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Not AvailableTropical reservoir ecosystems cover more than 3.51 million ha in India which are the major sources of fish production from inland open waters and supports rich diversity of fish. The present study quantifies fisheries enhancement and evaluates the impact of stocking of Indian major carp fingerlings in six large reservoir ecosystems of India. Analysis of time series data revealed a significant increase (p<0.05) in fish yield from 12.3kgha-1yr-1 in 2004-05 to 52.4kgha-1yr-1 in 2016-17 due to stocking. The average fish yield of these six reservoirs was estimated to be higher than the national average of 33kgha-1yr-1 recorded for large Indian reservoirs. Fingerling stocking had a significant positive impact on fish yield (r=0.238, p=0.035). The reservoir water storage level was positively correlated (r=0.621, p<0.05) to fish production. The study also shows that the reservoir habitat support 99 finfish species in the studied central Indian reservoirs of which two species belong to endangered category warranting conservation efforts. This study is the first of its kind on assessing the impact of stocking in large number of tropical reservoirs including the largest reservoir in the country revealing positive effect on fish yield. The fish yield of 85.8kgha-1yr-1 obtained in Gandhisagar reservoir (72300ha), India revealed that fisheries enhancement is effective and remunerative. The study also highlights the global status of stocking impact in large reservoirs and deliberates issues and suggests management strategies for sustainable fisheries enhancement in large tropical reservoirs.Not Availabl

Occurrence, Morpho-Histopathological Characterization, and Infection Dynamics of Posthodiplostomum sp. (Strigeidida: Diplostomidae) in Cyprinid Fish of the Ganga River

A metacercarial infection of Posthodiplostomum sp. (Strigeidida: Diplostomidae) was reported in the cyprinid fish, Labeo catla and Pethia conchonius and was identified based on clinical signs, cyst morphometry and characteristic histopathological lesions. The parasite was oval-round in shape, encysted in musculocutaneous tissues, and well encapsulated. The cyst was 1.02±0.02 by 0.79±0.02 mm and 1.02±0.02 by 0.75±0.02 mm in L. catla and P. conchonius, respectively. Microscopically, the multifocal hyperpigmented areas in the musculocutaneous tissues showed pericystic melanization, focal necrosis, and an infiltration of mononuclear leukocytes. Out of the 5,820 freshwater fish examined, only 3 L. catla were found to be infected in October at the Balagarh and in August, 13 P. conchonius were found to be infected at the Farakka stretch of the Ganga River. The spatio-temporal prevalence of Posthodiplostomum sp. in L. catla and P. conchonius was <1%, indicating a lower infection rate. This is the first report of Posthodiplostomum sp. infection in P. conchonius and from the Ganga River. It is also the first report of Posthodiplostomum sp. infection in L. catla in the Ganga River

Co-Prevalence of Virulence and Pathogenic Potential in Multiple Antibiotic Resistant Aeromonas spp. from Diseased Fishes with In Silico Insight on the Virulent Protein Network

Aeromonas species exhibit widespread presence in food, poultry, and aquaculture. They are major multi-drug-resistant fish pathogens. This study aims to identify Aeromonas species harbouring virulence genes aerolysin, flagellin, and lipase from diseased fishes of Assam wetlands with association with antibiotic resistance and in vivo pathogenicity. One hundred and thirty-four Aeromonas strains were isolated and thirty representative species identified using genus-specific 16S rRNA gene amplification. A. veronii was most prevalent (53.7%) followed by A. hydrophila (40.2%), A. caviae (4.47%), and A. dhakensis (1.49%). Ninety percent (90%) of strains harboured at least one of the studied virulence genes: aerA (73.3%), lip (46.6%), and flaA (26.6%). The highest multiple antibiotic resistance (MAR) index 0.8 corresponded to A. hydrophila DBTNE1 (MZ723069), containing all the studied genes. The lowest LD50 values (1.6 &times; 106 CFU/fish) corresponded to isolates having both aerA and lip. &beta;-lactams showed utmost resistance and lowest for aminoglycosides. There was a significant (p &lt; 0.05) Pearson chi-square test of association between the occurrence of virulence and antibiotic resistance. The in silico protein&ndash;protein interaction revealed important drug targets, such as &sigma;28 transcription factor, aminoacyl-tRNA synthetase, and diacylglycerol kinase, with significant (p &lt; 0.05) enrichment. This study suggests that fish-isolate Aeromonas strains represent potential threat to aquaculture with subsequent risk of transferring antibiotic resistance to human pathogens

Genetic differentiation and phylogenetic relationship of 11 Asian Sisorinae genera (Siluriformes: Sisoridae) with new record of Pseudolaguvia foveolata

Studies on Sisorinae systematics have been largely restricted to morphological data with few studies on examination of phylogenetic relations. However, no study has been done to evaluate genetic distance of the genera under Sisorinae sub-family and detailed phylogenetic relations within it. We used nuclear recombination activating 2 (rag2) gene and mitochondrial cytochrome c oxidase I (COI) gene from 64 species to examine genetic differentiation and phylogenetic relationships within 11 Asian Sisorinae genera. The range of interspecies K2P distance for rag2 was 0–0.061 and COI was 0–0.204. Phylogenetic analysis based on maximum likelihood (ML) and Bayesian (BI) approaches for each locus individually and for the concatenated rag2 and COI sequences revealed three major subclades viz. Bagariini, Sisorini and Erethistini under subfamily Sisorinae. The analysis based on COI gene showed ((Sisorini, Bagariini), Erethistini) relationship. Rag2 and combined rag2 and COI showed ((Sisorini, Erethistini), Bagariini) relationship. Combined rag2 and COI analyses resulted into better resolved trees with a good bootstrap support. In this study, new record of Pseudolaguvia foveolata (Erethistini) has been documented based on 13 specimens collected from Torsa River, Jaldapara, Alipurduar district, West Bengal, India (26°43′44.66″ N and 89°19′32.34″ E), extending its distribution range in Brahmaputra drainage, India. The genetic distance between the P. foveolata new record and the reported P. foveolata (holotype: UMMZ 244867) was 0.00 at both rag2 and COI locus and it was further grouped with P. foveolata Type specimen (holotype: UMMZ 244867) with 100% bootstrap support. This report gives additional information on occurrence of the species P. foveolata, along with discussion on morphometric, meristic and molecular (COI and rag2 gene) data

Length-Weight relationships of six indigenous fish species from the river Cauvery and its estuary, India

The present study estimated length–weight relationships (LWRs) for six indigenous fish species (Barilius gatensis, Salmostoma acinaces, S. boopis, Puntius amphibius, Hemibagrus punctatus and Ambassis miops) based on specimens collected from River Cauvery (including estuary) during July 2017–January 2020. The sampling surveys were carried out in three distinct sampling seasons, viz., the pre‐monsoon (March–May), the monsoon (July–October) and the post‐monsoon (November–February). Majority of the fish specimens dealt in the study were collected from multi‐meshed monofilament gill nets (mesh sizes 18, 30, 45, 60, 90, 110, 120 and 150 mm) operated by local fishers. For those sites situated in the protected areas, sampling was carried out by cast nets with prior permission from the local administration and the collected fishes were released back into river after length–weight measurements. The length measurements were noted as total length (TL) measured to the nearest 0.1 cm by using a digital Vernier caliper. A digital balance was used for weight measurements with an accuracy of 0.01 g. The study recorded a new maximum length of 48 cm for H. punctatus. The LWR data generated from the present study are significant for proper assessment of the stock status and their management, if collected together with other essential biological and physical parameters