Use of therapeutants

Fisheries and Oceans Canada makes information available to the public on the annual use of therapeutants at marine finfish aquaculture facilities in British Columbia. This information is compiled jointly by DFO and the B.C. Ministry of Agriculture, which monitors the manufacture of all medicated feeds milled for finfish.  

Many farmed finfish populations of B.C. are not fed antibacterial products. When necessary, any drug used in food fish in B.C. is applied according to a veterinary prescription. In the presence of a bacterial infection, medications are prescribed as needed to minimize, and often to mitigate, disease events that may arise seasonally or following a stressful event.   

The approved antibacterial drugs for finfish in Canada include: oxytetracycline, florfenicol, trimethoprim in combination with sulfadiazine, or ormetoprim in combination with sulfadimethoxine. Additional approved drug products are available at the discretion of prescribing veterinarians but the use of alternative drugs is uncommon. The graphs below present annual aggregate totals of all antibacterial agents in medicated feeds.  Although the dosage of each drug differs, aggregate totals allow a broader view and general trend of antibacterial use in salmon production.   

The  general decline seen in antibacterial use despite increased salmon production is not unique to B.C. – this situation is also seen in other salmon farming regions of the world, and is attributed to the introduction of more effective vaccines for bacterial diseases and other advances in health management.  

About the graph

Annual antibacterial drug use is noted as grams of active antibacterial per tonne of salmon produced (as opposed to amount of drug administered). These values also include the antibacterials fed to broodstock populations (non-food fish).

Graph: Antibacterial Use vs. Aquaculture Salmon Production in B.C. From 1995 to 2014

The blue line (or denominator) in the 1995-2012 bar chart, tonnes of salmon produced, is a calculation (using annual harvest statistics from BC’s cultured salmon fishery). The B.C. Ministry of Agriculture (BCMA) receives ‘dressed harvest’ data from DFO files and BCMA converts those harvest volumes back to a best estimate of living swimming biomass, or round weight, of salmon (both Atlantic and Pacific) as harvest begins. This has been the historical approach to facilitate the B.C. Seafood Industry – Year in Review report.