Fish Health Management
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.
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. Occasionally in-feed medications are prescribed by attending veterinarians to treat diseases and infections that arise in farmed fish. 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), the lead federal authority responsible for monitoring issues related to the health of farmed fish and terrestrial animals. 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 government monitor extensively for its presence at aquaculture facilities and in wild salmon stocks. In recent years, over 5000 fresh, properly collected and stored samples have been tested and no case of ISA in British Columbia salmon has ever been confirmed.
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 Health Management Plan. 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.
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:
- 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:
- 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;
- 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;
- 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. These diseases can severely impact fisheries and affect regional and national trade so they warrant urgent notification and immediate attention. While some of these diseases and pathogens are considered exotic to B.C., others are known to exist naturally within the local ecosystem.
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.
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