Environmental Impacts

Currently, BC has an average of over 85 open net-cage fish farms operating at any given time in our coastal waters.

There are presently 136 licensed farm sites but some will always be empty of fish, or “fallowed.” Despite occasional fallowing, industrial open net-cage farms create huge environmental impacts that will only increase if the industry continues to expand.


Salmon farming is one of the most harmful aquaculture production systems. The industry uses open net-cages placed directly in the ocean, where farm waste, chemicals, disease and parasites are released directly into the surrounding waters, harming other marine life. Escapes of thousands of farmed fish are common in this industry, as are the deaths of natural predators like sea lions and seals who are attracted to the pens of fish.

Raising carnivorous fish like salmon that require a high percentage of protein derived from wild fish in their feed also has a significant impact on the environment. More kilograms of wild fish are used to raise salmon than farmed salmon produced, depleting wild fish stocks rather than supplementing them.

The vast majority of salmon farming operations depend on the use of vaccines, antibiotics and pesticides to control disease and parasites that are often exacerbated by the high densities required to make industrial livestock operations profitable.

Learn more about each of these impacts by following the links below:

  • One of the most devastating impacts of salmon farming is the risk sea lice pose to juvenile wild salmon. Sea lice proliferate on salmon farms and spread to surrounding waters attacking baby salmon as they head out to sea. Learn more about the weight of scientific evidence documenting the impacts of sea lice on wild salmon.
  • When over half a million or more farmed salmon are penned in a small area, fish feces and waste feed can have a significant impact on the ocean bottom and surrounding ecosystems, especially in shallow waters or areas that do not flush well.
  • Despite regulations and management practices intended to limit farmed salmon escapes, escapes still happen in every salmon farming region in the world, BC included. Learn more about how escaped farmed fish compete with wild salmon for habitat and food.
  • Open net-cages attract natural fish-eating predators like seals and sea lions. Some of these marine mammals are shot by fish farmers that feel that the animals are a threat to their stock. Others become ensnared in the nets surrounding the open net-cages and drown. An untold number of seals, sea lions, dolphins and porpoises are killed annually by salmon farms. Learn more about marine mammal deaths.

Closed containment systems offer a promising solution to many of the problems created by open net-cage farming. Find out more about closed containment.