Draft Seaweed Policy Statement Consultation Paper

Consultation paper on policy options for seaweed cultivation in Scotland

7 Commercial Seaweed Cultivation and IMTA

7.1 Current Situation

Commercial Cultivation

7.1.1 In 2010, the worldwide production of seaweed and other aquatic algae was around 19 million tonnes, of which 95% was cultivated [188] . World seaweed production is currently focused in the far east: 99.8% of global production by quantity and 99.5% by value in 2008. China accounted for 62.8% of this world production by quantity [189] . In Europe, seaweed production is comparatively small in scale, with production undertaken in France, Ireland, Norway, Portugal, the UK and Spain [190] . In both European and global terms, therefore, Scotland's role in seaweed production is small.

7.1.2 The potential for growth of the seaweed cultivation industry in Scotland has been identified by both public bodies ( e.g. The Crown Estate and Scottish Government) and industry, not just in incorporating seaweed cultivation into existing aquaculture operations ( IMTA), but potentially for larger-scale production in the future. However, Scotland's seaweed cultivation industry is still in its early stages.

7.1.3 At present, there are a number of seaweed sites, either in planning or operation, in Scottish waters. These sites are largely located in the Western Isles, Shetland or on Scotland's west coast. Marine licencing records indicate that these farms are being developed for algal production trials or as part of IMTA with either finfish or shellfish aquaculture (Figure 7.1).

7.1.4 Hatchery trials for the production of breeding stock and the cultivation of seaweeds have also been undertaken at a commercial hatchery in Argyll. These trials have been undertaken to determine the viability of laboratory culture of seaweed for transfer to marine cultivation sites [191] .

Figure 7.1: Finfish Farm, Shellfish Farm and Seaweed Cultivation Sites in Scotland (Source: Marine Scotland)

7.1.5 The potential for large offshore-scale production of seaweed is being investigated internationally, including work in recent years in the North Sea [192],[193] . Current efforts are focusing on the feasibility of such cultivation to support biofuel production.

Cultivation in IMTA

7.1.6 Scotland's finfish farming industry has the potential to increase organic matter and nutrient loading concentrations in coastal waters, as a result of the dispersal of waste feed and faeces from fish cages directly into the water column [194],[195] . In consequence, between 52 - 95% of the nitrogen, 85% of the phosphorus and 80 - 88% of the carbon input into a marine finfish farm can be lost to the marine environment. These losses occur as feed wastage, faeces production and respiration [196] , with a substantial portion of waste materials settling on the seabed below or near the cage. This increase in organic matter can impact on benthic ecosystems, and result in changes to the nature and chemistry of sediments, e.g. increased biochemical oxygen demand, with associated reductions in biodiversity [197] .

7.1.7 Nutrient enhancement of the water column can also be of concern, with these loadings, either suspended or dissolved, capable of being transported further afield. In Scotland, SEPA currently limits the biomass of farms, (and hence the amount of food and nutrients entering the water column) through licences whose limits are based on the results of modelling [198] . However, enhancement of nutrients has been identified up to 300m from farm cages in the direction of currents and flows in Scottish waters, and these nutrients can concentrate in quieter areas of flow [199] .

7.1.8 A potential solution to these problems is the use of IMTA, the multi-trophic form of integrated mariculture, which has been widely investigated both in Scotland and around the world [200] . As shown in Figure 7.2, the practice of IMTA combines the cultivation of fed aquaculture species ( e.g. finfish) with species that extract both organic and inorganic material ( e.g. shellfish/herbivorous fish and seaweed respectively) 'to create balanced systems for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptability (better management practices)' [201] . In this system, the nutrient waste from one species becomes the nutritional input for another.

7.1.9 The concept of IMTA is well-established in Asia [202] and is considered by the Fisheries and Aquaculture Organisation ( FAO) to be an important tool to achieve sustainable development. The effectiveness of coupling low trophic extractive suspension feeders ( i.e. shellfish and seaweed) to higher trophic fed ( i.e. finfish) organisms has been demonstrated for a wide range of species combinations in both fresh and marine waters [203] . Studies have also demonstrated the successful growth of a range of seaweed species ( e.g. P. palmata and L. saccharina) in the vicinity of finfish aquaculture cages in Scottish waters, and that significant increases in seaweed yield can be achieved from being in close proximity to these operations [204] .

7.1.10 The results of testing of IMTA on a small scale, using combinations of marine cage salmon farms, long line mussels, sea urchins and seaweeds in countries such as Canada, Scotland and Norway [205],[206] suggest a potentially promising future for the integration of seaweed cultivation and finfish aquaculture. With the exception of some companies cultivating sea urchins and seaweed alongside Atlantic Salmon in integrated systems, IMTA has had limited penetration into Scotland's mainstream salmon farming industry to date. This may change as the need to improve the productivity and sustainability of Scotland's aquaculture sites increases in the future [207] and as the benefits of IMTA are demonstrated to the industry.

Figure 7.2: Conceptual Diagram of an IMTA Operation using Fed Aquaculture and Extractive Aquaculture [208]

7.1.11 The scale and extent of any benefits will likely rely on design factors such as proximity of the seaweed and shellfish (where present) to the nutrient source ( i.e. the fish cages), and environmental factors such as local water conditions ( i.e. flows, shallow depth of the nutrient zone, etc.). The latter may limit the potential success of an IMTA system, for example, the light requirements of many seaweed species for photosynthesis may limit adoption of IMTA in deeper waters, and may introduce limitations in the species of seaweed that could be used for such sites.

7.2 Environmental Effects

7.2.1 The potential environmental effects of seaweed cultivation and IMTA are illustrated in Figures 7.3 and 7.4 respectively, and the likelihood and significance of these effects is discussed in the following paragraphs.

Figure 7.3: Potential Impacts for Commercial Cultivation of Seaweed

Figure 7.4: Potential Impacts for Seaweed Cultivation in IMTA

Creation of Refuges for Wild Stocks

7.2.2 As with wild seaweed communities, cultivated seaweed, either as a monoculture or in IMTA, may provide food resources and habitat for marine fauna such as wild fish (including juveniles), if only temporarily. This may have direct benefits for biodiversity and indirect benefits for local fishing interests.

Benefits in Managing Environmental Impacts from Aquaculture

The primary benefit of seaweed cultivation in IMTA is the potential alleviation of water quality and benthic habitat impacts from aquaculture, particularly finfish aquaculture (see Section 7.1). Similar benefits may occur in the event of co-location of seaweed cultivation sites in the vicinity of existing finfish farms.

Risks to aquatic fauna

7.2.3 Potential impacts on aquatic fauna include entanglement, obstacles to migration and by-catch during harvesting. The first, potential entanglement of fauna, would result from the presence of farm infrastructure such as lines and arrays and is of particular relevance to marine mammals ( e.g. cetaceans). The second relates to the creation of potential obstacles to marine species, particularly migratory cetaceans.

7.2.4 Migratory fish species include Atlantic salmon, sea trout, and lamprey and eel species. At present, there are significant data gaps in relation to the migratory routes of these species [209] .

7.2.5 Marine mammals are commonly sighted in Scottish waters and include both resident and migratory species. Marine mammals include:

  • Otters found all around the coast.
  • Seals (both harbour and grey seals) found in most of Scotland's coastal and inshore waters.
  • Small cetaceans (porpoises and dolphins) with a range of distributions [210] .
  • Migratory cetacean species ( e.g. minke whales).

7.2.6 At present, little is known about cetacean migration, including migration routes. Accordingly, large-scale cultivation sites, located either inshore or offshore in deeper waters, may be an obstacle to movement, but it is not clear how important this may be. Given that shellfish-scale and medium-scale farms will likely be located in similar areas to existing inshore aquaculture sites, their presence is unlikely to pose a significant obstacle to cetaceans or to migratory fish, due largely to their location in shallow waters. However, location of seaweed farms on migratory routes, where these are known, should be avoided. This will also be important for the siting of large-scale offshore sites in the future.

7.2.7 Cetaceans are known to become entangled in fishing gear, including nets, and minke whales in particular can become entangled in creel ropes [211] . We have not found any evidence of minke whales or other small cetaceans becoming entangled in aquaculture anti-predator nets and/or the ropes used for mussel farms. The same applies to seals. The risk of entanglement in seaweed cultivation ropes associated with shellfish-scale or IMTA inshore sites is therefore considered to be quite low. The risk may be different for larger sites, including those located further offshore, and this will need to be investigated further once more information is available on both migratory routes and the feasibility of such cultivation.

7.2.8 It is likely that seaweed cultivation sites will be colonised by other marine flora and fauna ( e.g. snails, shellfish, starfish, etc.). Some of these may attach to the cultivation ropes. At this stage it is not clear how cultivated seaweed will be harvested, since the method will likely depend on the species being farmed. In consequence, two broad methods of harvesting have been considered in this assessment: direct harvesting of the seaweed in situ, using methods similar to those used in harvesting wild seaweeds ( i.e. by hand or mechanical means), and ex-situ methods, involving the removal of the seaweed ropes by boat for harvesting. Harvesting may have adverse effects on colonising flora and fauna through the removal of seaweed habitat and/or the capture of non-target species when harvesting (known as by-catch).

7.2.9 Little information is available on current levels of by-catch associated with seaweed harvesting. It is considered likely that the majority of by-catch using both these methods would be limited to colonising flora and fauna and that these species will be relatively abundant in the marine environment. In consequence, we anticipate that these effects are unlikely to be significant at a national level for shellfish-scale, IMTA or medium-scale sites. However, the potential significance of impacts may be greater for large-scale offshore sites and this will need to be considered should such sites be progressed in the future.

Genetic Integrity/Displacement of Native Species

7.2.10 The cultivation of seaweed has the potential to affect seaweed species, and therefore wider ecosystem biodiversity, in the following ways:

  • Use of non-local spat could result in weakening of the genetic integrity of local seaweed species.
  • Use of non-local species could result in displacement of local seaweed species, with consequent effects on community structure and composition, e.g. through competition, displacement of wild seaweed stocks by cultivated species, etc.

7.2.11 The accidental or deliberate introduction of seaweeds has precedent both in Scotland and internationally. The accidental introduction and spread of S. muticum throughout Western Europe in the 1980s has had a range of negative effects, including impacts on the biodiversity of seaweed communities through outcompeting local species, and has also created navigation issues. Now regarded as a major nuisance species [212] , S. muticum is tolerant to environmental issues such as low levels of sunlight and variations in salinity and temperature, which enables it to occupy a broad range of habitats, including those with sparse algal development [213] . As such, it has become established in sheltered shores in low intertidal and shallow subtidal habitats in parts of Europe and off Scotland's west coast [214] , colonising predominantly highly disturbed habitats, but has also be found to invade saturated macroalgal communities [215] .

7.2.12 The introduction of pests and disease through cultivation activities has also been identified as a potential concern. Shipping and aquaculture have, in the past, contributed to the introduction and spread of non-native marine invasive species and disease [216] , and continue to present concerns today. However, unlike finfish, crustacean and mollusc culture, there is no evidence to show that seaweed diseases have been transferred as a result of seaweed culture [217] .

7.2.13 This is of particular concern, given the status of many seaweed species within the UK BAP, their identification within PMF, and their presence and contribution to European designated sites. The focus in the SPS on using local provenance and local species in cultivation was included to address these issues, and to preserve the genetic integrity of Scotland's seaweed communities by reducing the potential spread of non-native or translocated native species from cultivation activities to the wider ecosystem. This policy should also assist in limiting the opportunities for introduction of invasive non-native marine species and/or disease. This requirement is already being implemented through the marine licenses issued for seaweed cultivation in Scottish Waters (see Section 7.1). These do not identify the species of seaweeds that may be cultivated, but specify that only macro-algal species present in the local or regional area, and native to Scotland should be used in cultivation.

Ecosystem Biodiversity

7.2.14 Scotland's kelp forests provide important nursery and refuge grounds for fish [218] such as juvenile gadoids and salmon [219] , as do other seaweed communities, and it is likely that creation of seaweed farms would similarly attract marine fauna [220] . The removal of the 'created' habitat that a seaweed farm provides could have adverse impacts on the marine fauna that have come to rely on it, as harvesting would force these species elsewhere. The significance of this effect would depend on the species under cultivation. Some seaweeds can be harvested eight weeks after seeding, and a short growth period such as this is unlikely to provide significant habitat for other marine fauna. However, other (perennial) species are harvested annually, and this longer growth period may be of more benefit in providing habitat. In the latter case, the loss of habitat from harvesting would be a temporary effect, as the seaweed would begin to grow again.

7.2.15 Anecdotal evidence suggests that staged harvesting or 'crop rotation' of seaweed farms, as is undertaken for harvesting in the wild in Norway [221] and in Scotland [222] , may assist both in aiding seaweed regrowth and in mitigating disturbance of species residing in seaweed habitats, through extending the 'residence period' and, through staging, providing alternate refuge habitat. However, there are significant data gaps in relation to this issue.

Nutrient Supply

7.2.16 Seaweed cultivation relies on nutrients supplied naturally in seawater, and this has the potential to result in nutrient depletion in surrounding waters; such depletion has been observed in China. This may affect secondary productivity and thereby affect the wider ecosystem [223] . In addition, there may be increased competition for nutrients between seaweed farms in close proximity to one another, and between cultivated and wild seaweed stocks.

7.2.17 Nutrient capacity will therefore be a key issue for seaweed cultivation, as a consistent input of nutrients is required for growth. Studies in the far east have shown that it is possible to over-intensify seaweed farming, and that such over-production can result in nutrient decline. It has been suggested that this decline may be linked to outbreaks of disease in seaweeds, leading to reduced production. The carrying capacity of the local coastal environment should therefore be considered in seaweed cultivation proposals [224] .

Landscape and Cultural Heritage

7.2.18 Given the common equipment and similar scale of development proposed, it is likely that the visual impact of a shellfish-scale seaweed cultivation farm will be similar to that of current shellfish farms. Medium-scale developments are likely to be more visible, particularly those located near coastal areas, and as such, have the potential for greater landscape and seascape impacts. Extensive-scale developments may affect seascape as well as landscape along the coastline, and potentially the setting of coastal sites of historic importance. However, the significance of such impacts will depend on their extent, as well as their distance from the coast.

7.2.19 The potential for cumulative impacts from multiple marine or aquaculture developments is considered to be of primary concern, particularly in areas such as the west coast, Orkney, Shetland and the Western Isles. Such impacts depend on the nature and extent of the development and the sensitivity of the surrounding area. For example, the introduction of seaweed cultivation to an existing aquaculture site as part of IMTA may not significantly impact on landscape or seascape by itself, but may contribute to the impact of the existing developments, particularly if large in size and located some distance from the existing infrastructure. SNH has published guidance on the siting and design of aquaculture [225] to assist developers in integrating landscape and visual issues into the planning and design of aquaculture developments, and this will likely be helpful for seaweed farmers.

7.2.20 Given that the potential effects of seaweed cultivation on landscape, seascape and the setting of historic coastal sites will be site-specific, it is not considered that this issue requires to be addressed at the national policy level, for example in spatial terms. However, the Consultation Document notes that environmental considerations, such as visual and coastal impacts, must be taken into account in the planning, siting and design of seaweed farms (reflecting terrestrial and marine planning policy). Future spatial aquaculture plans will also include such considerations.

Benthic Issues

7.2.21 The potential effects of seaweed cultivation on benthic habitats and fauna include:

  • Benthic shading - due to presence of cultivated seaweed on ropes in the water column, which could potentially affect the composition of benthic communities through inhibiting the growth of photosynthetic organisms and affecting primary production in the water column [226] , or through decreasing the amount of light reaching species growing on the seabed ( e.g. eelgrass/sea grass [227] ).
  • Benthic smothering - for example, by fragments released from cultivation ropes, or by sediment trapped as a result of changes to hydrodynamic processes (see Section 5.4).
  • Nutrient enrichment by organic material ( e.g. fragments) released from cultivation ropes.
  • Habitat loss and/or damage from the installation of infrastructure ( e.g. placement of concrete anchoring structures) on the seabed.

7.2.22 The extent and scale of such impacts will depend on several factors, most notably the size of the cultivation development, the infrastructure required, and the sensitivity of the benthos in the vicinity of the proposed cultivation site.

7.2.23 While shellfish-scale cultivation may have local shading, smothering or nutrient enrichment effects, such effects are unlikely to be significant, particularly if appropriately sited. The main risk of such impacts is likely to be associated with large-scale cultivation, both inshore and offshore. There is little information available on this issue, but it is considered significant enough to warrant the inclusion of mitigation in the SPS, focusing on appropriate siting and design of cultivation sites.

Spatial and Siting Issues

7.2.24 There is the potential for conflict between seaweed cultivation and other marine users, largely associated with the potential for collisions and competition for space in the marine environment.

7.2.25 While the available information suggests that commercial activities result in relatively few marine accidents or fatalities (see Section 6.4), the potential for incidents ( i.e. collisions with vessels and/or site infrastructure) and safety concerns remain. Navigational issues are dealt with through marine licences and, in consequence, these issues will be managed at the project level. Seaweed farm developers will need to consider such navigational issues when planning and designing development, including the proximity of sites to known recreational areas and the potential for an increase in collision risk.

7.2.26 Shellfish-scale cultivation developments are likely to be located in Scotland's sheltered in-shore waters, for economic and proximity reasons. However, with increased competition for these areas, it is possible that future cultivation sites will be located further away from the coastline (depending on exposure levels). Accordingly, there is the potential for conflict with existing and future marine users in these areas ( e.g. shipping, renewables and recreational users), particularly for large-scale inshore and offshore sites, and the Consultation Document therefore includes a requirement that 'other marine users and activities should be considered in the siting of farms'.

Coastal Processes, Storm Protection and Water Quality

7.2.27 As noted in Section 5.4, seaweed can play an important role in coastal processes, by absorbing wave energy. Just as wild seaweed can alter wave patterns with associated impacts on coastal processes and exchange rates, the introduction of cultivated seaweed can also affect these processes [228],[229] . When a wave passes through a marine structure, it interacts with the structure in the same way as any other current, resulting in a loss of energy in the wave as this interaction occurs [230] . Such impacts will vary with the species under cultivation and the associated harvesting practices (as set out in paragraph 7.2.8). Seaweed at the shellfish-scale, with a short growing and harvesting period, is unlikely to affect coastal processes significantly. However, seaweed farms with longer growing times and annual (or longer) harvesting regimes have more potential for significant effects, particularly large-scale inshore and offshore farms.

7.2.28 These effects can include:

  • Increased sediment deposition in and around the seaweed farm, resulting from decreases in wave energy. This has the potential to alter local coastal processes over the long-term.
  • Improved storm protection by cultivating seaweed adjacent to coastal areas that are subject to storm and tidal surges. This could be of benefit for Scotland's vulnerable coastlines, including those identified as being subject to erosion, and those under increasing pressure from the effects of climate change.
  • Changes in water flows and nutrient dispersion. This may affect local biodiversity interests by slowing water flows and exchange rates, and changing nutrient supplies. In addition, a new seaweed farm can affect the viability of an existing one, for the same reasons.

7.2.29 The most significant effects are envisaged as arising from medium and extensive-scale cultivation and this will need to be investigated further as this becomes more feasible and the SPS is updated in the future. In the meantime, the Consultation Document notes that coastal processes may need to be considered in consenting medium-scale seaweed farms, particularly those located near to shore, depending on local conditions. It is also likely that the work currently underway on spatial planning of aquaculture will also include such considerations.

7.2.30 Where existing aquaculture equipment ( i.e. fish cages, shellfish ropes) is already present, this is likely to have reduced wave energy levels to a degree, and the addition of cultivated seaweed downstream of the nutrient source may further contribute to these impacts. In some instances, it may create additional effects if located some distance from the existing infrastructure. For new seaweed IMTA developments, the potential cumulative impacts of the system should be considered in the design stage

7.2.31 Benefits to local water quality may also occur due to seaweed taking up nitrogen from seawater, a well-documented benefit of macro-algae [231] . The role of seaweed in this regard may be beneficial for waters subject to high nutrient inputs, including marine and coastal areas near aquaculture sites, diffuse pollution or near waste outflows.

Storm Damage

7.2.32 Storm damage has been identified as an issue for finfish aquaculture ( e.g. in terms of equipment, escapes and introgression) and, in consequence, the industry has been working to agree a technical specification for equipment to withstand storm damage. Seaweed cultivation, including IMTA, will similarly need to be able to withstand storm damage.

7.2.33 As well as affecting equipment, storms can also affect the cultivated seaweed itself. For example, in calm conditions, seaweed fragments may be released into the water column and settle on the seabed and/or along coastlines. During storm conditions, however, large increases in driftweed volumes, potentially whole plants or groups of plants, may occur. These may be transported away from the cultivation site by the prevailing currents, and be washed up on the shoreline as cast weed.

7.2.34 This may have benefits (increased beach stabilisation, improved sand dune development) and could contribute to the creation of stable shoreline habitats, attracting a range of species that live and feed amongst the cast weed (see Section 5.4), whilst also increasing cast weed for 'gathering' by crofters (see Section 8.1). However, the decomposition of cast weed within two or three days of becoming washed up along the high tide line is often considered to reduce the aesthetic quality of the beach and can be seen as a nuisance, especially in areas of high tourist value [232] .

7.2.35 Derelict fishing gear, including nets, lines and floats amongst others, makes up around 9% of coastal marine litter in Scotland [233] . Accordingly, the Consultation Document identifies the need to ensure that equipment used in seaweed cultivation be 'fit for purpose' to prevent damage from adverse weather conditions, thereby reducing potential risks of farm equipment ( i.e. ropes, buoys, etc.) washing up in coastal areas or creating navigational hazards for other marine users or wildlife.


7.2.36 While seaweed cultivation and IMTA are in their infancy in Scotland, the potential for a number of significant impacts on the marine environment has been identified, particularly for Scotland's sensitive or vulnerable marine and coastal ecosystems. The nature of these impacts relates largely to the key role that Scotland's natural seaweeds play in these ecosystems and in coastal areas, and the national and international value attributed to the habitats that they service.

7.2.37 In general terms, shellfish-scale or IMTA cultivation is considered much less likely to result in significant environmental impacts than larger-scale development if appropriately sited and designed ( i.e. benthic impacts, collision risk, navigational issues), while offshore development may overcome many of the potential issues ( i.e. spatial siting, coastal impacts, etc.) identified for near-shore developments. Many of the potential impacts identified from the introduction of cultivation operations are likely to be site-specific, and as such, will be largely dependent on both design factors ( i.e. the scale of the development, infrastructure, etc.) and environmental factors ( i.e. location, water depth, the composition and resilience of the areas proposed for development). Importantly, the need to consider and assess environmental issues associated with future developments at the project level was identified.

7.2.38 The SPS is being developed to promote Marine Scotland's aspirations that growth in this industry is both sustainable and not at the expense of the wider marine environment. As such, it will likely contribute to overall positive environmental effects for biodiversity and water quality, particularly in relation to IMTA. In particular, the Scottish Government's support for the use of seaweeds of native provenance in cultivation to preserve genetic integrity of natural seaweeds, use of fit-for-purpose equipment and consideration of other marine users to address potential siting conflicts are likely to be the most relevant and beneficial in addressing the issues identified in this SEA.

7.2.39 However, it is noted that while the proposed SPS will encourage the sustainable development of seaweed cultivation and IMTA, and potentially create additional interest in the industry, the industry itself will play an important role in driving its future growth and managing the site selection process under the existing regulatory framework. As such, it is considered that the realisation of any benefits promoted by the SPS and this SEA, particularly those associated with IMTA, will be subject to the willingness of the aquaculture industry to drive these practices.

7.3 The Consultation Document and the Proposed SPS

7.3.1 The Consultation Document outlines Marine Scotland's support for shellfish-scale cultivation seaweeds, both as a single enterprise or as part of IMTA systems. This support is conditional, with the document detailing a series of policies stating that only seaweeds native to the area of cultivation should be cultivated, fit-for-purpose equipment should be used in cultivation operations to prevent damage in adverse weather conditions, and that consideration should be given to other marine users and marine activities in the siting of these operations. It also states that where seaweed is grown for human consumption, cultivators should site farms away from sewage outfalls and other potential sources of pollution.

7.3.2 Marine finfish aquaculture is spatially limited to the west coast of Scotland, the Western Isles, Shetland and Orkney and, in consequence, the cultivation of seaweed in IMTA will be similarly limited. The Consultation Document details no other spatial limitations.

It also sets out Marine Scotland's view that applications for medium-scale seaweed farms ( i.e. 41 to 80 x 200m lines of seaweed) should demonstrate that mitigation measures have been considered to prevent adverse environmental impacts. While the Consultation Document does not detail a policy position on extensive-scale developments ( i.e. for use in biofuel production) as this sector is currently in the research and investigation stage of development, it is intended that should this sector progress and develop in the future, the development of policy will be revisited at that time.

7.4 Mitigation

7.4.1 The environmental issues identified by the SEA are such that very few issues need to be addressed at the national level. The SEA found that many such impacts and benefits were likely to be site and activity specific, and would benefit from being addressed at the regional or project level.

7.4.2 Issues that do require treatment in the proposed SPS were considered to include the preservation of genetic integrity, conflicts with other marine users, and risks associated with storm damage. The Consultation Document has been developed to identify and mitigate potential environmental issues. As such, the broad policies outlined in the Document have been progressively developed alongside the SEA to address these issues at the national level, whilst promoting their consideration in future applications for seaweed cultivation and IMTA.

7.4.3 Issues to be addressed at the regional and project level include risks to aquatic fauna, coastal processes, benthic issues, water quality and ecosystem and shoreline biodiversity, and visual issues. Activity-specific factors such as the size and scale of cultivation operations, the proximity to other marine activities or to sensitive marine areas, the type of species cultivated, and harvesting techniques are also likely to have an influence on these issues. Site-specific and environmental factors such as wave patterns, coastal processes, ecosystem composition and species sensitivity will also likely exert influence over the occurrence and extent of impacts from seaweed cultivation operations.

7.4.4 Individual projects will need to be progressed to planning and consenting in light of the policies contained in the draft NMP, future Regional Marine Plans, and in local development plans and/or supplementary guidance relating to aquaculture. Siting and design work at the project level will wish to front-load these considerations.


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