Length–weight relationships of seven small indigenous fish species from the Tapti River in peninsular India

Length–weight relationships of seven small indigenous fishes collected from the middle and lower stretch of the Tapti River in India were determined. The specimens were caught with drag nets (0 mm mesh size), gill nets (10–20 mm knot-to-knot mesh length) and scoop nets (0 mm) from the Maharashtra, and Gujarat state stretches of the Tapti River from November 2018 to December 2019. Digital calliper and digital balances were used to measure the total length (TL) and body weight (BW) of all fish specimens respectively. The growth coefficient b varied from 2.758 (Parambassis ranga) to 3.298 (Osteobrama cotio), and the LWRs were highly significant (p < .005). The present study established LWRs for the first time for seven fish species in the respective riverine habitat, including providing a new maximum length record for Corica soborna. The results of the present study will be useful for sustainable management and conservation of respective species in the river and its associated waterbodies

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