Cermaq Canada recovering from algal bloom that caused 10 percent mortality

Cermaq Canada is recovering from a harmful algal bloom that impacted three of the company’s farms along the west coast of Vancouver Island in British Columbia, Canada.

The three farmare all located in the Tofino area of operations on Vancouver Island. A pair of harmful algae, chaetoceros concavicornis and chaetoceros convolutes, was detected at the two locations and has caused mortalities to salmon in the three farms.

“Three of our farms – Binns Island, Bawden Point, and Ross Pass ... are experiencing harmful algae blooms which are affecting our fish,” Managing Director for Cermaq Canada David Kiemele said at the start of the bloom. “These particular algae have rigid 'spines' that are harmful to fish when they come in contact with gills. Blooms are often associated with low dissolved oxygen events and warm ocean water temperatures and weather changes – all of which we are, or have been experiencing.”

According Cermaq, the losses have been limited and the bloom is largely cleared up now.

The Sea Shepherd Conservation Society, a environmental organization, took video footage and photographs of the three sites, which showed crew at the Cermaq farms cleaning up dead fish. The organization claimed that the losses were caused by viruses, and the company’s use of lice treatments due to “alarmingly high levels of sea-lice.”

Cermaq countered those claims, stating that the losses were entirely related to the algal bloom.

“We want to provide the most recent operational update to help clarify some of the unfortunate misinformation seen on social media. It looks as though a total of about 10 per cent of our population across the impacted sites will be lost. Mortalities are collected, stored and transported under strict biosecurity protocols, for use in rendering or fertilizer,” Kiemele said. “These recent mortalities are a result of the elevated harmful algae seen in the region, and not related to disease, our Hydrolicer operations or any other causes. The harmful algae embedded into the gills of our fish causing damage which unfortunately, can be fatal.”

Normally, the affects of a bloom can be somewhat mitigated by limiting activity at the farm, reducing feeding to keep fish at lower depths where algae is less present, and pumping water from deeper depths to dilute the algae in the system. However, the bloom was too concentrated to completely prevent mortalities, according to Kiemele.

“Our employees on all of our farms monitor water quality daily, this includes looking for multiple species of algae,” he said. “Unfortunately, given the concentration and species seen during this event, additional mitigation measures, post-identification, proved extremely challenging due to the species of algae identified and due to the fact that the algae was seen throughout the water column.”  

Image courtesy of Cermaq


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