Interactive effects of carbendazim and cold shock on haematology and behaviour of juvenile Labeo rohita

Fungicides, including carbendazim, are prevalent agricultural pesticides that contaminate surface waters, posing a threat to aquatic organisms like fish. The study addresses a critical knowledge gap regarding the mechanistic effects of carbendazim toxicity in fish, especially its influence on cold shock response, a major concern in aquaculture, particularly in the Indian subcontinent where winter fish mortality is common. This research investigates the impact of carbendazim exposure on juvenile Labeo rohita (rohu), an economically important carp species, focusing on health, behaviour, and cold shock response. The 96-h LC50 of carbendazim was determined, and haematological and behavioural responses were measured in fish exposed to carbendazim, both independently and in conjunction with cold shock. The 96-h LC50 of carbendazim for rohu juveniles was found to be 2 mg L−1. Sub-lethal carbendazim exposure induced behavioural and physical abnormalities. Sub-lethal exposure to carbendazim also significantly impacted the ability of rohu to withstand cold shock. The research has important implications for aquaculture management and pesticide regulation, particularly in regions where carbendazim use is high and cold stress is a recurring issue.