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 BC Ministry of Agriculture, which monitors the manufacture of all medicated feeds milled for finfish.

Use of antibacterials

Use of antibacterials at BC marine finfish aquaculture sites

The graph below presents annual aggregate totals of all antibacterial agents in medicated feeds. Although the dosage of each drug differs, aggregate totals allow a broader view of antibacterial use in salmon production.

Despite increased salmon production, there has been a general decline in antibacterial use in BC and in other salmon farming regions of the world. This is attributed to the introduction of more effective vaccines for bacterial diseases and other advances in health management.

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).

The blue line denotes tonnes of salmon produced and is calculated using annual harvest statistics from BC's cultured salmon fishery.

Graph: Antibacterial Use vs. Aquaculture Salmon Production in BC From 1995 to 2015
Long text version
Year Grams of active antibacterial per tonne of salmon Round weight of salmon produced (tonnes x 103)
1995 456 27
1996 336 28
1997 516 37
1998 383 44
1999 263 49
2000 342 49
2001 165 68
2002 242 85
2003 350 73
2004 337 62
2005 227 71
2006 106 78
2007 109 79
2008 68 81
2009 67 76
2010 73 79
2011 42 83
2012 69 74
2013 80 77
2014 88 62
2015 155 92
Use of SLICE®

Use of SLICE® at BC marine finfish aquaculture sites

Graph: Use of in-feed anti-lice therapeutants in BC salmon aquaculture
Long text version
Year Ivermectin Emamectin Benzoate
1996 0.02 0
1997 0.012 0
1998 0.009 0
1999 0.002 0
2000 0.005 0.049
2001 0.0001 0.063
2002 0 0.104
2003 0 0.101
2004 0 0.166
2005 0 0.263
2006 0 0.204
2007 0 0.137
2008 0 0.203
2009 0 0.159
2010 0 0.266
2011 0 0.263
2012 0 0.186
2013 0 0.226
2014 0 0.332
2015 0 0.334

The graph above shows the use of ivermectin and emamectin benzoate, the two in-feed anti-lice therapeutants that have been used in BC salmon aquaculture.

The prescription drug ivermectin was discontinued after the year 2000, when emamectin benzoate, the active chemical of the in-feed product commercially known as SLICE, became available. SLICE has been approved by Health Canada and is deemed to present little risk to the health of fish, humans and the environment. It is administered to farmed fish under veterinary prescription. At this time, SLICE is the only practical and available in-feed drug to manage sea lice on farmed salmon in BC.

In 2004 and 2005, Atlantic salmon production rose dramatically in BC and production of Pacific salmon species declined. Because Atlantic salmon are less resistant to lice infection than their Pacific counterparts, the amount of therapeutant per tonne of production used to control lice increased.

As illustrated, average use of emamectin benzoate has remained fairly stable since 2004, at about 0.2 grams per tonne.

Government and salmon producers are working towards a more sustainable Integrated Pest Management Approach to sea lice management in BC. This will emphasize area-based management and permit the use of alternative tools, such as low-risk bath techniques, to manage sea lice in aquaculture facilities while protecting adjacent ecosystems and species.