Environmental Assessment (Scotland) Act 2005 Aquaculture and Fisheries Bill Consultation Document Environmental Report February 2012

This Environmental Report sets out the results of the assessment of the possible environmental effects of provisions in the Aquaculture and Fisheries Bill.


Current Situation

10.1 Operators have a responsibility under the Aquaculture and Fisheries (Scotland) Act 2007 [47] to take satisfactory measures for the control, prevention and reduction of sea-lice and to safeguard the health and wellbeing of the fish in their care. Operators must demonstrate that satisfactory measures are in place to control sea-lice levels through maintenance of records on management area operations.

10.2 The management of sea-lice is a complex issue and typically involves the implementation of a range of measures to control sea-lice levels in farmed fish populations. Management measures may include single year class production, farm area management, synchronisation of production across farm areas, fallowing at the end of the production cycle, and the more recent use of "cleaner fish" such as wrasse [48] . These measures are typically undertaken in combination with the regular use of therapeutant. Treatments may be applied in three ways: in-feed, in-bath or using wellboats.

10.3 The frequency of therapeutant applications on an individual farm and on farms in a given FMA can vary. Treatment frequencies are dependent on the stage of fish development, time of year, location of the farm and the levels of lice observed during monitoring.

10.4 The actual performance and effectiveness of treatments is a subject of concern. The WWF working group report observed that, in recent years, the industry has become increasingly reliant on a few available licensed treatments for sea-lice and that there are concerns about resistance to treatment emerging in sub-populations of lice [49] . The ICES Working Group highlighted similar concerns in Norway [50] .

10.5 The CoGP sets out the approach to managing sea-lice, including (at Annex 11) the National Strategy for Sea-Lice Control. This includes non-therapeutic management and sea-lice treatments, on a co-ordinated basis, with an objective to prevent the development of gravid females. If this strategic approach to 'prophylactic' treatments is effective, there is a reduced risk of infection of wild salmonids from fish farms.

10.6 The CoGP currently suggests the following criteria as thresholds for sea-lice treatment:

  • During the period 1 st February to 30 th June inclusive, the criterion for treatment is an average of 0.5 adult female L. salmonis per fish.
  • During the period 1 st July to 31 st January inclusive, the criterion for treatment is an average of 1.0 adult female L. salmonis per fish.


10.7 The proposed provisions include additional powers to Scottish Ministers to determine a lower threshold above which remedial action needs to be taken, including at certain times of year, in key areas of Scotland with significant wild fisheries, and/or where fish farming involves high biomasses of fish (meaning the overall burden of lice may be significant). This would be subject to consultation with appropriate local interests in the areas concerned.

Potential Effects

10.8 While the CoGP details sea-lice management regimes and treatment triggers, in some circumstances this management regime may be insufficient to assist in the management of risks of outbreaks in farmed stocks and wild salmonids in that area. The proposals have the potential for significant benefits to wild salmonid populations.


10.9 As no significant negative effects from these provisions have been identified, no mitigation measures are required. Given the high-level nature of the provisions, enhancement measures have not been proposed at this stage of the Bill's development.

Effects of Continuing the Status Quo

10.10 Continuing the current situation would result in the continuing risk that sea-lice outbreaks could occur, in certain times of year in key areas of Scotland with significant wild fisheries, that would have adverse implications for wild salmonid populations.


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