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The pattern of spatial fish assemblage, diversity, habitat, and potential impact of Nile tilapia (Oreochromis niloticus) was studied in a tropical reservoir of central India during June 2018–July 2019. A total of 21 species under six orders nine families and 18 genera were recorded which is comparatively low than previous records. The fish abundance similarity showed a maximum similarity of 78% between site 1 and site 3 clusters. The results of species composition showed increased abundance of O. niloticus species (> 80%) in the fishery and have now established feral population in the reservoir. The mean Simpson dominance index (1 − λ), the Shannon diversity index (H′), Pielou's evenness index (J′) and Margalef's richness index (d) were determined for three different sites followed by Mann–Whitney U test which showed a significant difference at spatial scale. Bray–Curtis cluster analysis of physicochemical parameters showed a similarity of 96% between site 1 and site 2. Comparison with the previous study three physicochemical parameters (total alkalinity, total hardness and chloride) showed the considerable changes. Relationships between fish assemblages and environmental parameters were examined by canonical correspondence analysis (CCA). Six physicochemical parameters (i.e., DO, pH, Nitrate, Mg, Phosphate and Silicate) showed statistically significant to shaping fish diversity (p

Floodplain wetlands are among the most threatened ecosystems. It is highly vulnerable to climate change, affecting the wetland ecosystem and its associated fisheries. In the face of data deficiency...

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.

The climate of Brahmaputra valley (located in the North-eastern Indian state of Assam) witnesses considerable changes with sub-tropical rain-storm atmosphere and has four well-defined seasons (monsoon, post-monsoon, winter and pre-monsoon) in a year. The state is experiencing extreme climatic events like erratic rainfall patterns (causing abnormally high floods) and drought-like situations in recent years, which adversely affects fish seed production thereby affecting pond aquaculture and fisheries enhancements in open-waters of the region. The present paper describes the major constraints faced by fish seed producers of the region because of extreme climatic events (abnormally high floods and prolonged dry spells) based on field studies in 27 fish seed production farms (randomly selected) located in three districts of Lower Brahmaputra Valley Zone of Assam, India. Primary data on different aspects of constraints faced by the fish seed producers because of extreme climatic events were collected and analysed. Rank Based Quotient values were calculated, based on ranks given by the fish seed producers for each constraint to prioritize them. Dominant constraint related to abnormally high floods faced by the fish seed producers was ‘loss of brood stock’ (Rank based quotient = 99.1) whereas the least important constraint was ‘entry of weeds/macrophytes’ during floods (Rank Based Quotient = 25.5). Constraints related to drought-like situations ranged from the least important ones like ‘low milt production of male brood fishes’ that had the lowest value (12.5) to the over-arching constraint of ‘inadequate water depth in fish ponds’ during pre-monsoon and prolonged dry spells (Rank Based Quotient = 100.0). Adaptive strategies developed by fish seed producers of the study region to overcome the major constraints have been outlined in the paper. The need for developing improved risk management at macro-level through appropriate policy support to fish seed producers in the fish-deficit region and suggested policy support measures for ensuring sustainability are discussed.

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.

An experiment was conducted to study the influence of environmental parameters and stocking density on growth, survival, feed utilization, and economic feasibility of a high value butter catfish, Ompok bimaculatus in floating cages in a large tropical reservoir of India for 180 days. The fingerlings (11.44 ± 1.33 cm; 8.05 ± 3.27 g) were stocked at three stocking densities, viz., 15, 25 and 35 fingerlings m-3 in GI cages (32m3) in triplicates. Commercial floating pellets were fed to fish at 5–3% of fish biomass. The results indicated that the fishes at the lowest stocking density of 15 fingerlings m-3 had significantly higher (p 0.05) between stocking densities of 15 fingerlings m-3 and 25 fingerlings m-3. The condition factor was insignificantly higher at lower densities and its values close to 1 indicated congeniality of reservoir ecosystem for cage culture of the species. The coefficient of variation of weight was significantly higher (24.19 ± 1.20) at 35 fingerlings m-3. The highest economic gains in terms of benefit cost ratio (1.77) were achieved at the lowest stocking density. The present study indicated better growth and economic returns at lower stocking densities of 15–25 fingerlings m-3. The nutrient load and plankton abundance were higher at culture site, however, did not vary significantly from reference sites throughout the culture period. Although most of the environmental parameters showed significant seasonal variations, dissolved oxygen showed significant positive relation (r = 0.86) with the growth of the fish. This is the first study reporting feasibility of cage culture of this highly renumerative species in open waters. The cage culture of this species will not only ensure better economic returns to the marginal cage farmers but will aid in the conservation of this species in natural ecosystem. Being a low volume high value species, the impact on environment will be less compared with high volume low value species. This study will serve as baseline for standardization of its grow-out protocol in cages and will be a step towards much needed species diversification for sustainable small scale cage farming in tropical reservoirs of Asia.

Eutrophication level in lakes and reservoirs depends on both internal and external phosphorus (P) load. Characterization of sediment P fractionation and identifying the P pollution sources are important for assessing the bio-availability of P and the dominant P source, for effectively controlling the water pollution. For determining the availability and sources of sediment P and eutrophication status, spatio-temporal variation in different P fractionation of sediment of hyper-eutrophic Krishnagiri reservoir, Tamil Nadu, India, was investigated. Sediment average total P (TP) content ranged from 4.62 to 5.64 g/kg. Main phosphorus form was the inorganic P (IP), and it makes up to 73.4–87.7% of TP. Among the different P fraction, viz. calcium bound (Ca-P), iron bound (Fe–P), aluminium bound (Al-P), exchangeable (Ex-P) and Organic-P (Org-P), Ca-P was the dominating fraction in both IP and TP. Trend of IP fraction was as follows: Ca-P > Fe–P > Al-P > Ex-P in pre-monsoon season, Fe–P > Ca-P > Al-P > Ex-P in monsoon and Ca-P > Al-P > Fe–P > Ex-P in post-monsoon. Overall the trend was as follows Ca-P > Fe–P > Al-P > Org-P > Ex-P. Bio-available-P (BAP) fractions ranged from 35.2 to 64.0% of TP, indicating its comparative higher value. Pearson’s correlation matrix revealed that there was strong correlation among the different P fractions. Factor analysis indicates that different fractions of P were the dominating factor than the other sediment parameters. The observed variation in sediment P fractionation indicate the differences in source and characterization of P which is very helpful for implementation of effective management practices in controlling pollution that arises due to phosphorus in this hyper-eutrophic reservoir.

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 changing foodweb scenario due to exotic fish species invasions. The information generated here could be applied for future research on similar ecosystems for deducing management actions.

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.

Freshwater has a significant role in determining the ecological environment, public health and socio-economic development. This study analyzed the spatio-temporal variation in surface water quality of the tropical reservoir Mettur, India, to determine whether its water is suitable for human consumption and aquatic ecosystem. Thus, 21 water quality parameters were monitored seasonally (pre-monsoon, monsoon and post-monsoon) at nine sampling sites covering riverine, transitional and lacustrine zones of the reservoir during 2018. The study revealed spatial variation, which was due to input from industrial and domestic wastewater in the lacustrine zone of the reservoir. However, temporal variability often exceeded spatial variability. The factor analysis indicates that basin geology, anthropogenic stress and agricultural applications simultaneously act vital roles in deciding the reservoir water quality. Based on similarity of water quality parameters, cluster analysis grouped all the nine sampling sites into three clusters of high, moderate and less polluted sites. Correlation analysis also indicated that multiple sources influence the reservoir water quality during all the seasons. Based on BIS and WHO values, the calculated water quality index (134–158) indicates that water of the reservoir is not fit for human consumption, while the trophic state of this reservoir is moderately-eutrophic to eutrophic. However, with precaution, this aquatic body seems to be suitable for aquatic life and fish growth. The overall water quality deterioration of this reservoir indicates a strong need for development of a regular monitoring system for implementation of an effective management system to safeguard human and environmental health.

The present study evaluated the effectiveness of stocking the Gangetic carps, viz. Labeo catla, Labeo rohita, and Cirrhinus mrigala, in a large tropical reservoir, Uttar Pradesh, India. Time series data of 22 years (1998 to 2019) on fingerling stocking and fish harvest were collected from the State Department of Fisheries, Govt of Uttar Pradesh. The average annual stocking was 36 nos.ha−1 yr−1, and the fingerling stocking size was ranged between 10 and 90 mm total length (TL) with a mean of 30 mm TL. The average fish production potential of the reservoir was estimated at 77.15 kg ha−1 yr−1. The analysis revealed that fish yield from the reservoir progressively increased from 75.02 t to 297.39 t with a mean of 148.82 ± 69.45 t. The regression analysis between the stocking density and yield of stocked species showed an insignificant relation in the reservoir (R2 = 0.0873, p = 0.2495). The percentage change in the production of stocked species in comparison with the previous year was found to be negative for 12 years between 1998 and 2019 indicated an unstable trend. The finding indicated that low stocking density, very small size at stocking, the low conversion efficiency of the photosynthetic energy to fish (0.016%), and the dominance of catfishes were the major causes for the low fish productivity. We suggest greater stocking density of 500 fingerlings ha−1 yr−1, stocking of fingerlings (> 100 mm TL), in situ breeding and rearing in cages and pens, adoption of cage culture technology, and identification and conservation of the breeding ground of the Gangetic carps to optimize the management regime in utilizing the production potential of reservoirs vis-a-vis ensuring livelihood security and sustainability of the fishers.

The present study aims to understand the spatio-temporal dynamics in habitat ecology and fish assemblage and determine the relationship of habitat transition and fish distribution in a large riverine- reservoir cascade system (Sardar Sarovar Reservoir part in Madhya Pradesh). This study was carried out along a 125 km riverine- reservoir interface during 2018-2020. The study showed presence of a total of 110 fish species (104 spp. in upstream main Narmada River stretch excluding reservoirs, 56 in RRI and 39 in Sardar Sarovar reservoir). We recorded 50 species common in upstream riverine stretch of Narmada and the RRI while RRI uniquely harboured 3 native species (Chitala chitala, Labeo boga, Salmostoma phulo) not previously reported from Narmada River stretch upstream. The SIMPER analysis showed presence of S. phulo causing 27.91%, Schistura dayi (3.71%), Rita pavimentata (3.41%) of dissimilarity among S1, S2 and S3(non-confluence zone) and S4 (confluence zone). The analysis of data indicated disappearance of some species like deccan peninsular carp Labeo fimbriatus, Mahseer Tor khudree which was earlier reported but was absent in recent years. The statistical correlation of environmental variables with observed abundances fish feeding guilds showed significant positive correlation with specific conductivity and total dissolved solids content of the water. The CCA indicated association among omnivorous fishes of the reservoir with water temperature; total dissolved solids; specific conductivity; total alkalinity; chlorophyll and NO3-N. The herbivore fishes were found to be more associated with Magnesium, Dissolved Oxygen and phosphorus content of the water while insectivorous fishes were more associated with the silicate and transparency of the water. The abundance of omnivores species indicated dominance of generalist fish species rather than specialists in the interface region of reservoir showing conservation and ecological importance of the ecosystem. The baseline information generated on fish assemblage and ecological perspectives of the river reservoir interface and science based management measures recommendations formulated in the study are critical for the sustaining fish diversity, promoting fisheries enhancement, and management planning of tropical reservoirs.

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. gariepinus since this fish was caught by gillnets. Such results suggest more work to determine if gillnet fishing in this reservoir will help mitigate the negative effects of invasive fish. Snakeheads, however, which have high market demand, appear not to be investigating the ability of gillnet fishing in this reservoir to contribute to mitigating the negative effects of invasive species. The modelling of Karapuzha reservoir showed a decline in the predicted biomass of some groups (Eels, Snakeheads, Minor Carps and Barbs) because of trophic response and relationships, and failed to give maximum sustainable yield .The new tools are designed to support policy decisions and incorporated into frameworks to integrate the effects of the stressors mentioned above to promote policy decision-making, particularly for ecosystem-based management (EBM), which tests the environment. The Ecosim routine shows that the presence of major carps does not affect other functional environmental organisations in this state and has predicted those groups and are not detrimental. This study will assist Indian Major Carp Stock Managers in enhancing fish productivity. New tools like this support policy-making integration with the impact of aforementioned stressors in reservoirs. This is the first time the Ecopath with Ecosim reservoir system has been predicted to temporarily shift due to fishing effects. This is the first time. This study helps manage resource conservation and management of informed and ecosystem-based fisheries choices. Our study analysed the social and economic elements of Karapuzha Fisheries which might link all these subsystems within a socio-ecological scenario. The modelling of the Karapuzha Reservoir provided an overall understanding of eco-dynamics and the role of interactions among the fish groups particularly since it eliminates the detrimental effects, in particular it eliminates the detrimental effects imposed by the invasive fish (C. gariepinus O.mossambicus). Gillnet fishing has a positive impact on several indigenous fish.

Wetlands provide a great ecological service by accumulating and sequestering carbon in their soils and thus help in mitigating climate change caused due to global warming. However, the capacity and efficiency of different types of wetlands vary considerably depending upon the nature of the wetland, hydrology, biogeochemistry, climatic condition, and many other factors. In the present paper, we have studied the carbon accumulation and sequestration in three different wetlands, one sewage fed, and two floodplain oxbow lakes in the West Bengal state of India. The selected wetlands vary in terms of ecological regimes such as water volume, depth, link channel, agricultural runoffs, primary productivity, macrophyte coverage, and fishery. The carbon accumulation in the wetlands, which varied from 48.53 to 143.17 Mg/ha up to 30-cm depth of soil, was much higher than that in the corresponding upland sites. The difference was much higher in the floodplain wetlands. So the study revealed that wetlands are better carbon sinks than the corresponding reference sites and the carbon sequestration potential varies according to the type of wetlands. A positive correlation was also observed between macrophyte coverage and the amount of C stored in the wetlands.

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 (3.5±0.08g) were stocked in the ratio 4:3:3 at the rate of 20 no./m2 in pens (0.1ha each) in triplicate. Grass carp (7.1±0.42g) was stocked in pen at the rate of 20 no./m2. The fishes were fed with pelleted feed twice a day at the rate of 2-3% of body weight per day. The seed was overwintered in pens for a period of 90 days from November 2019-January 2020. Average weight recorded at the end of culture period was 25.13±1.70g, 18.11±0.63g, 14.53±0.87g and 39.20±1.90g in L. catla, L. rohita, C. mrigala and C. idella respectively. The survival of fish ranged from 70 to 81%. Growth performance and feed utilization efficiency of grass carp was significantly higher (p

Assessment of life history strategies of economically important small indigenous fishes (SIF) which are rich in nutritive values is essential and imperative to artisanal and subsistence small-scale inland fisheries of Indian tropical reservoirs. The present investigation aims to estimate the food selectivity in juveniles and adults, reproductive traits such as sexual maturity, gonadosomatic index, ova diameter, and fecundity of Gudusia chapra from a large impounded ecosystem of India. A total of 668 (Juvenile 129, adult 539) specimens, 37 to 142 mm standard length and 0.89–25.68 g body weight were collected during October 2014–September 2015. The qualitative estimation of the stomach contents revealed herbi-omnivorous feeding behavior of fish. The mean relative gut length (mRGL) of the species was 1.557 ± 0.024 in juveniles and 1.154 ± 0.012 in adults. The sex ratio was 1:1.30 with dominance of females in the population though insignificant. The total length at which 50% individual attain maturity (TL50) was estimated as 80.50 mm based on the logistic curve. The absolute fecundity of the individuals ranged from 749 to15044, and ova diameter ranged from 0.10–2.00 mm. The gonadal indices (GSI, MGSI, and DI) indicated that spawning extended throughout the year with peak reproductive activity in October, March–April, and July (mean absolute fecundity ranged from 4000 to 6000). The present study characterized biological and reproductive traits of G. chapra from a large reservoir ecosystem and demonstrated a new trend of reproductive pattern which will serve as benchmark data for future assessment and management planning of this species in impounded waters. The study also suggested some specific management measures for sustainable exploitation and conservation of small indigenous species.

The spawning and well-being of fish in an ecosystem are closely linked to climatic cues, viz., temperature and rainfall. Reduced fitness can affect the reproductive performance and lead to skipped spawning. Benchmarking the threshold fitness required for a fish population to achieve readiness for spawning, and understanding how climatic parameters influence the fitness will aid in predicting the fate of its reproductive success in future climatic conditions. This study determined the threshold condition factor pre-spawning fitness (Kspawn50) at which 50% of the female Channa punctata population can be deemed fit for spawning. The optimal climate within which pre-spawning fitness is attained by this species under Indian climatic conditions was also identified. The study was conducted from June 2015 to September 2016, covering two spawning seasons (June–August) in a Gangetic floodplain wetland of West Bengal, India. The non-parametric Kaplan–Meier method (survival fit) was used for estimation of pre-spawning fitness. “Ready to spawn” females were classified based on binary coding of the gonadal maturity stages. The thermal and precipitation range within which spawning fitness is achieved was identified by using the locally weighted smoothing technique. Female C. punctata pre-spawning fitness (Kspawn50) ranged from 1.26 to 1.39 with an estimated median of 1.29 units. Temperatures between 29 and 32 °C and rainfall above 100 mm were conducive to attaining the requisite pre-spawning fitness in C. punctata. This is the first study benchmarking the pre-spawning fitness and optimal climate for C. punctata. Understanding spawning requirements can inform the climate change–induced impacts on reproductive plasticity and evolutionary adaptations of snakeheads in the Ganga river basin.

India is blessed with vast floodplain wetland resources of 0.5 million ha that are distributed in the Eastern and North Eastern States. They possess varying morphometry, ecological profile, trophic...

Objectives We aimed to evaluate blood pressure (BP) in Indian children who had similar demographic characteristics but hailed from different altitudes. Methods BP of school going children, aged 5 to 12 years, at five different locations varying in altitude (near sea level: n = 425; 2000 feet: n = 244; 4000 feet: n = 248; 6000 feet: n = 242 and 8000 feet: n = 250) was measured in a mountainous district in Himalaya. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded by aneroid sphygmomanometer in the sitting posture using a calibrated instrument and four trained resident doctors. The average of three readings was taken. Results Of the 1229 children whose data were analyzed, 50.4% were boys. SBP showed a progressive rise from 99.5 (4.00) mmHg [mean (standard deviation)] at near sea level to 106.7 (4.17) mmHg at 8000 feet. Similarly, DBP showed a rise from 60.1 (3.67) mmHg to 66.8 (4.58) mmHg over the same altitude range. Analysis of covariance for BP variation with altitude, with age as covariate, indicated a modest but statistically significant rise in both SBP and DBP with altitude. Higher BP values was noted among children residing at higher than at lower altitude (0.8% at sea level to 18.8% at 8000 feet). Correlations between SBP and DBP values and height and weight, though positive and significant at p Conclusions These data will help in correct interpretation of BP readings in children residing at high altitude.

The present investigation attempted environmental characterization of two ecologically distinct oxbow lakes through zooplankton taxonomic indices using a comparative approach. These closed and seasonally open oxbow lakes are subjected to eutrophication due to different nutrient concentration and eco-hydrological characteristics. The zooplanktons are closely link with surrounding environment throughout their life cycles and change rapidly, hence act as potential indicator of eutrophication. The study examined the assemblage pattern of zooplankton community and trophic state of two ecologically distinct oxbow lakes based on eco-hydrological factors 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 to assess the degree of eutrophication. The Kruskal-Wallis test confirmed the heterogeneity of the eco-hydrological factors between the oxbow lakes. Both lakes showed transition from high meso-eutrophic to moderately eutrophic state with mTSI, mTSIrot and mTSIcr values of 54.90±11.71 and 56.95±15.64, 59.55±4.54 and 60.26±4.48, 55.79±4.76 and 60.00±4.03 in Khalsi (seasonally open) and Akaipur (closed) respectively. The Canonical Correspondence analysis (CCA) revealed water quality parameters comparison NO3−N, water temperature and pH have contributed more in enhancement of abundance of eutrophication indicator species Brachionus and Keratella. An overview of worldwide use of rotifer and crustacean based indices in assessment of TSI has also been synthesized. The use of these zooplankton indices to evaluate the trophic status of the ecologically distinct lakes is highly recommended for water quality assessment and management.

The present study aims to understand the spatio-temporal dynamics in habitat ecology and fish assemblage and determine the relationship of habitat transition and fish distribution in a large riverine-reservoir cascade system (Sardar Sarovar Reservoir part in Madhya Pradesh). This study was carried out along a 125-km riverine-reservoir interface (RRI) during 2018-2020. The study showed presence of a total of 110 fish species (104 spp. in upstream main Narmada River stretch excluding reservoirs, 56 in RRI, and 39 in Sardar Sarovar reservoir). We recorded 50 species common in upstream riverine stretch of Narmada and the RRI while RRI uniquely harbored 3 native species (Chitala chitala, Labeo boga, Salmostoma phulo) not previously reported from Narmada River stretch upstream. The similarity percentage (SIMPER) analysis showed presence of S. phulo causing 27.91%, Schistura dayi (3.71%), and Rita pavimentata (3.41%) of dissimilarity among Maheshwar (S1), Rajghat (S2), Koteshwar (S3) non-confluence zone, and Kakrana (S4)-confluence zone. The analysis of data indicated disappearance of some species like deccan peninsular carp Labeo fimbriatus, Mahseer Tor khudree which was earlier reported but was absent in recent years. The statistical correlation of environmental variables with observed abundances of fish feeding guilds showed significant positive correlation with specific conductivity and total dissolved solid content of the water. The canonical correspondence analysis (CCA) indicated association among omnivorous fishes of the reservoir with water temperature; total dissolved solids; specific conductivity; total alkalinity; chlorophyll; and NO

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 to assess the degree of eutrophication. The Kruskal-Wallis test confirmed the heterogeneity of the eco-hydrological factors between the oxbow lakes. A total of 68 zooplankton species were identified of which rotifers (69%), cladocerans (18%), copepods (3%), ostacods (3%) and protozoans (7%). Seasonal fluctuation of relative abundance and frequency of species in both lakes have been well presented. Both lakes showed transition from high meso-eutrophic to moderately eutrophic state with mTSI, mTSIrot and mTSIcr values of 54.90±11.71 and 56.95±15.64, 59.55±4.54 and 60.26±4.48, 55.79±4.76 and 60.00±4.03 in Khalsi (seasonally open) and Akaipur (closed) respectively. The Canonical Correspondence analysis (CCA) revealed water quality parameters comparison NO3-N, water temperature and pH have contributed more in enhancement of abundance of eutrophication indicator species Brachionus and Keratella. The TSIs values indicated a prompt aquaculture fisheries management measures like stocking of planktivorous fish (Labeo catla and Puntius sp.) for both the lakes before they reach in plunged state at which their restoration might become a challenge. An overview of worldwide use of rotifer and crustacean based indices in assessment of TSI has also been synthesized. The use of these zooplankton indices to evaluate the trophic status of the ecologically distinct lakes is highly recommended for water quality assessment and management. Based on this study strategies could be developed to plan and manage floodplain oxbow lakes for fisheries enhancement programme as well as as conservation of biodiversity.

Tropical inland capture fisheries are susceptible to a series of vulnerabilities such as habitat destruction, biodiversity loss, pollution, overfishing, invasive species and anthropogenic climate change. A comprehensive review of the impact of climatic uncertainties on Indian inland fisheries has not been adequately attempted yet. Recent approaches emphasizing ecosystem-based management in a regional context, specific to inland fisheries for combating climatic changes, have not been reported to date. The paper presents a critical bibliometric review of the climatic vulnerabilities faced by Indian inland fishery resources and various adaptive and mitigation strategies put forward by the country for the sustainability of the resources. In this communication, a systematic review of the impact of climate change and other stressors on various inland ecosystems of the subcontinent and the ecosystem-based management strategies adopted in India is presented and discussed.

The present study was conducted for 240 days to evaluate the effects of stocking density based on growth attributes, digestive enzymes, muscular composition, biochemical and physiological responses of Labeo rohita fingerlings in tropical inland open water cages. L. rohita (30.35±1.08 g) were randomly distributed into three treatments, namely low stocking density, LSD (10 m− 3), medium stocking density, MSD (20 m− 3) and high stocking density, HSD (30 m− 3) in triplicates. Fish were fed twice daily with CIFRI CAGEGROW® floating feed (crude protein-28%, crude fat-4%). Fish growth and feed efficiency was higher (P+, Cl− and K+) observed under crowding stress. Based on growth attributes and multiple biomarker responses, L. rohita @ 10 m− 3 found to be optimum density for inland open water cage culture.

The present study was conducted for 240 days to evaluate the effects of stocking density based on growth attributes, digestive enzymes, muscular composition, biochemical and physiological responses of Labeo rohita fingerlings in tropical inland open water cages. L. rohita (30.35 ± 1.08 g) were randomly distributed into three treatments, namely low stocking density, LSD (10 m−3), medium stocking density, MSD (20 m−3) and high stocking density, HSD (30 m−3) in triplicates. Fish were fed twice daily with CIFRI CAGEGROW® floating feed (crude protein-28%, crude fat-4%). Fish growth and feed efficiency were higher (p +, Cl− and K+) was observed under crowding stress. Based on growth attributes and multiple biomarker responses, L. rohita @ 10 m−3 was found to be the optimum density for inland open water cage culture.

Documenting and updating life history traits of wild fish are prerequisite for undertaking any conservation and enhancement programme from inland waters. The spotted snakehead Channa punctata (Bloch, 1793) is an important small indigenous food fish in Asian countries which has high nutritional and commercial value. This is the first work on describing life-history traits including growth pattern, condition factors (Fulton’s, KF; Allometric, KA; Relative condition, KR; Relative weight, WR), form factor (a3.0), size at first sexual maturity (Lm) and natural mortality (Mw) in the Gajner Beel, northwestern Bangladesh during July 2018 to December 2019. Traditional fishing gears were used for sampling. Different lengths (i.e., total length, TL; standard length, SL) and body weight (BW) of each individual were taken using digital slide calipers and an electronic balance to the nearest 0.01 cm and 0.01 g, respectively. In total, 583 individuals ranging from 5.8-22.8 cm TL and 1.96-115.08 g BW were collected in this study. On the basis of b value, the growth pattern of C. punctata was isometric (b=3.0) in all the LWRs. Also, all LWRs were highly significant with r2 values ≥0.979. The LLR was highly significant (p

The geographic information systems (GIS) play an important role in all geospatial aspects of assessment, monitoring and management of inland open water resources for strategic development in fisheries sector. In India, reservoir fisheries development is one of the flagship programme and several initiatives have been taken up towards enhancement and sustainable development. The present study investigates spatio-temporal changes in ecology and fisheries in Hirakud reservoir, Odisha build across river Mahanadi which features one of the largest dam in South Asia. The reservoir is mainly utilized for electricity generation, irrigation and offers tremendous scope to support fisheries and livelihood. As per the seasonal variation analysis, water spread area was at the minimum during premonsoon period. Most of the water quality parameters including nitrate, phosphate, BOD and alkalinity were higher in the premonsoon period and overall the parameters were under favourable range for fisheries. The present investigation from the fish landing sites of the reservoir, recorded merely 40 fish species, indicating loss of fish diversity as compared to the historical reports. The IUCN conservation status showed that among the 40 species only one species, Wallago attu is under VU category and 4 species Chitala chitala, Ompok bimaculatus, Ailia colia and Bagarius bagarius are under NT category. The analysis of time series annual fish catch data using ARIMA model forecasted the increasing trend of fish production. The water quality parameters were presented in GIS platform for better understanding of the spatial variations over time. Habitat protection of fish breeding grounds, closed seasons, mesh size regulations, scientific management and community participation are recommended as the measures for conservation of fish diversity and sustainable enhancement of fish production in the reservoir.

The present study investigates the impact of climatic variability and fisher’s adaptation to climate-induced threats in a seasonally open floodplain wetland in West Bengal, India. The analysis of climatological trend indicated an increase in the air temperature over the last 2 decades and a gradual fall in the amount of rainfall to the tune of 36.9% from 2000 to 2019. In recent years, this wetland has witnessed notable changes in various aspects viz. reduction in average water depth (74.3%), increase in nitrate concentration (44.4%), area shrinkage (77.7%), macrophyte infestation (80%), decline in plankton diversity (54%), macro-zoo-benthos diversity (31%), fish diversity (22.8%), and fish production making the wetland fisheries more vulnerable. In view of the above, climate-resilient fisheries practice at local level is needed. In this study, the climbing perch, Anabas testudineus emerged as a significant fishery and provided a significant contribution to the tune of 34.5% supporting the livelihood of the fisher-folks. The propagation of A. testudineus, a tolerant high-value indigenous species, is proposed as an effective tool to combat the consequences of climatic variability especially the low water area and depth prevailing in the wetland. The study emphasized on the need for concerted research programs on various emerging issues in floodplain wetland fisheries, climate-resilient/tolerant fish species and documentation of adaptation strategies for sustainable floodplain wetland fisheries and livelihood security.

The present study assessed the occurrence and impact of heat waves on the ecology of two ecosystems namely Bhomra wetland and Ganga River stretch, India. The water samples collected from these ecosystems were analyzed for estimating the hydrological and biological variables during heat wave. The inland heat index (IHI) was derived from the climatic variables, relative humidity and temperature. The study indicated the predominant and periodic occurrence of inland heat waves (IHW) with indices ranging from 34.8 to 42.8 °C and 35.9 to 43.5 °C at the Bhomra and Ganga River stretch respectively during the summer months (March-June). The first two components of the principal component analysis of physico-chemical parameters and heat index explained 45.6% and 59% of the variation in the Bhomra and Ganga River stretch respectively. PCA showed a similar pattern in variation of IHWs and dissolved oxygen, nutrients, hardness and alkalinity, but a distinct pattern with conductivity and TDS in the wetland. IHW exhibited a similar pattern of variation with TDS, conductivity, dissolved oxygen, pH and hardness and distinct pattern with alkalinity, phosphate and nitrate in the river stretch. The first two components of PCA of IHI and plankton abundance explained 89% of the variation and IHI had a similar pattern of variation with the abundance of diatoms and a diverse pattern of variation with blue-green and green algae in the studied ecosystems which might affect the food availability of the associated fishes. The study suggests that IHW influences the water quality and primary producers and also summarizes the impact of IHW on ecosystem services and necessitates mitigation measures.

The COVID-19 pandemic has created unprecedented human health crisis in recent global history with rippling social and economic effects. The outbreak in India has resulted in emergency lockdown in the country for more than two months and that caused decline in the fish catch has severely affected the life and livelihoods of the fishers. The wetlands offers tremendous scope for expanding both culture and capture based fisheries for livelihood security of fishers. They also play a key role in socio-economic development by generating employment and livelihood in the studied regions. In the present study a systematic rapid assessment was conducted to find the impact of COVID-19 lockdown on floodplain wetland fisheries in India to evaluate the impact of lockdown on wetland fisheries production, income and food access. We undertook a rapid telephone survey with 176 wetland fishers in 3 states. Fishers of three Indian States Bihar, West Bengal, and Assam lost 20, 25, and 9 fishing days respectively. Fish harvest during March to May was 32, 44 and 20 percentage lower respectively than the previous year in Bihar, West Bengal and Assam. Fishers of Bihar, West Bengal and Assam lost income of INR 10000/-, 12500/- and 4500/-due to lockdown. Demand supply gap during the lockdown led to the in 20–40 percent increase in farm gate price of fishes at the wetland level. The wetland fisheries potential to contribute to the Sustainable Development Goals (SDGs) ‘eradication of poverty’; ‘zero hunger’ and ‘good health and well being’ have also been considerably impacted due to this pandemic. The paper discusses several magnitudes of immediate impacts of lockdown on floodplain wetland fishers livelihood, income and food access, highlights issues and suggests strategies, advisories and decisions support to mitigate the impact.

India has different bio-climatic zones that support diverse aquatic habitats rich in biodiversity. For effective conservation of endangered species in its habitat, it is essential to know the distribution of the fish species in the environmental range and for this species distribution models are the efficient and innovative tools. The present study used MaxEnt model to develop the probability distribution model highlighting the distribution of the fish species by analyzing the known occurrence records of Denison barb under genus Sahyadria (Sahyadria denisonii Day 1865 and Sahyadria chalakkudiensis (Menon, Rema Devi & Thobias 1999)) in relation to environmental variables typically incorporating seasonal and temporal variability. AUC of the models for Sahyadria species depicted good fitness. Both the species were found sensitive to 'Solar radiation', 'Temperature seasonality' and 'Temperature annual range' and these variables were assessed as the significant predictors. The sensitivity of distribution of both species to these environmental variables was found correlated with their breading and spawning seasons. 'Precipitation' was determined as a significant climatic envelop influencing distribution of the species associated with the river flow. The models showed that distribution of S. denisonii in the higher precipitation areas compared to S. chalakkudiensi. The probability distribution model with respect to distribution of both the species indicates a lineage barrier at Palghat Gap supporting the studies of earlier workers. At the latitudinal scale, prediction of the suitable ecological habitat provides the detailed insight into the distribution of all the genetic lineages of the genus Sahyadria. Evidently, the findings of this study can assist in determining ecological niches for other threatened and endangered species of other areas and may aid in field surveys as well as developing conservation plans.

Information on various aspects of reproductive traits of female pool barbs from various stretches of Ganga River basin, India was generated in relation to climatic variability. The presumptions surrounding – minnows being the first and easily hit by climatic variability, was validated. GAM models revealed low threshold rainfall requirement (>50 mm) within a wide temperature range (20–30 °C) necessary for attainment of breeding GSI (>10.5 units). Pre-spawning fitness (Kspawn50) and size at 50% maturity (LM50) benchmarked through Kaplan-Meier survival estimates were in the range 1.61–1.67 units (Fulton condition factor) and 8.6–9.0 cm respectively. Mapping of climate preferendum through LOESS smoothing hinted both low-mild rainfall (50–150 mm) and high rainfall conditions (400–700 mm) conducive for attaining pre-spawning fitness while no dependence on temperature was observed. First maturity of females was encountered at 4.7 cm within the size range 4.4–12.6 cm. The present study hinted a probable reduction (1.4–1.8 cm) in size at maturity of female pool barbs. We observed pool barbs can breed within a wide thermal regime following slightest of rainfall events. Collating this with the present rates of climatic variability, we infer negligible threat of changing climate on reproduction of Puntius sophore in near future – contrary to the existing presumptions. Owing to the easiness in attainment of pre-spawning fitness under an apparently flexible climate preferendum, ‘skipped spawning’ decisions while facing climatic variability also seem minimum. The recorded breeding thresholds may serve as future references while assessing climate driven changes on reproduction and evolutionary adaptations in Gangetic minnows.

The main objectives of the present study were to quantify the environmental, especially temperature and rainfall, effects on breeding phenology of selected catfish species and to predict changes in breeding phenology of the selected species in relation to climatic variability for the Ganga River Basin. The study showed that changes in rainfall pattern may have the most profound effect on gonad maturation and breeding of Mystus tengara and Mystus cavasius followed by the effect of increased water temperature due to rising air temperature. Indication of region-specific adaptation was noticed in reproductive phenology of Eutropiichthys vacha based on local trends of warming climate. The other habitat parameters, such as dissolved oxygen, alkalinity, nitrate, and phosphate, were correlated with gonad maturity and spawning. Climatic variability may bring region-specific changes in breeding phenology of fish species in the Ganga River. Under a warming climate, changes in precipitation pattern manifested into riverine flow pulse may be the key driver in dictating breeding phenology. Our study indicates E. vacha as a climate sensitive species that may be selected as a target species for climate change impact studies.

Raman and SER spectra of 1-H-2 (tolylazo) imidazole (Tai H) are reported for the first time. Monomolecular layer of TaiH is formed on silver nano particles (SNPs) at a concentration of 4.93×10−6 M in Ag-sol. TaiH molecules are adsorbed on to SNPs the through the imidazole N atom and undergo trans-to-cis dark isomerization as evidenced by the appearance of signature cis-peaks and the UV-Vis absorption spectra. Stable non-aggregated SNPs are resulted by the interaction of TaiH and the particle size is significantly reduced. DFT calculations based on single Ag-atom model are in excellent agreement with experimental observations.

Fish assemblage structure in Panchet, a large tropical reservoir along river Damodar, major tributary of river Ganga in India, was studied along the spatial gradient of the impoundment. Fish samples were collected bimonthly from October 2014 to September 2016. Fish community structure in terms of species composition, relative abundance, and trophic and conservation status was recorded. Spatial fish diversity was analyzed from riverine, transitional, and lacustrine zones. Sixty-two fish species were recorded wherein the family Cyprinidae dominated in number of species (26) followed by Bagridae (5). Shannon diversity index, evenness index, and species richness did not reveal significant variation (p > 0.05) across different zones. Relative abundance of individuals and species richness were maximum in the transitional zone and minimum in the lacustrine zone. Multi-dimensional scaling of fish assemblage revealed similar pattern in the riverine and transitional zones. Trophic guild of fishes indicated dominance of carnivorous species followed by planktivores. Conservation status (IUCN 2017.3) showed 4 fish species in Near Threatened category. The study suggests conservation of fish habitats to maintain diversity and sustained production. The baseline information generated in the study will be beneficial for monitoring the alteration in fish assemblage, conservation of fish diversity, and management planning.

Wetlands are rich biological resources and support livelihood and nutritional security to a huge populace globally. In the present study, two ecologically distinct floodplain wetlands viz., Khalsi and Akaipur located in the sub-basin of Jamuna river in lower Gangetic basin, were studied for abundance, species richness and diversity indices of macro-zoobenthic communities across four seasons. The selected wetlands vary in terms of ecological regimes such as, water volume, depth, link channel, agricultural runoffs, macrophyte coverage etc. Khalsi, a seasonally open beel (wetland) that occasionally exchange water with river Jamuna during high flood, while Akaipur is a closed beel with no exchange of water. The studies indicated higher community richness in macrophyte dominated seasonally open Khalsi wetland (22species) as compared to closed Akaipur wetlands (20 species). The community abundance was higher in Khalsi (8496 nos/m2) as compared to Akaipur. Average Dominance, Simpson and Shannon diversity indices for Khalsi and Akaipur were calculated as 0.3, 0.7 & 1.5 and 0.2, 0.8 & 1.7, respectively. The community structure of wetlands revealed dominance of a single group, gastropoda (99%), followed by bivalvia (0.64%), diptera (0.27%) and oligochaeta (0.09%) in Khalsi, whereas, Akaipur depicted community structure with dominance of gastropoda (46.18%) followed by oligochaeta (41.36%), diptera (11.22%) and bivalvia (1.24%). The trophic state index (TSI) based on chlorophyll a (Chla), Secchi disc transparency and total phosphorus showed significant (p

Wetlands are considered as one of the most effective carbon (C) sink among various ecosystems. To substantiate this view, the present investigation was conducted in one of the units of sewage fed East Kolkata wetlands (EKW), a Ramsar site, over a period of 3 years. The result revealed that because of high primary productivity due to abundance of primary producers and other sources of C input primarily through sewage influx, there is net positive balance of C in the system. The rate of C accumulation estimated through C budget was 1245.27–2490.55 kg C ha−1 year−1 while the rate estimated through sediment core analysis came out to be 1584 kg C ha−1 year−1. The amount of total C deposited up to 15 cm depth in sediment was 29.37 Mg ha−1, quite higher than the C deposited up to 15 cm depth of reference upland soil which was measured at 23.79 Mg ha−1. If C burial from this experiment in 55 ha is up-scaled for entire EKW of 12,500 ha area, then it empirically corresponds to 56.97–113.94 Gg CO2 captured from atmosphere per annum. EKW is not only used for aquaculture production thereby harvesting blue carbon but also has great potential to accumulate C in its sediments and thus helping mitigate climate change.

A fully developed laminar flow through semi-elliptic annulus formed between two confocal elliptical ducts, driven by a constant pressure-gradient, has been analyzed. The elliptic cylindrical coordinate system has been used to determine the exact solutions for “wide” and “narrow” semi-elliptic annuli with cross sections being symmetric about the minor and major axes of the confocal elliptic boundaries, respectively. For both configurations, exact analytical expressions have been obtained for velocity distribution, volume flow rate, shear stress, and Poiseuille number. The results are expressed in terms of two non-dimensional physical parameters: the ratio of the length of the semi-minor axis to the semi-major axis of the outer boundary, [Formula: see text], [Formula: see text], and the ratio of the length of semi-major axes of inner and outer elliptic boundaries, [Formula: see text], [Formula: see text], with c being the non-dimensional focal distance of the elliptic boundaries. Based on the analytical expressions, the graphical and tabulated results of the flow fields are presented for representative values of [Formula: see text] and [Formula: see text] to illustrate the characteristic features of the flow. Numerical evaluation of the analytical expressions shows that the flow field and the corresponding distributions of velocity and shear stresses are characteristically different for wide and narrow semi-elliptic annuli. In addition to the analytical results, a bivariate Chebyshev pseudospectral method is formulated in the elliptic-cylindrical coordinate system for obtaining the numerical solution of the problem. The numerical results show that the proposed method yields “exponential convergence” or “infinite order of accuracy,” as expected from a spectral method; exact agreement has been observed between the analytical and numerical results.