of production along with other strategies for maximizing fishing in the reservoirs. The challenges involved in fish production using various strategies have also been discussed.

Biodiversitas Journal of Biological Diversity, 2014

Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance a... more Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India. Biodiversitas 15: 186-194.The present study describes the analysis and mapping of the differentmeasurements of freshwater fish biodiversity of the Upper Ganges basin in the Himalayan region using spatial interpolation methods ofGeographical Information System. The diversity, richness and abundance of fishes for each sampling location were determined andKriging interpolation was applied on each fisheries measurement to predict and produce semivariogram. The semivariogarms producedwere cross validated and reclassified. The reclassified maps for richness, abundance and diversity of fishes, occurrence of cold waterthreatened fish and abundance of important genera like Tor, Schizothorax and species were produced. The result of the Krigingproduced good results and overall error in the estimation process was found signific...

Journal of Aquaculture Research & Development, 2014

The reservoirs play an important role in the developmental process of a Nation and also have an i... more The reservoirs play an important role in the developmental process of a Nation and also have an integral role in fisheries and livelihood security of the local community. With the increase in population growth reservoirs are becoming important provider of animal protein and for generation of employment in particular to poorer sectors of the people. Reservoirs have many uses from generation of electricity to irrigation purpose and also providing habitat to fishes and other aquatic life and in turn also help to provide feed and create revenue for fish communities. In India, reservoirs are playing a crucial role in the fisheries. Fish communities are often used as indicators of environmental quality. In terms of fish diversity altogether 117 fish species were recorded from Indian reservoirs exhibiting rich fish diversity. These reservoirs have both positive and negative impacts on fishes and other aquatic environment. Therefore, present study is emphasized on synthesizing the available information on fish diversity and community structure of the potential Indian reservoirs and its effects on fisheries and other aquatic environment in reservoirs in India. Some strategies have been suggested for sustaining river and reservoir fish biodiversity.

Journal of Water and Climate Change

Riverine fisheries will have a knock-on effect due to the changes in water flow and increased irr... more Riverine fisheries will have a knock-on effect due to the changes in water flow and increased irrigation in the agriculture sector to cope with the climate change impact. The present study showed a very high perception existing in the fishing community about climate change observed in the last 10 years. About 95% of fishermen understand temperature and sea levels are changing, whereas 91% responded that rainfall is changing and salinity also is increasing and 86% think extreme rainfall is affecting productivity. Moreover, though the monsoon period is shorter than the non-monsoon period, about 62.3% of the total fish catch in River Cauvery takes place during the monsoon. The variations in climate can enormously impact the inland fisheries, especially the riverine resources, their productivity and sustainability. With this view, it was attempted to: (i) investigate the changing climate trends in the major river basins of the Peninsular region of India over the decades, (ii) key driver...

Arabian Journal of Geosciences

Journal of environmental biology, 2013

This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 fami... more This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at p< 0.001. The condition factor (K) varied considerably from 0.76 and 2.95, with a mean K = 1.43 which may be attributed to different environmental conditions of the river basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.

Indian Journal of Fisheries, 2020

The study presents the status of fish diversity, abundance and habitat structure of Surha Lake, w... more The study presents the status of fish diversity, abundance and habitat structure of Surha Lake, which is a perennial and natural lake fed by the river Ganga. The study was conducted between 2011 to 2013 covering pre and post-monsoon seasons. In total, 4,852 individual fish specimens were collected representing 66 fish species belonging to 23 families. The species diversity comprised 65 species in pre-monsoon and 60 species in post-monsoon season (p<0.05). The highest species diversity was recorded for the family Cyprinidae (22), followed by Bagridae (7). An assessment of conservation status of 66 fish species as per IUCN Red List 2019 criteria listed 6 species under near threatened (NT), 54 under least concern (LC) and two species under vulnerable (VU) category. The study reports several commercially important species under near threatened (Chitala chitala, Labeo pangusia, Ompok bimaculatus, Ompok pabda, , Ailia coila and Bagarius bagarius), which makes Surha Taal an important na...