Seawater Systems

After spending a year in freshwater, Atlantic salmon naturally swim out to sea to feed and grow. Aquaculture replicates this process by transferring salmon from the hatchery to specially designed and engineered sea cages in the ocean.

Salmon at the sea farms are continuously monitored with underwater cameras by trained Mowi personnel to enable efficient feeding processes, detect potential escapees, and to ensure appropriate fish health management practices are used.

After less than two years at sea, the salmon are harvested and transferred to fish processing facilities where they are prepared for markets in Newfoundland and Labrador and around the world.

Sea Cage Sites: Monitoring

Feeding, Behaviour, & Mortality​

Underwater cameras provide a constant view above and below water

  • Monitor feeding (reduce waste to ocean floor)
  • Monitor behaviour (stress, predators)
  • Monitor health (signs of parasites/disease, mortalities)

Fish Health

Surveillance Programs  are conducted by staff (daily, weekly) and both Mowi (monthly) and Provincial veterinarians (quarterly)

  • Daily, monthly, and quarterly monitoring for diseases (visual as well as bacterial sampling)
  • Weekly checks for parasites (sea lice)

Water Quality

Daily water sampling of  parameters  such as temperature, oxygen, and plankton  

  • All active sea cage sites
  • On-site sampling daily
  • Continuous remote sampling with sensors

Benthic Environment

Benthic assessments performed during peak feeding periods

  • As per Federal Aquaculture Activities Regulations (AAR)
  • Mandatory fallow periods
  • Re-stocking not permitted unless benthic environment meets regulations

Sea Cage Sites: Mitigation

Prevent Escapes

Certified, engineered cages and moorings

HDPE stainless steel core nets

Monthly underwater inspection reports submitted to regulators for review

Emergency plans, trained staff and equipment ready for deployment

Generational nets (reducing need for changes during production)

Minimize Interactions

(marine mammals, birds, fish)

Larger smolt to sea (reduce time at sea)

Siting in locations that minimizes overlap with wild salmon migration

Underwater cameras for feeding (to reduce excess feed in environment)

Vaccinating smolt against common bacteria & viruses

Transit speeds and observations to avoid whales

Bird netting over cages.

Debris containment on-site & routine beach/area cleanups

Manage Mortality

Healthy, robust smolt vaccinated prior to sea transfer

Aeration systems in cages (to circulate cooler oxygenated water from depth)

Deep nets (≥20 m) (to provide access to cooler water)

Stand-by vessels with capacity to collect in an emergency

Efficient mechanical and Remotely Operated Vehicle (ROV) removal of mortalities (faster removal than via SCUBA diver)

Managing Fish Health

Monitoring

Surveillance programs are on-going by many specialists and staff:

  • All fish certified disease-free before transfer to sea  
  • Daily observations of the fish by staff
  • Weekly sampling to check for sea lice
  • Monthly sampling for disease (Mowi)
  • Quarterly sampling for disease (FFA)

Reporting

Federal, Provincial and Mowi policies and procedures require reporting of sea lice as well as many diseases.

Mowi adheres to all reporting requirements 

Intervention

If prevention measures fail and the health of fish are a concern, under direction of Mowi veterinarian and consulting with Provincial veterinarian, intervention options include:

  • Therapeutants 
  • Mechanical removal of sea lice
  • Harvest fish

Transitioning to Sea

Moving from the hatchery to sea exposes smolt to various naturally-occuring bacteria, viruses, and parasites in the marine environment.​​

Sea lice are marine parasites. They attach to fish and feed on their mucus and blood causing wounds and sores.​​

Diseases are caused by bacteria and viruses. Administering vaccines before transfer reduces the likelihood of being infected. Also, screening parents (broodstock) aids to eliminate smolt that potentially could be infected because of genetics (vertical transmissions [parent to offspring]).