Survey findings of disinfection strategies at selected Norwegian and North American land-based RAS facilities: A comparative insight

Disinfection is an integral component of establishing effective biosecurity, through preventing pathogen introduction and transmission within and between aquaculture facilities. Nonetheless, there is a lack of documentation on aquaculture facility disinfection practices and strategies, thereby posing a challenge to benchmarking the current status and to determining optimal approaches. To gain a contemporary insight in this area, an internet-hosted survey was conducted for selected Atlantic salmon recirculation aquaculture (RAS) facilities in Norway (NO) and North America (NA, i.e., USA and Canada). The survey focused on the disinfection of materials and equipment in a RAS facility, and did not cover water disinfection. A total of nine facilities in NO and 16 in NA participated in the survey, which was conducted between Q2 and Q4 of 2018. Most of the responding facilities had standardised disinfection protocols (NO: 6/9; NA: 15/16); however, many respondents disclosed that their protocols had not been experimentally validated. The age of disinfection protocols was between 4 and 10 years old, with the majority of respondents regularly performing protocol appraisals. More than 80% of the facilities in both regions reported a compliance rate of 90–100%. Survey results indicated that peracetic acid-based disinfectants are the most commonly used chemicals in NO, while chlorine is predominant in NA. These disinfectants are used for the tanks and pipelines, floor, and ancillary equipment. In NO, the three topmost criteria when selecting a disinfectant were efficacy against pathogens, user safety, and ease of application. While efficacy and user safety are also prioritised in NA, it was also reported that threats of toxic residuals are also highly considered. Only one facility in NO and five in NA experienced a disease outbreak in the last 5 years. The survey responses presented the current state of aquaculture disinfection of representative land-based RAS facilities in both regions, and this information will be valuable in future benchmarking to develop robust and comprehensive disinfection strategies in salmon aquaculture.