Mortality events graph

These figures provide an annual break-down of the cause of mortality events occurring at marine finfish facilities in British Columbia. In some cases, more than one event may occur at a single facility in a calendar year.

Low levels of mortality normally occur in any large population of animals. If mortality surpasses thresholds outlined in Fisheries and Oceans Canada’s (DFO’s) conditions of licence for marine finfish aquaculture, this considered to be a Mortality Event. Companies are required to report all mortality events to DFO, to mitigate appropriately to prevent continued mortality, and to minimize risk to wild fish and the environment, including proper containment and disposal of dead fish.

DFO biologists and veterinarians review all reported events and work closely with industry staff and veterinarians to ensure that appropriate management strategies are implemented. DFO biologists and veterinarians may also visit the site to confirm reports through record review, inspection of facilities, sampling of fish, and protocol verification.

Predation

Mortality as a result of predation by wild animals, usually seals and sea lions. Licence holders protect farmed fish from predation through mitigation techniques such as predator netting (an extra net around the entire system) or electric fences. Acoustic deterrants are not permitted.

Physiological

Includes mortalities due to poor sea water aclimation of smolts upon ocean entry or early maturation of adult fish.

Environmental

Physical events such as algae blooms, low dissolved oxygen, or other naturally occurring water quality conditions that cause mortality to farmed salmon. Some events can be mitigated by deploying air diffusers to supply additional oxygen to farmed fish, or to create a “wall” of air bubbles that prevents harmful algae from entering the system.

Mechanical

Farmed fish are often subject to stressful procedures such as transport, harvest or treatment events that result in mortalities. The mortality events are often associated with human error or environmental conditions that make fish more susceptible to stress.

Disease

Includes mortality events as a result of a veterinarian diagnosed disease. Some diseases, such as fungal infections or environmentally induced diseases, do not require treatment and often resolve naturally. Other diseases require mitigation in the form of antibiotics or harvesting. In extreme cases, or where risk to wild fish is a concern, culling may be the chosen mitigation. When veterinary intervention is required, an additional Fish health event must also be reported, as per Conditions of Licence.

Other

In some instances, farmed fish experience mortality due reasons that do not fall within the categories mentioned above. These mortality events are often associated with unusual events that can harm fish such as system failures, storms or strong tides.

Detailed information on specific mortality events can be found in the report Mortality events at British Columbia marine finfish aquaculture sites.

2023

Mortality events at marine finfish aquaculture facilities in British Columbia, 2023

Long text version

Number of facilities with events: 13

Number of Facilities with no events: 35

Number of mortality events: 15

Event category	Proportion of events
Predation	7%
Physiological	0%
Environmental	60%
Mechanical	13%
Disease	7%
Other	13%

2022

Mortality events at marine finfish aquaculture facilities in British Columbia, 2022

Long text version

Number of facilities with events: 28

Number of Facilities with no events: 33

Number of mortality events: 62

Event category	Proportion of events
Predation	0%
Physiological	0%
Environmental	26%
Mechanical	66%
Disease	8%
Other	0%

2021

Mortality events at marine finfish aquaculture facilities in British Columbia, 2021

Long text version

Number of facilities with events: 35

Number of Facilities with no events: 39

Number of mortality events: 85

Event category	Proportion of events
Predation	4%
Physiological	1%
Environmental	32%
Mechanical	60%
Disease	2%
Other	1%

2020

Mortality events at marine finfish aquaculture facilities in British Columbia, 2020

Long text version

Number of facilities with events: 44

Number of Facilities with no events: 33

Number of mortality events: 109

Event category	Proportion of events
Predation	1%
Physiological	0%
Environmental	42%
Mechanical	50%
Disease	6%
Other	1%

2019

Mortality events at marine finfish aquaculture facilities in British Columbia, 2019

Long text version

Number of facilities with events: 46

Number of Facilities with no events: 37

Number of mortality events: 83

Event category	Proportion of events
Predation	0%
Physiological	1%
Environmental	85%
Mechanical	28%
Disease	0%
Other	1%

2018

Mortality events at marine finfish aquaculture facilities in British Columbia, 2018

Long text version

Number of facilities with events: 40

Number of Facilities with no events: 40

Number of mortality events: 77

Event category	Proportion of events
Predation	0%
Physiological	0%
Environmental	66%
Mechanical	19%
Disease	14%
Other	0%

2017

Mortality Events at marine finfish aquaculture facilities in British Columbia, 2017

Long text version

Number of facilities with events: 27

Number of Facilities with no events: 54

Number of mortality events: 42

Event category	Proportion of events
Predation	5%
Physiological	0%
Environmental	74%
Mechanical	21%
Disease	0%
Other	0%

2016

Mortality events at marine finfish aquaculture facilities in British Columbia, 2016

Long text version

Number of facilities with events: 24

Number of Facilities with no events: 57

Number of mortality events: 34

Event category	Proportion of events
Predation	0%
Physiological	0%
Environmental	85%
Mechanical	6%
Disease	9%
Other	0%