Draft Seaweed Policy Statement Consultation Paper

Consultation paper on policy options for seaweed cultivation in Scotland

Section 1: Draft Seaweed Policy Statement (SPS)

This section sets out the draft SPS. It describes and seeks your views on Scottish Government policy on:

  • Stand-alone commercial seaweed cultivation; and
  • Commercial seaweed cultivation within Integrated Multi Trophic Aquaculture ( IMTA) systems.

Given the issues considered in the SEA Environmental Report and the potential impacts identified, we have developed a number of draft policies that will directly inform licensing decisions and should be considered by developers in advance of submitting license applications. Where relevant, these are listed under each section.

Commercial seaweed cultivation

Different species of seaweed have differing habitat requirements, but all require good water flow to provide nutrients. The west coast of Scotland offers suitable inlets and sea lochs for seaweed cultivation, with many of these already being used for aquaculture production. However, there may also be potential for seaweed growing in areas other than the west coast.

Commercial seaweed cultivation is considered to have the potential to take place at a number of different production scales. For the purpose of the SPS we have considered three distinct scales: 1) shellfish (small), 2) medium, and 3) extensive.

Seaweed cultivation may result in either positive or negative impacts on the marine environment and other users of marine waters. Table 4.1 of the SEA Environmental Report details the potential effects of seaweed cultivation on the landscape and seascape, climate, biodiversity, human health, water quality and the marine environment, marine geology, air quality, cultural heritage, and marine assets.

Whilst there is currently a lack of evidence to suggest that releases of sewage and other effluent pose a risk to human consumers of farmed or wild harvested seaweed, those involved in growing or collecting seaweed should be aware that a contamination risk may exist, depending on current flow characteristics, historic discharges and accumulation in the environment ( i.e. for heavy metals). As such, the seaweed sector could locate in designated shellfish waters, where water quality is already protected for harvesting products for human consumption.

However, the Scottish Government does not intend to use the presence of seaweed production as a sole justification or driver for improvements to water quality or to impose additional requirements on operators of authorised activities making discharges to the water environment.

Shellfish (small) scale

Shellfish scale (0-40 x 200m lines) refers to lines that are used to grow seaweed and that are a similar size to a typical mussel farm. The map below shows the current seaweed sites on the west coast of Scotland and around Shetland that would be termed shellfish scale sites. Anecdotal evidence suggests this sector may grow significantly in the short-to-medium term. The SEA Environmental Report indicates that there is likely to be limited environmental impact from sites of this scale.

Shellfish (small) scale

The policies relevant to shellfish scale seaweed cultivation are:

  • Policy 1 - In principle, the Scottish Government is supportive of shellfish scale seaweed cultivation, subject to regulatory consideration.
  • Policy 2 - Only species native to the area where the seaweed cultivation will take place should be cultivated, to minimise the risk from non-native species.
  • Policy 3 - Where seaweed is grown for human consumption, cultivators could site farms away from sewage outfalls and other potential sources of pollution.
  • Policy 4 - Equipment used in seaweed cultivation should be fit for purpose to prevent damage from adverse weather conditions.
  • Policy 5 - Other marine users and activities should be considered in the siting of farms.
  • Policy 6 - Shellfish scale farming is not spatially limited, and may be located anywhere in Scotland with appropriate local conditions and with due regard to the marine environment.

Medium scale

Medium scale refers to sites exceeding the size of a typical mussel farm (41-80 x 200m lines), but smaller than extensive scale.

The SEA Environmental Report indicates that there may be potential negative environmental impacts from sites of this scale, primarily in relation to benthic shading but also in relation to visual impacts, collision risks, spatial issues, and coastal impacts.

Policies 2, 3, 4, 5 and 6 are also relevant to medium scale seaweed cultivation.

  • Policy 7 - In principle, the Scottish Government is also supportive of medium scale development, subject to regulatory consideration. Applications for such seaweed farms should demonstrate that mitigation measures have been considered to prevent adverse environmental impacts, and set out how these will be delivered.

Integrated Multi Trophic Aquaculture ( IMTA)

The Scottish Government is supportive of IMTA, the term given to the co-culture of species for environmental and economic benefit.

In IMTA systems, species which are fed or farmed (for example Atlantic salmon) are grown alongside species whose culture results in nutrient (or energy) extraction (for example sea urchins, mussels or seaweeds). The aims are for greater efficiency in resource use such as feedstuffs, space, and labour, with a consequent reduction in negative environmental impacts.

Seaweed grown in such systems will therefore be co-located in areas of aquaculture production.

Operators should be aware that equipment for the entire operation should be fit for purpose and that any unsecured equipment from shellfish or seaweed operations could compromise the integrity of the forthcoming Scottish Technical Standard.

Policies 2, 3, 4, and 5 are also relevant to IMTA.

  • Policy 8 - The Scottish Government is supportive of IMTA.
  • Policy 9 - Where seaweed is grown in IMTAs alongside finfish, it is spatially limited to the West Coast of Scotland, the Western Isles, Shetland and Orkney. This is due to the continued presumption against further marine finfish developments on the north and east coasts, as detailed in the Scottish Planning Policy document and the forthcoming National Marine Plan.

Extensive scale

Extensive scale refers to sites that are larger in size that may utilise different equipment to that used in shellfish production. Such sites would have the potential for development for biofuel production, but as the industry is very much in its infancy, there is currently no consensus over the size or viability of such sites. This will only be identified as seaweed farms for biofuel production and other co-products are proposed in the future.

Seaweeds have a high sugar and carbohydrate content which, through fermentation and bio-refining can produce bioethanol or biobutanol, a high energy fuel which burns in the same way as petrol. The attraction of marine origin biofuels over those of terrestrial origin is that the former do not impact on limited land and freshwater resources that could be used for food production.

As hundreds of thousands of hectares of seaweed are likely to be required to be cultivated for biofuel production, this industry is currently limited by technical feasibility and economic and environmental considerations. For this reason, these types of development have not been considered in the SEA Environmental Report and the SPS contains no policies for this scale. If the sector looks likely to develop, the report and policies will be revisited at that time.


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