This report provides a summary of fish health events reported by aquaculture companies to Fisheries and Oceans Canada (DFO). A fish health event is any suspected or active disease that occurs within an aquaculture facility that requires the involvement of a veterinarian and warrants mitigation measures (e.g., treatment, quarantine, reduction in density). As a condition of licence, company veterinarians must notify DFO within seven days of any fish health event on a farm and provide a preliminary or confirmed farm-level diagnosis as well as details on any sampling, monitoring or mitigation measures planned or performed. Historical data are available from 2016 to the present. Prior to this time, fish health event reporting was not required by conditions of licence. The terminology used in the report’s column headings is defined in the terminology file below. Related links: + Infographic: [Monitoring fish health from hatchery to harvest](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/hatchery-ecloserie-eng.html) + Infographic: [How DFO inspects fish health at BC aquaculture sites](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/health-sante-eng.html)

Mortality at salmon aquaculture facilities is closely monitored. As in any population of wild or farmed animals, there are a number of causes leading to death. While in-depth diagnostic testing takes time, carcasses are routinely assigned to a number of defined categories which can help facility operators and Fisheries and Oceans Canada staff quickly assess whether disease may be present. Facility operators report mortalities in a number of categories that describe either the cause of death or the condition of the carcass. This report provides a breakdown of mortality by carcass category for each active facility. Sites used exclusively for smolt entry may have elevated mortality due to stresses associated with initial seawater entry. Similarly, elevated mortalities may occur if fish are stressed due to harvest activities. If mortalities at a facility exceed thresholds defined by conditions of licence, a “Mortality Event” occurs. Details of individual mortality events associated with high monthly mortalities reported here can be found in the [Mortality events at British Columbia marine finfish aquaculture sites](https://open.canada.ca/data/en/dataset/7fbb2662-391a-4df7-99b4-3343fa68fc93) report. Related links: + Infographic: [Monitoring fish health from hatchery to harvest](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/hatchery-ecloserie-eng.html) + Infographic: [How DFO inspects fish health at BC aquaculture sites](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/health-sante-eng.html)

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. Fisheries and Oceans Canada (DFO) applies a computerized selection system to randomly select active salmon farms within the fish health zones of the British Columbia. 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 percent of the farms then 30 percent of the farms selected for audit would be randomly chosen from that area. This ensures equal probability of each farm being selected for sampling. To ensure confidence in the sample results, Fisheries and Oceans Canada endeavours to conduct fish health audits at 30 active farmsites per quarter, or approximately 120 each year. Farm audits are conducted in conjunction with the farm’s regularly scheduled carcass collection, allowing Fisheries and Oceans Canada staff access to the freshest of the dead fish. This approach of targeted disease sampling on recently dead fish increases the likelihood of DFO veterinarians finding disease, if present, and attributing an accurate “cause-of-death” diagnosis to each carcass gathered. The summary tables are updated quarterly to reflect Fisheries and Oceans Canada’s fish health monitoring activities. For the purpose of fish health monitoring, a site is considered “active” if the facility holds any salmonid for at least 30 days, and has a minimum of three fully stocked pens during the quarter in which sampling is to occur.

Fisheries and Oceans Canada’s (DFO’s) Conditions of Licence for finfish aquaculture include requirements to minimize harm to wild fish that swim into facilities. Facility operators must also maintain an incidental catch log, which is a record of wild fish caught at the facility during harvest and transfer events. This information is submitted to DFO and public reports are posted quarterly. The tables provided list the reported incidental catch of dead wild finfish and the year and month in which they were captured from B.C. marine finfish facilities during harvest and transfer events. Data are reported in the quarter in which the harvest activities ended and will not exist for farms that do not have fish on site or where no incidentally caught fish were recorded.

Fisheries and Oceans Canada requires operators of active marine finfish aquaculture sites in British Columbia to monitor for benthic (seabed) impacts. The benthic monitoring program is designed to limit the location, area and intensity of impact created by fish farms to the seabed and to support sustainable aquaculture by maintaining healthy ecosystems. All operational sites must be monitored at peak production, when the greatest environmental impact is most likely to occur. If the thresholds outlined in Aquaculture Activities Regulations are exceeded, the site must be fallowed (left empty) until further monitoring shows the seabed has sufficiently recovered. Fisheries and Oceans Canada assesses industry reports and video data for compliance and uses the data to better understand benthic impacts. See [Results of DFO benthic monitoring audits of BC marine finfish aquaculture sites](http://open.canada.ca/data/en/dataset/c1a54a0c-4eb0-4b50-be1f-01aee632527e "Results of DFO benthic monitoring audits of BC marine finfish aquaculture sites"). Related links: + Infographic: [Monitoring benthic impacts at BC aquaculture sites](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/benthic-benthique-eng.html) + Graph: [Benthic performance at marine finfish aquaculture sites in BC](http://www.pac.dfo-mpo.gc.ca/aquaculture/reporting-rapports/benth/index-eng.html)

This report provides summary fish health data collected by Fisheries and Oceans Canada (DFO) from randomly selected licensed marine facilities culturing salmon in British Columbia (BC). Results of polymerase chain reaction (PCR) screening are provided, as well as a list of the bacterial pathogens isolated by culture, and whether a pathogen or disease has been confirmed by histopathology (microscopic examination). DFO veterinarians provide a farm-level diagnosis and identify any conditions of note based on these laboratory findings and any other information collected during the fish health audit or reported by companies as a condition of licence. The terminology used in the report’s column headings can be found in the terminology file below. DFO Science is engaged in numerous active research projects examining issues such as fish diseases, wild-cultured species interactions and habitat impacts related to aquaculture. Information on some of these projects, as well as on aquaculture research occurring in other regions, is available on our [website](http://www.dfo-mpo.gc.ca/aquaculture/science-eng.html"website"). Related links: + Infographic: [Monitoring fish health from hatchery to harvest](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/hatchery-ecloserie-eng.html) + Infographic: [How DFO inspects fish health at BC aquaculture sites](http://www.dfo-mpo.gc.ca/aquaculture/publications/infographics-infographie/health-sante-eng.html)

These data are a compilation of geographically widespread observations of premature mortality in Pacific salmon across their range in Alaska in 2019. Premature mortality observations primarily spanned an area of western and southcentral Alaska that is approximately one million km2 and included all five species of Pacific salmon. Observations were obtained and compiled in a single database from four sources including reports to a citizen science reporting network (LEONetwork.org), from Alaska Department of Fish and Game's Arctic-Yukon-Kuskokwim region by community members or staff, traditional media and social media, and directed emails by the lead author. Occasional observations of species other than Pacific salmon were obtained during this effort and were included in the database.

These data are a compilation of geographically widespread observations of premature mortality in Pacific salmon across their range in Alaska in 2019. Premature mortality observations primarily spanned an area of western and southcentral Alaska that is approximately one million km2 and included all five species of Pacific salmon. Observations were obtained and compiled in a single database from four sources including reports to a citizen science reporting network (LEONetwork.org), from Alaska Department of Fish and Game's Arctic-Yukon-Kuskokwim region by community members or staff, traditional media and social media, and directed emails by the lead author. Occasional observations of species other than Pacific salmon were obtained during this effort and were included in the database.

Fisheries and Oceans Canada requires operators of active marine finfish aquaculture sites in British Columbia to monitor for benthic (seabed) impacts. The benthic monitoring program is designed to limit the location, area, and intensity of impact created by fish farms to the seabed and to support sustainable aquaculture by maintaining healthy ecosystems. In addition to the monitoring and reporting required of licence holders, DFO staff biologists conduct field audits to collect and assess sediment samples and take video of the seafloor. This information is used to determine compliance and learn more about benthic impacts during different times of the production cycle. Further review and action may be required for sites with poor environmental performance or issues with non-compliance. For the results of benthic monitoring activities conducted by the industry, see [Results of industry benthic monitoring of BC marine finfish aquaculture sites](http://open.canada.ca/data/en/dataset/7e76fdc8-c36a-491a-9afb-4f9280c929e8 "Results of industry benthic monitoring of BC marine finfish aquaculture sites"). Related links: + Infographic: [Monitoring benthic impacts at BC aquaculture sites](https://www.dfo-mpo.gc.ca/about-notre-sujet/publications/infographics-infographies/benthic-benthique-eng.html) + Graph: [Benthic performance at marine finfish aquaculture sites in BC](http://www.pac.dfo-mpo.gc.ca/aquaculture/reporting-rapports/benth/index-eng.html)

Fish health on British Columbia salmon farms is managed throughout the production cycle to maintain healthy fish populations and to identify and address disease occurrences as soon as they arise. Aquaculture licence conditions set out mandatory monitoring and reporting requirements to ensure any potential impacts are appropriately mitigated at salmon farms. A central component of on-farm fish health management is a Fish Health Management Plan (FHMP). FHMPs are approved by Fisheries and Oceans Canada (DFO) and describe the fish health principles that the licensee must follow to maintain fish health and biosecurity at the farm. Both DFO and aquaculture companies have veterinarians on staff (or available on contract, for some companies) to monitor fish health on farms. Company veterinarians oversee routine health screening and ensure appropriate husbandry in day-to-day operations and identify appropriate management measures if fish health concerns arise. Licence holders must routinely submit a variety of fish health data to DFO. Routine reports include monthly sea lice abundance, antimicrobial use and information on [mortality rates](https://open.canada.ca/data/en/dataset/85986a45-b71d-4380-8990-d5763fdf19a5"mortality rates"), including the suspected [cause of mortality](https://open.canada.ca/data/en/dataset/0a8c5505-ecb3-4d8b-8120-462bd7def6bb"cause of mortality"). Additional reports are submitted if there are elevated mortalities, a fish health event that requires the involvement of a veterinarian or sea lice abundance over the DFO determined threshold. Through the Fish Health Audit and Surveillance Program, DFO oversees the health of cultured salmon to minimize fish health and disease risks to wild and farmed fish and publishes [reports](http://www.pac.dfo-mpo.gc.ca/aquaculture/regs-eng.html"reports") on regulation and monitoring of BC’s marine finfish aquaculture facilities. Sites are [routinely inspected](http://www.pac.dfo-mpo.gc.ca/aquaculture/reporting-rapports/health-compliance-conform-sante/index-eng.html"routinely inspected") to ensure compliance with licence conditions and FHMPs, to verify the accuracy of industry reporting, and to collect samples for [independent](https://open.canada.ca/data/en/dataset/6c891715-317c-4d4d-9fe8-ea425e01d9d2"independent") fish health and disease screening. All salmon aquaculture transfers require authorization under section 56 of the Fishery (General) Regulations. Movements of fish to and from farms may be required to introduce new stock, facilitate growth at different life stages or optimize production. All transfer applications are accompanied by a signed veterinary attestation which details the health status of the fish to be transferred and attests to their health. DFO reviews these applications to determine whether the movement may adversely affect local aquatic species and habitats. DFO veterinarians and biologists assess the information gathered by DFO audits and inspections, as well as that submitted by industry to gain a complete picture of the health status of the fish to be moved. Occasionally a fish health concern will be identified during the review conducted by DFO fish health staff. Most often, clarification with the industry’s fish health staff will be sufficient to address the concern; however occasionally additional mitigative measures are deemed necessary to address potential risks. Animal welfare and ensuring humane treatment of the fish are an important consideration when choosing the most appropriate mitigation option. Common mitigation measures include: • Pre-transfer grading to select the healthiest fish within the age class • Humane culling to remove affected fish or “poor performers” that are most likely to harbour disease or unlikely to ingest medicated feed. Poor performers are fish that fail to thrive, stop or reduce feeding, and may be emaciated (long and skinny). There are various reasons a fish becomes a poor performer, including failure to adapt to salt