Fish Health Management in the Pacific Region

As the regulator of the aquaculture industry in B.C., Fisheries and Oceans Canada (DFO) is committed to protecting the health of farmed and wild fish stocks.

Under the Conditions of Licence for Finfish Aquaculture, licence holders for salmonid species are required to develop and implement a Health Management Plan (HMP). The HMP is designed to encompass all aspects of farming that can affect the health of the animals within the aquaculture facility, and to minimize any potential impact on the health of the surrounding ecosystem.

Among other things, a HMP lays out the protocols in place to ensure aquaculture fish are monitored for signs of disease and infection. It includes protocols for keeping fish healthy, monitoring fish health and euthanasia, as well as procedures to record and store fish health information, and special considerations for sites holding broodstock. Each aquaculture facility has designated staff to oversee and assess the health status of its fish, and is responsible to provide this information to DFO.

Like all animal populations, fish are susceptible to a variety of diseases and infections. As diseases may spread naturally via water, farmed fish can be infected by diseases borne by wild fish and vice versa. Fish health professionals use their knowledge of wild fish migratory patterns to anticipate outbreaks of disease within farmed stocks, which often serve as ‘sentinels’ of the marine ecosystem, and to minimize the risk of disease transfer from farmed to wild stocks. Vaccines are administered to hatchery fish to enhance immunity and provide protection while in the marine environment.

Most diseases and infections arising in farmed fish can be controlled. Occasionally in-feed medications are prescribed by attending veterinarians. All treatments and vaccines used have been extensively studied and tested before being approved for use in Canada, and pose no risk to humans consuming farmed fish.

While the majority of fish health concerns are easily remedied, the Health of Animals Act lists a number of serious infectious diseases that must be reported immediately to the Canadian Food Inspection Agency (CFIA). When these diseases are reported, CFIA conducts an investigation to verify the presence of the disease, and works with the implicated authorities to develop an appropriate plan to deal with the disease and to prevent its spread.

One of these diseases, infectious salmon anaemia (ISA) is of particular concern to Atlantic salmon, and both industry and DFO test extensively for its presence in B.C. From 2003 to 2010, prior to DFO becoming the regulator of the aquaculture industry in B.C., the B.C. Ministry of Agriculture and Lands operated a scientifically designed surveillance program that tested over 4,700 farmed salmon in B.C. for ISA. No confirmed case of ISA has ever arisen in B.C., in either farmed or wild fish. Research and disease monitoring continue.

DFO’s Fish Health Program in B.C.

DFO Aquaculture Management staff oversee the aquaculture industry, and departmental fish health professionals are responsible for ensuring that aquaculture licence holders are complying with their HMP. The objective of DFO’s Fish Health Program in B.C. is to monitor and minimize the potential risks of disease and disease transmission both to and from farmed fish, and to ensure that aquaculture health management in B.C. is held to an exceptionally high standard.

Facility operators are required to regularly report on the health of their stocks. These reports are reviewed by veterinarians in DFO’s Aquaculture Management team to assess whether appropriate measures are being taken to protect the health of the fish, and to detect any potentially serious diseases as early as possible.

In addition to reviewing reports submitted by industry, Aquaculture Management staff conduct regular inspections of finfish facilities under the Fish Health Audit and Surveillance (FHAS) component of the Fish Health Program. It is mandatory for aquaculture licence holders to provide DFO staff with access to fish carcasses for sampling.

During a fish health inspection, Aquaculture Management staff review the following activities, protocols, procedures and plans to develop a clear picture of the health status of the fish on each site:

• Biosecurity
• Feed, nutrition and medication
• Monitoring water quality
• Fish health - carcass retrieval protocols
• Fish health/husbandry records
• Sea Lice – handling procedures
• Fish handling, euthanasia, welfare
• Disease outbreak/kill contingency plan

Fish health audit and surveillance activities consist of three main tasks:

1. DFO fish health veterinarians and bio-technicians monitor activities and review health-related records at marine salmon farms, as outlined in HMPs and verified using a compliance inspection checklist;
2. DFO fish health bio-technicians collect samples from recently dead “silver” carcasses to verify, or audit, the farm veterinarians’ routine monitoring and reporting of natural diseases that are common to B.C.’s wild and farmed fisheries, and;
3. DFO audit results are compared to reports submitted directly to DFO by the farming companies each calendar quarter.

In the course of its surveillance activities, DFO tests for specific federally and internationally recognized diseases and pathogens that may affect fish movement and trade.

Samples are pooled and screened using state-of-the-art and internationally accepted Polymerase Chain Reaction (PCR) techniques for the following pathogens:

• Infectious Hematopoietic Necrosis Virus (IHNv)
• Infectious Pancreatic Necrosis Virus (IPNv)
• Infectious Salmon Anaemia Virus (ISAv)
• Viral Hemorrhagic Septicaemia (VHSv North American strain IVa)
• Piscirickettsia salmonis

On average, five to eight of the “fresh silver” carcasses are selected for standard histopathology, bacteriology, and molecular diagnostics / virology. Samples are sent to the provincial Animal Health Centre in Abbotsford for extensive evaluation. The Centre is an American Association of Veterinary Laboratory Diagnosticians accredited full-service diagnostic laboratory. The use of an accredited laboratory provides confidence in the diagnostic results due to the high standards of quality assurance and quality control.

Selecting salmon farms for audit

For health auditing purposes, a farm is considered active once three pens of fish have been present for 30 days, following entry of the first pen of fish at the farm. DFO applies a computerized, multistage selection system to randomly select active salmon farms within the fish health zones of the B.C. coast. All farms within a zone are assigned a random number and a computer selection of the farms within that zone is weighted (based on the fish species and the number of “active farms” operating in that zone as a percentage of the total number of active farms in the province). In other words, if a zone contains 30 per cent of the farms then 30 per cent of the farms selected for audit would be randomly chosen from that area. This ensures equal probability of each farm being selected for sampling. For reasons of practicality and resources, the maximum sample size is 30 farms audited per quarter. The aim is to complete 120 farm audits each year which ensures that all farms in B.C. have equal opportunity to be sampled within a year. Farm audits are conducted in conjunction with the farm’s regularly scheduled carcass collection, allowing DFO staff access to the freshest of the dead fish. This approach of targeted disease sampling on recently dead fish increases the likelihood of veterinarians and DFO finding disease and attributing a ‘cause-of-death’ diagnosis to each carcass gathered.

The table below provides a summary of DFO’s fish health monitoring and surveillance program activities in B.C. to date.

In the future, fish health data gathered through DFO’s Fish Health Program will be made available on this website. 

• DFO's Fish Health Monitoring Activities 2011