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Aquaponic system in greenhouses which can recycle and reuse the water and nutrients is gaining importance across the world to counter the uncertainties due to weather fluctuations. However, there is a slow pace of growth in aquaculture practices around the globe in general and India in particular. There are many barriers to adopt the aquaponic culture. In this study an analysis of the barriers for aquaponics culture in Indian context during the COVID-19 period is presented. Literature review and interactions with various stakeholders help to find out the list of potential factors while gauging the success of their prospective aquaponics project. The "best-worst" methodology (BWM) is employed for ranking of barriers, whereas categorizing of barriers is carried out with the help of fuzzy DEMATEL. Furthermore, the results of this research work are of great value to corporations or start-up companies looking to invest in this technology as well as to farmers who wish to adopt this farming technique. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic is an extreme event. Lockdown in India, in a bid to slow down the pandemic, helped in reducing air pollution levels of major industrial cities (60-70%), due to significant improvement in the air quality index. This has also contributed in reducing global carbon emissions and greenhouse gas emissions. There has been a 40-50% improvement in the riverine water quality in terms of dissolved oxygen, biological oxygen demand, coliform bacteria levels and suspended particulate matter. These short-term environmental benefits may even pose larger threat to the environment during the post-lockdown 'as usual scenario'. Due to lockdown, agriculture and aquaculture sectors have also been severely affected. Delayed harvesting in aquaculture negatively impacted the production cost, water productivity and footprint, total water use and water use efficiency. The COVID-19 crisis has shown the vulnerability of regional to global systems in protecting our health, environment and economy. Further, this pandemic has forced us to re-examine our relationship with nature for better association. Since COVID-19 has a possibility of becoming 'just another endemic', we must learn to live with this pandemic. [ABSTRACT FROM AUTHOR]

The disease outbreaks in aquaculture system of wetlands are the major cause of fish mortality. Among various bacterial septicaemic diseases, fish mortality caused by Acinetobacter spp. is recently reported in different fish species. Fish disease outbreak was investigated in a wetland of West Bengal, India to identify the aetiological factors involved. The moribund fish were examined and subjected to bacterial isolation. Two bacterial causative agents were identified as Acinetobacter junii and Acinetobacter pittii by biochemical characterization and 16S rRNA gene amplification. Both the isolates were oxidase‐negative, nitrate‐negative, catalase‐positive and indole‐negative. The molecular identification using 16S rRNA gene sequencing and phylogenetic tree analysis further confirmed the two Acinetobacter spp. with 97%–99% similarity. The antibiotic resistance patterns of these two bacteria revealed that both of them were resistant to β‐lactam, cefalexin, cephalothin, amoxyclav, cefuroxime, cefadroxil, clindamycin, vancomycin and penicillin. In addition, A. pittii was also resistant to other antibiotics of cephams group such as ceftazidime and cefotaxime. In the challenge experiment, both A. junii and A. pittii were found to be pathogenic with LD50 of 1.24 × 105 and 1.88 × 107 cfu/fish respectively. Histopathological examination of gill, liver and kidney revealed prominent changes supporting bacterial septicaemia. The investigation reports for the first time on concurrent infection by A. junii and multidrug‐resistant (MDR)‐A. pittii as emerging fish pathogens to cause severe mortality in Labeo catla and Hypophthalmichthys molitrix in a freshwater wetland. [ABSTRACT FROM AUTHOR]

Wild collected orange-spotted grouper were domesticated in Recirculating Aquaculture Systems (RAS) and sea cages for fish breeding. While breeding, viral nervous necrosis (VNN) infection was observed in both the systems after 18 months of domestication. Out of 50 domesticated broodfish used in the study, 11 (22%) fishes were found positive for VNN examined by reverse transcriptase polymerase chain reaction (RT-PCR) method. Quantitative real-time PCR (qPCR) study also confirmed the presence of VNN in the suspected fish, and detectable amount of virus copy number was observed in the brain, optic nerve, caudal fin, muscle, and gills. Analysis of the isolated viral gene sequence from the fish was closely related to the red-spotted grouper nervous necrosis virus (RGNNV) genotype and suggests that the isolates are probably endemic to Indian coast. The study also indicated that the sub-adults of orange-spotted grouper infected in the wild and remained as carrier during domestication and subsequently disease outbreak has occurred when water temperature was increased in culture environment. This is the first report on VNN in orange-spotted grouper broodstock from India. The results of the study illustrated that large population of the wild marine fishes are sub-clinically infected with betanodavirus and therefore, early detection of the disease should be adopted as best management practices in breeding for sustainable aquaculture development of the species. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a serious global threat driven by the overuse of drugs in humans, animals, as well as the contamination of natural environments with antimicrobial residues. In recent years, the rise of community-acquired infections resistant to antibiotics has drawn renewed attention to the environmental compartment, in particular for pathogens found in aquaculture systems. We quantified the prevalence of antibiotic resistance in Vibrios isolated from the Cochin Estuary as well as the adjoining shrimp farms, and seafood from markets. A total of 280 Vibrio strains were subjected to antimicrobial susceptibility testing and screened for the presence of blaTEM, blaCTX-M, and blaNDM-1 genes. All strains identified were resistant to at least three antimicrobials, and the percentage of drugs resistant per strain ranged from 16% up to 60%. All the strains from the estuary were resistant to amoxicillin, ampicillin, cephalothin, and colistin. Similarly, strains isolated from seafood were resistant to enrofloxacin, furazolidone, and trimethoprim, and all strains from shrimp farms were resistant to colistin. Plasmid-mediated antibiotic resistance was observed in 21% of the strains. In addition, the presence of blaNDM-1 gene was confirmed in 22.85% of the strains. The presence of multiple resistant phenotypes in vibrios, including resistance to last-resort compounds in domestic food sources, raises serious concerns for public health in the Cochin Estuary. Although localized in nature, our findings also have vital implications for the spread of AMR internationally, given the prominence of South India for seafood exports. [ABSTRACT FROM AUTHOR]

Vibrio vulnificus , Vibrio parahaemolyticus and Vibrio harveyi are the causative agents of the most severe diseases of marine and brackish aquaculture systems. These are also associated with serious ailments in humans. The present paper unravels the virulence features/genes and antimicrobial resistance (AMR) phenotypes/genes of these Vibrio spp. isolated from natural disease outbreaks of marine/estuarine fishes of India for the first time. Results on virulence features showed that V. vulnificus infected fish can pose public health risk. While, it has been found clinically that V. parahaemolyticus without tdh and trh genes are pathogenic to fish, even though they are reported to be, not associated with human diseases. It was significant to note that virulence features of V. harveyi were induced at increased salinity. Analysis based on the percentage prevalence of susceptible isolates and variation coefficient of zone diameters categorized 17 antibiotics in terms of their efficiency against each fish pathogenic species. Multiple antibiotic resistance index (MARi) of the isolates ranged between 0.058 and 0.47. Results on MARi and percentage of multidrug resistance strains indicated that >50% of the isolates were from low antibiotic usage area. The study generated tetH sequence from V. parahaemolyticus for the first time, and the sequence revealed high identity to that of clinical strains. Presence of tetB/ tetH gene was identified as the predictor for the resistance against the first generation tetracycline, the most commonly used antibiotic against Vibrio spp. in aquaculture practices. The data on associations between AMR features predicted certain cross-resistance between antimicrobials within Vibrio spp. Altogether, the paper serves as the baseline for epizootic tracking of public health significant vibrios from diseased fishes, to devise practical guidelines for antibiotic use and to formulate efficient control measures against three Vibrio spp. in aquaculture, targeting final applications in the implementation of national green and healthy aquaculture practices. • Helps to devise control measures against three pathogens of aquaculture practices. • Data for epizootic tracking of public health important vibrios from diseased fishes. • First report on antibiotic categorization based on activity against fish pathogens. • Shows predictor genes for 1st generation tetracycline resistance in fish pathogens. [ABSTRACT FROM AUTHOR]

Farmed tilapia fish has well recognized potential industries in producing rich proteinous food to reach global population worldwide. Significance of tilapia is relatively resistant to number of diseases and is the second most important group of farmed fish worldwide, with the production of more than 2.5 million tons annually. Unfortunately, mass mortalities of Tilapines were caused by Tilapia lake virus (TiLV) in Israel, Thailand, etc. of around 15 countries including India. In the present study, we had observed vast die-off of tilapia fishes in Katpadi Lake, Vellore, Tamil Nadu, India with the clinical signs of TiLV which includes scale protrusion, swelling of eye balls, reddish skin and abnormalities in swimming behavior. The infected tissue samples of the tilapia were screened against TiLV by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and histopathological analysis. RT-PCR results revealed the infection of TiLV in the fishes of Katpadi Lake and histopathological analysis of H & E staining had shown giant cells and multiple nucleic in liver as well as the presence of inclusion bodies. Our diagnostic studies conclude that the suspected fishes of Katpadi Lake were promptly infected with TiLV in farmed fish culture. [ABSTRACT FROM AUTHOR]