A Novel Risk-Based Quantifiable Approach to Biosecurity Measures in Biofloc Units of West Bengal, India: Implications for Consumer Safety

Abstract

A novel risk-based weighted scoring system was developed taking the risk of biosecurity measures of each biofloc technology (BFT) unit in two aquaculturally influential districts, North and South 24 Parganas, West Bengal, India, into account. The current study was carried out over a 6-month period to observe the incidence of Aeromonas veronii and Escherichia coli in biofloc units of these districts along with a questionnaire-based survey on biosecurity measures employed there. Moreover, the correlation between the total heterotrophic bacterial counts (THBCs) in water and gut with the physicochemical parameters of water was also analyzed. The physico-chemical parameters of water in the BFT units were maintained optimally for Nile tilapia culture. A significant positive correlation was observed between the THBCs of water samples and the dissolved oxygen (DO) of Panchpota unit, whereas a significantly negative correlation was observed between the THBCs of water and gut samples collected from Basirhat and Ashoknagar units. The prominence of E. coli in biofloc units of South 24 Parganas suggested possible faecal contamination and lower biosecurity measures being im-plemented implying at the threats of consumer safety. The grading system, on the other hand, might be viewed as a beneficial instrument for monitoring the biosecurity level of biofloc units over time and pointed out that West Bengal biofloc farmers paid more heed to internal biosecurity than external biosecurity measures.