Mowi wants to add an extra 160m pen like this to its Maol Ban site. The change will bring several benefits including reduced crowding timescales.

Mowi seeks more room for fish at Sconser

Extra pen will enhance salmon health and welfare, planners told


Mowi Scotland is planning to boost fish health and welfare by giving salmon in its Maol Ban farm off Sconser in Skye more room by adding an extra pen.

Mowi has applied for planning permission to add a sixth 160-metre circumference pen at the site, which would fit neatly into a gap in the existing grid. The site’s maximum stocking biomass of 2,250 tonnes will remain the same, as will maximum production biomass per cycle of 3,283 tonnes, but stocking density will be reduced from 14.7 kg per cubic metre to 12.3 kg/m³.

Among other fish welfare benefits, the company said crowding timescales for treatment/harvest operations would be reduced significantly.

Continued improvement

“Maol Ban has successfully operated 160m pens since permission was granted in 2021,” wrote Mowi Scotland environmental analyst Connie Fairbairn in a submission to Highland Council planners.

A plan showing how the new pen (in red) would fit into the existing grid.

“This proposal for one additional 160m pen will continue to improve the efficacy of existing operations, as no change to existing consented biomass is sought. An overall reduction in stocking density across the site of >2 kg/m³ will allow for greater efficiency in sea lice control while supporting fish health and welfare, with crowding timescales for treatment/harvest operations intended to reduce significantly on a pen-by-pen basis.

“The potential for lice and disease transmission between fish will also be reduced through the introduction of an additional pen, while simultaneously aiding gill health through improved proximate water quality and reduced oxygen demand.”

Obligation to environment

Fairbairn added that Mowi considers its obligation to environmental standards and regulatory thresholds to be of the highest priority, and that there is considered to be no likely significant effect to the water column or benthic environment from the extra pen, as the site will maintain the current biomass.

“There will be no change to existing sea lice controls or health management practices through the installation of an additional pen, licensed medicine quantities will also remain the same.”

In line with Mowi Scotland’s policy that all of its ‘conventional’ and ‘high energy’ location farms should have nets constructed from HDPE SealPro or equivalent standard by the end of this year, the net used will be comprised of 18 mm knotted HDPE braid with HDPE fibre core.