Mowi's Hellisay site offers exceptional water quality but pens have to be strong. Photo: Michael Macintyre / YouTube.

Mowi plans tougher, 200m pens after third escape from exposed site

Mowi Scotland is to seek permission to use 200-metre circumference pens at its Hellisay site, Barra after a third escape from the farm in the space of 27 months.

Published Last updated

The escape of 19,686 fish in February of this year led to Mowi being issued with an enforcement notice by government agency Marine Scotland.

Mowi now wants to use 200m pens – which would be the biggest in Scotland – because simulations show larger, high-specification high-density polyethylene pens perform better in big storm events, it said in the latest issue of its monthly newletter, The Scoop.

‘Most robust’ infrastructure

The first escape from Hellisay, which is Mowi’s most exposed site, occurred in November 2018 when the company lost 24,752 fish with an average weight of 1.1 kg. The second occurred in October 2019, when 23,970 fish with an average weight of 4.5 kg escaped due to what the company said was net failure.

In response to the three escapes, Mowi Scotland’s multidisciplinary team will deploy “the most robust infrastructure available to protect the health and safety of its employees and fish”, reported The Scoop.

Ben Hadfield: Enforcement notice "was fair given the incidents at the site". Photo: Mowi.

Good biology

Ben Hadfield, chief operating officer for farming in Scotland, Ireland and Faroes, told The Scoop: “We received an enforcement notice from Marine Scotland, which I thought was fair given the incidents at this site, and whilst we are pleased with the exceptional water quality and good biological performance of our fish in the Hellisay site, we are obviously disappointed with our containment record.

“Mowi has a clear target of zero fish escapes, and we are determined to meet this target even when challenged with extreme weather conditions. We also have a well-resourced and talented team, who are accomplished at solving such challenges.”

Experienced team

Investigations into past escape events have identified a failure in infrastructure (damage to pen structure and/or netting) during severe storms, reported The Scoop.

In response, Mowi has established a multidisciplinary team consisting of its most experienced farm managers from the Faroes, Ireland, Norway and Scotland and a range of consultancy services such as marine engineers and wave climate analysts to provide its recommendations on what is required to ensure the farm defends against a ‘one in 200 year’ storm event.

Mowi told Fish Farming Expert that it received an enforcement notice from Marine Scotland on March 15. The notice stated that it was “for the intent of ensuring that satisfactory measures are in place for the purposes of the containment of fish and the prevention of escape of fish” at Hellisay

Fit for purpose

The notice stipulated that “the equipment that is in use for holding aquaculture animals at that site must be repaired or replaced, suitable for the purpose and deployed in a manner that is appropriate for the environmental conditions predicted to be experienced at the site of deployment”. 

The solutions must include an “independent person of proven or demonstrable competence in relation to the design, installation and operation of aquaculture equipment”.

Mowi added that 200m pens are effectively used in Norway at similar rough weather sites.