Factors Influencing Disease Dynamics in Small-Scale Carp Polyculture in Bangladesh

Small scale carp polyculture plays a key role for food supply in Bangladesh, however, factors including water pollution, limited infrastructure and inadequate disease management hinder its sustainability. This paper reports on a survey of 231 farmers across the 6 major carp producing regions in Bangladesh, analyzing factors including, farmers’ social aspects, farm characteristics, information on disease and approaches adopted to combat them, and biosecurity practices. Almost half (46.8%) of the farms surveyed experienced disease in carp species, with clear regional variations. Eighty four percent of farms reported carp mortalities during disease outbreak, with an average mortality level 10.23±11.81%. Clinical signs during outbreaks lasted between a week and a month, and there was a peak in disease outbreaks in two seasonal periods between June to July and October to December. Disease incidence was related to a range of factors including the farmer experience, ponds/farm type, stocked species, and biosecurity practice. A combination of disinfecting measures during pond preparation and measures during stocking, including discarding fingerling transport water off-farm, fingerling disinfection and check the health of fingerlings before stocking significantly reduced disease occurrence. Treatments involving the antibiotics, ciprofloxacin, erythromycin, and azithromycin were reported as ineffective, raising concerns about non-prudent use, inadequate dosing (perhaps without appropriate veterinary guidance) and the potential for further driving antimicrobial resistance in the environment. The research unveils a concerning pattern of disease high disease incidence across small-scale carp farms in Bangladesh and the significant potential for disease spread highlights the need for responsible disposal practices. The study emphasizes the need for improving training and awareness programs are vital for addressing biosecurity and disease management challenges, ensuring sustainable aquaculture and community well-being.