Scottish Government

3 Existing Baseline Status

This section aims to describe the existing context within which the plan operates, and the constraints and targets that this imposes on the plan.

The SEA is being undertaken on the programme principles and process and cannot examine the implications at specific sites. The baseline data is therefore restricted in scope, and only general national or regional information can usefully be referred to. More detailed baseline assessments will occur at EIA level.

3.1 Industry

The Scottish aquaculture industry has grown rapidly since the 1970s and early 1980s. In 2005 there were 69 fish farming companies (57 in active production) ⁷. Annual production in 2004 was 159,000 tonnes but is expected to have fallen to 136,000 tonnes in 2005 as a result of company closures, consolidations and storm damage.

Figure 2

The industry currently provides direct or indirect employment for some 8,500 people, many of them located in remote and fragile coastal and rural communities. It contributes 50% of Scotland's food exports by value and generates around £300m pa in farm gate sales and £800m pa retail.

Figure 3

There are currently 224 active sites but 235 inactive sites and just 55% of the available consented biomass for production in Scotland is currently being actively used (186,000t). Some of the spare available capacity may be unsuitable for development in present circumstances - for example small or poorly located units.

Figure 4

It is recognised that the planning application and consents procedure has become stricter over time and earlier leases were considered prior to the large body of relevant scientific work now available. As a result earlier applications were subject to a different assessment, referring to a different level of evidence. It is conceivable that some existing farms would not now receive a lease for their current location but these farms are subject to continued assessment by SEPA who are able to control impacts on water quality through the Controlled Activities Regulations.

3.2 Environment

The Coastline of West Scotland and the Western and Northern Isles are important for their scenic beauty and biodiversity, and this attracts large numbers of tourists. Equally the coastal and marine environment is an important resource directly supporting a range of economic activities. These are potentially competing needs which can be assessed and agreed within existing planning and regulatory frameworks.

Scotland provides a globally important habitat for wild salmonid species. While there is as yet no definitive assessment, on the basis of our current understanding it is estimated that there are likely to be several thousand distinct genetic populations of salmon inhabiting some 380 rivers. The potential for interaction between wild salmonids and farmed populations is one of the main drivers for this programme. The majority of the species diversity and abundance resides in East Coast rivers, where there is a presumption against aquaculture development. However on the West Coast there are some 300 salmon rivers providing habitat for hundreds of genetically distinct populations. Although the West Coast rivers and salmonid populations within them are typically small there is an important diversity of genetic phenotypes.

Figure 5

Data also shows that both salmon and seatrout catches have declined substantially since the 1960's (Figure 5). The reasons remain unclear though many possible factors have been suggested including changes in water temperature, food supply, fishing pressure, impact of seals, disease, barriers to migration and factors associated with fish farming, including increased sea louse infection. However, this decline has taken place in all areas, including those without fish farms.

The biodiversity and scenic value of Scottish West coast and islands are recognised in a number of designations. The target of these designations and the scale of protection that they afford differ. The diverse shores and coastal waters of Scotland include a number of the marine habitats and species listed in Annexes I and II of the Habitats Directive. The best areas for these habitats and species, within inshore waters and out to the limit of UK territorial seas, have been proposed as candidate Special Areas of Conservation ( SACs). As at 1 April 2005, a total of 34 sites with marine interest have been designated as SACs. None of these are designated in respect of Atlantic Salmon but several rivers on the west coast have been, for example Langavat on Lewis and the Gruinard River.

In addition the Fisheries Research Service has identified 15 river systems which they consider to be priority in respect of conservation of wild salmon and sea trout.

There are a number of data sources and indicators to provide a baseline of environmental condition of the Scottish Coast. Many of these are of particular relevance to environmental factors thought to be of significance to aquaculture. These are appended to this report as an annex.

3.3 Interactions and Impacts of Aquaculture

In scoping for this report it was agreed by all statutory consultees that this programme must consider interactions with ⁸:

• Biodiversity, flora, fauna
• Human Health, Population
• Water, air & climatic factors
• Material assets, cultural heritage, landscape
• Interrelationships of these.

These categories are broad and non-specific, whereas the potential impacts of aquaculture are often focussed on specific areas of concern, subject to a large body of detailed scientific research. There is also a good body of synthesis and summary work reviewing current state of overall knowledge.

A detailed review of these interactions was carried out as background to the development of the strategic framework ⁹. More recently FRS has undertaken a review of sea lice infections and proximity of farms to river estuaries ¹⁰. The following represents a brief up-to-date summary.

3.3.1 Wildlife Interactions

There are a number of ways in which fish farms interact with other marine fauna.

The main driver of the Location / Relocation Working Group has been the interaction on wild migratory salmonids via:

• Sea lice infestation (due to proximity)
• Other diseases (due to proximity)
• Genetic interaction (in event of escapees)
• Direct competition (in event of escapees)

Wild salmon and sea trout are most at risk from infective larval sea lice in long fjordic systems where farms lie adjacent to migratory routes ¹¹ - a problem exacerbated in poorly flushed lochs. The exact scale of the problem and the nature of the dynamic relationship between lice in wild and farmed populations is unclear. It has however been illustrated through sub-littoral plankton surveys that there are higher concentrations of lice around some farms ¹². This would constitute an increased louse infection pressure on wild salmonids in the vicinity of such farms ¹³. It has been suggested that this pressure is at least partly responsible for the decline in wild salmonid populations. Unfortunately the science is at times contradictory, the links between farmed and wild salmon infection are complex, and the overall impacts on the health and viability of wild populations very difficult to determine. Furthermore, this is a two way problem, with the possibility of wild populations acting as a reservoir for lice during farm fallowing periods ¹⁴. The environmental review referred to above comments that:

"Although the relationship between sealice infection and the decline of wild populations is striking, and is additional to the widespread decline of migratory salmonids in areas without fish farms, there is as yet no absolute proof of causal link. In spite of this, and owing to the increasing body of supporting (although as yet inconclusive) evidence, the burden of opinion has recently begun to swing in favour of accepting the likelihood that lice from farms constitute a direct threat to wild salmonids".

More recently, Cunningham draws the following overall conclusions:

• Severe lice infection causes physiological disturbance and physical harm to salmon and sea trout. Smolting fish appear more susceptible to damage than post-smolts
• Sea lice prevalence of over 95% is usual in areas without salmon farms, but varies seasonally
• Farms with high numbers of sea lice increase the louse infection pressure in the vicinity; nevertheless the relationship between numbers of lice on the farm and numbers of infective larvae in the surrounding area is not straightforward.
• Although there is no conclusive proof that heavy lice burdens and premature return of trout smolts is a causal factor in the decline of wild populations, where control measures are feasible, steps should be taken to reduce the incidence of infective lice larvae in areas where wild salmon and sea trout smolts enter seawater.

Although many in the salmon farming industry do not accept that the sea lice problem is a significant factor in the decline of wild fish populations, it is now widely agreed that moving salmon farms away from areas important for wild salmon and sea trout is desirable, and in conformity with "the precautionary approach", especially since further scientific study is unlikely to resolve the debate, at least in the short-medium term. These conclusions effectively serve as the main rationale and driver for the relocation programme, although other environmental interactions must also be taken into account.

Some recently completed research ¹⁵ of particular relevance to this programme suggests that sea lice are much less infectious in low salinity water, and that the main risk therefore relates to salmon and sea trout outside the immediate influence of the river mouth.

The transfer of other parasites and pathogens from farmed to wild fish is not thought to be a major problem at present - although difficulties in measuring prevalence, incidence, and pathogenicity of diseases in wild populations complicate understanding of implications of disease ¹⁶. The greatest disease risk to both farmed and wild salmonids comes from the introduction of exotic pathogens into areas where local stocks have no resistance. This has occurred in the past ¹⁷ but is now safeguarded against by national and international legislative controls, supported by improved farmed practice. The threat is therefore greatly diminished and the anglers and farmers are united in determination to prevent further infestations - in particular of Gyrodactylus salaris¹⁸.

Escapes of farmed-reared salmon into the wild may pose a threat to local salmonid populations due to out-competing within a small ecological niche, interbreeding and in some cases disease transfer. Certainly, there is some evidence that when sexually mature farmed salmon escape they enter fresh water and spawn ¹⁹. Mortality in the progeny of escaped farmed salmon is higher than wild counterparts but those that do survive grow faster ²⁰. The introduction of non-adaptive genes and increased homogeneity that can occur as a result of interbreeding may lead to loss of naturally selected adaptations and reduced fitness or performance.

The interactions of aquaculture and wild salmonid populations also have implications for the freshwater pearl mussel Margaritifera margaritifera the larvae of which attach to the gills of migratory salmonids.

There are further interactions between fish farms and wildlife, in particular with sea birds, mammals and cetaceans. The most significant interaction is with seals and it is in the companies' interest to locate away from seal haul out areas. Where predation by seals is a problem acoustic deterrent devices ( ADDs) are used. The high frequency sounds which are emitted by ADDs are designed to exclude seals from the immediate area. Their use, and occasional permitted shooting of seals, is likely to come under scrutiny in areas (or close to such areas) proposed for SAC status for seals or in areas where cetaceans occur due to their increased sensitivity to high pitched acoustic noise.

3.3.2 Wider Environmental Interactions

There is no reason to believe that relocation of aquaculture will have any significant effects on air quality or climatic issues, or on human health, and they are not considered further in this report.

There are however interactions between fish farms and the wider marine (or freshwater) environment which must be taken into account when reviewing the environmental impacts of a range of policy decisions. These include:

• Localised organic enrichment
• Local water quality - chemicals
• Cumulative impacts on water quality (environmental capacity)
• Biodiversity and Water Framework Directive ( WFD) "Good ecological status"

The most obvious and apparent of these is organic enrichment of the benthic environment in the vicinity of the cages. The scale of this impact is closely monitored (and modelled) by SEPA and although particulate organic waste from cage farms has a profound effect on the benthic environment, severe effects are confined to an extremely localised area (few hundred metres at most). This is recognised by the acceptance of the Allowable Zone of Effect approach ( AZE) applied by SEPA. Partial recovery after cessation of farming is rapid and total recovery occurs within two to three years. By area, fish farms occupy a tiny area of the Scottish coast and it is unlikely that organic wastes on the seabed will be the environmental factor limiting increases in production ²¹.

Local water quality is also impacted by release of nutrients from waste products and potentially from the use of medicines. Again this is closely monitored by SEPA and medicine licensing restricts the use of certain toxins, many of which are available for use in other major aquaculture nations.

The use of automated feeding feedback loops (infra-red, doppler, cameras, pumps) has greatly increased understanding of feeding patterns and has contributed to more efficient feeding with reduced waste. This has undoubtedly led to a reduction in localised organic enrichment, both on the seabed and in surrounding waters. Improvements in diet digestibility have also improved local water quality.

The greatest determinant of water quality remains flushing rate. There is often a strong correlation between poor flushing rate, organic enrichment and sea lice burden. As such proposals to relocate farms to better flushed farms are likely to reduce lice burden with the additional benefit of improving localised water quality.

SEPA ' Depomod' tool is now used in support of site consent applications. This models local hydrodynamics and dispersion. SEPA now favour highly dispersive sites and new sites are less likely to be in areas where localised organic enrichment is a danger.

This modelling tool does not yet consider wider impacts of cumulative loading and in particular how this relates to overall Environmental Capacity - the inherent property of the environment to assimilate or process waste from natural or anthropogenic activities. Understanding this enables assessment of Carrying capacity - the amount of a given activity that can be accommodated. Sustainable aquaculture depends upon nutrient and chemical inputs remaining within the environmental capacity of the surrounding aquatic environment.

Environmental quality standards ( EQS) have been established to ensure that concentrations remain well below the level at which adverse ecological effects are detectable ²². Advice on these standards and the carrying capacities of marine locations can be obtained from SEPA, FRS and Dunstaffnage Marine Laboratory. In practice carrying capacity is highly dependent on water depth and water movement, and these in turn may be associated with exposure.

3.3.3 Socio economic Interactions

Although strictly not part of an environmental assessment it is vital that strategic programmes of any kind take into account social and economic as well as the environmental effects. This is particularly the case given the many current initiatives relating to marine management (see annex 7.3) and the overriding commitment to sustainable development in Scotland's marine strategy ²³. The Food and Agriculture Organisation of the United Nations even recommends that social impact assessments ( SIAs) are undertaken at the same time as environmental impact statements ( EIS) ²⁴.

Aquaculture provides employment in remote areas where chances of alternative employment may be limited, thus improving the prospects of the community remaining as an economically active part of society ²⁵. Most independent assessments of the social impacts of fish farm development have been positive ²⁶²⁷.

However social and economic assessment must also consider interactions with other users, cultural heritage, landscape and tourism. This is especially important given the high number of cases where applications for siting fish farms are turned down because of concerns raised about these issues ²⁸.