E Detailed Assessment Methods for each Sector
Detailed methods for assessment of negative economic impacts for each sector, for those interactions that have been scoped in (see Appendix D), are presented in the sections below.
Cable routes are not yet known. A qualitative assessment of the impact of export cables is carried out where feasible, taking into account potential constraints inshore of the DPOs.
The DPO overlap with various Helicopter Main Routes on the east coast, east of Shetland, and with the Aberdeen-Atlantic Rim Helicopter Main Route off the north coast. There is a need for further assessment of:
- Height obstruction to commercial helicopter navigation routes from arrays.
Method for assessment of height obstruction of commercial helicopter navigation routes from arrays (construction and operation): the potential social and economic impacts will be determined in consultation with helicopter service providers. This will take into account additional track miles for helicopters owing to height obstruction in inclement weather, resulting in additional costs.
Data limitations: Helicopter Main Routes (HMRs) represent the routes typically flown by helicopters operating to and from offshore destinations and are ‘signposts’ to aid flight safety (i.e. signposting concentrations of helicopter traffic to other air space users). Whilst HMRs have no airspace status and assume the background airspace classification within which they lie, they are used by the Air Navigation Service Provider (ANSP) (i.e. NATS Aberdeen) and helicopter operators for flight planning and management purposes. While compliance with the HMR structure is not compulsory, in the interests of flight safety, civil helicopter pilots are strongly encouraged to plan their flights using HMRs wherever possible. The HMRs do not predict the flow of helicopter traffic.
E.3 Carbon Capture and Storage
The Mains and Captain saline aquifers overlap with one or more of the DPO. There is a need for further assessment of:
- Competition for space (arrays and cables).
Method for assessment of competition for space (sterilisation of the seabed in relation to potential storage areas, and obstruction of potential pipeline routes): further consideration will be given to the potential socio-economic impacts in consultation with the Carbon Capture & Storage Association (CCSA). For sterilisation of seabed, the development potential of the saline aquifers will be assessed, based on studies such as ACT Acorn (2008), and additional data on the spatial extent of the saline aquifers and planned location of development. In relation to obstruction of potential pipeline routes, the potential for existing pipelines to be used for transport of CO2, will be assessed, and any potential new pipeline routes will be considered in relation to overlap with DPO areas.
Data limitations: There are no commercial-scale CCS projects in the UK and uncertainty remains regarding the economic viability and the future location and scale of CCS activity in the UK.
E.4 Energy Generation
There are spatial overlaps between the DPOs and wave and tidal draft plan option areas. There is a need for further assessment of:
- Competition for space from arrays.
Method for assessment of competition for space: It is currently unclear whether or when wave technologies might become commercially viable. Wave resources are widely distributed in Scottish waters and the use of some potential wave resource areas for offshore wind development is unlikely to compromise development of a wave energy sector in Scotland. The detailed assessment will take account of the spatial extent of overlap between the offshore wind DPOs and potential wave development areas and consider the potential social and economic impacts in consultation with Scottish Renewables.
Data limitations: Offshore wave energy is not yet a well-established industry and therefore it is difficult to determine the interactions with offshore wind and the degree to which any spatial overlap will affect energy generation. The future of transmission capacity will depend on the location of future energy generation and levels of investment in grid infrastructure.
E.5 Fisheries (Commercial)
There are spatial overlaps between the DPO and existing fishing grounds. Loss of existing fishing grounds can lead to a displacement of fishing activity, with other knock-on consequences, and/or a loss in the value of landings affected should the affected fishing activity cease. This can have further impacts on output and GVA of the sector, and impacts on processors. There is a need for further assessment of:
- Complete loss or restricted access to traditional fishing grounds (arrays and cables);
- Changes in fishing patterns, including gears used and species targeted (arising from displacement of fishing vessels as a result of loss of traditional fishing grounds) (arrays and cables);
- Obstruction of fishing vessel navigation routes (arrays and cables);
- Fouling of fishing gear on cables or seabed infrastructure (cables – operation);
- Consequential impacts to seafood processors.
Method for assessment of complete loss or restricted access to traditional fishing grounds (arrays and cables): Potential negative impacts on commercial fisheries may occur principally through the loss of (or displacement from) traditional fishing grounds due to the location of arrays. The loss of fishing grounds could lead to a reduction in catches/landings and income for affected vessels. The value of landings affected by the DPOs is assessed for individual fleet sectors (over-12 m and under-12 m and by gear type for gear types that will not be able to operate within the arrays) as follows:
- Average annual value of landings by UK vessels from the DPO area, pro-rated by the proportion of the DPO area that would be occupied by the array under the different development scenarios (based on the ‘Realistic maximum development scenario for the DPO’ as a proportion of the ‘Potential installed capacity’ of the DPO, see Table 2). For vessels over 12 m in length, this is assessed using VMS data linked to landings declarations for pelagic, demersal and shellfish species groups (annual average value over 2013-2017). For vessels 12 m and under, Scotmap data (value of all gears layer) is used to calculate the proportion of fishing activity per ICES rectangle that is within each DPO area. These proportions are applied to the value of landings from each ICES rectangle (annual average, 2013-2017, for demersal, pelagic and shellfish species groups). A static baseline is used, assuming the same value of landings in each year of the assessment period.
- The potential impact on non-UK vessels is assessed based on VMS pings (not linked to landings data) to identify the nationalities of vessels that may be affected.
We assume a worst-case scenario that all landings from a DPO area are lost, and displacement of fishing activity to other areas does not occur. In reality, some displacement is likely, which would result in additional landings from other fishing grounds and a lower impact on the commercial fishing sector. However, there would be additional impacts associated with this displacement of activity, including longer steaming times, changes to vessel cost/revenue profiles, changes to catch per unit effort, impacts on habitats and species in the areas to which vessels are displaced to, and potential conflict between gears and different fishing segments in the areas to which fishing is displaced.
Where there is a reduction in landings value, the impact on direct gross value added (GVA) is calculated for UK vessels based on fleet segment-specific GVA as a percentage of fishing turnover from the Seafish fleet economic performance dataset and economic information from the Scientific, Technical and Economic Committee on Fisheries. Direct and indirect GVA and employment impacts are calculated using Type I multipliers from the Scottish Input-Output tables.
In relation to the export cables, impacts would be expected where export cable corridors intersect with important commercial fishing grounds for fisheries which use mobile demersal gear. There is uncertainty over the location of cable routes and so they are not assessed currently. Potential cable routes can be considered in future in relation to existing mobile demersal fishing grounds for over-15 m or over-12 m vessels, and under-15 m vessels (from Scotmap).
Method for assessment of changes in fishing patterns (arising from displacement) (arrays and cables): Any significant impacts would be an indirect effect arising from complete loss of or restricted access to traditional fishing grounds, and will therefore be a function of the level of impact from complete loss or restricted access to fishing grounds. Given that the assessment assumes that all landings affected are lost and there is no displacement, this is not assessed, but the potential impacts are noted under non-quantified impacts. This includes:
- Change in the costs and earning profile of vessels from additional steaming costs to reach alternative fishing grounds, changes in catch rates and target species;
- Other displacement impacts such as increased conflict between vessels, and different gear types.
Method for assessment of obstruction of fishing vessel navigation routes (arrays; cables): the potential impact of fishing vessels having to deviate around offshore arrays when steaming is assessed based on the estimated potential extra steaming distance and time and average fuel and labour costs for fishing vessels. This is covered in the assessment of impacts to commercial shipping (section E.10).
Method for assessment of fouling of fishing gear on cables or seabed infrastructure (cables – operation): Export cable routes are uncertain and it is therefore not possible to assess this at the present time. Cables are likely to be buried where possible and therefore impacts on commercial fishing should be minimised. An assessment of the potential for fouling of fishing gear should be carried out at project level, considering the seabed type inshore of DPOs (soft sediment in which cables may be buried or hard rock) and potential cable protection measures that might be required, and the use of mobile demersal gears, that might snag on cables or seabed infrastructure, and their penetration depths.
Method for assessment of consequential impacts to seafood processors: Any significant impacts on seafood processors would arise from a change in the availability of landings, and therefore is dependent on the outcome of the assessment of the complete loss of or restricted access to traditional fishing grounds. The potential impact on seafood processors is assessed for the combined impact of all DPOs in a region (i.e. not for individual DPOs, and scaled back in accordance with the regional scenarios).
The impact on individual ports is assessed based on the reduction in the value of landings to each Scottish port, in relation to the total value of landings to each port. This enables the analysis to reflect the fact that a reduction in a certain tonnage of landings to a small island port may have a greater impact on any associated processing activities at that port compared to a loss of the same value of landings to a larger port.
Data limitations: The available data under-represents fishing effort by under-12m vessels, which do not have VMS, and under-10 m vessels which do not have to submit logbooks. Under-12m vessels have submitted catch information on the Fish1 forms since 2017, but data are not available for the time period of the assessment (2013-2017). Information is available from Scotmap, however, this data represents information relating to fishing activity for the period 2007 to 2011 (collected by interviewing fishermen with 72% vessel coverage overall), and hence may no longer be representative of current inshore fishing effort. Furthermore, the coverage of Scotmap dataset varies by region. The distribution of landings from Scotmap, within each ICES rectangle, is therefore applied to the value of landings for each ICES rectangle, for the under-12m vessels. A comparison of Fish1 data for under-10m vessels aligns well with the distribution of landings from Scotmap. Additional investigation of plotter data provided by the industry has shown that the main fishing grounds are reflected in the VMS data used for the assessment of impacts on over-12m vessels. It is possible that the data used (2013-2017) do not fully capture existing or previous displacement of fishing activity from current offshore wind installations and those under construction, or management measures in marine protected areas. Comprehensive data on landings by ICES rectangle by non-EU vessels (e.g. Norwegian, Faroese) are not available.
E.6 Military Activities
DPO overlap with military danger areas (SW1, N1, N3, NE6, NE7, NE9, NE9) and exercise areas (W1). There is a need for further assessment of:
- Competition for space (arrays and cables); and
- Interference with underwater communication.
Method for competition for space (arrays and cables): Consultation is undertaken with the wind energy team of Ministry of Defence (MOD) Safeguarding Defence Infrastructure Organisation to establish whether there are any specific areas of concern, and the magnitude of any such concerns for the military defence sector, in relation to the proposed DPOs and export cables in relation to competition for space. This consultation also sought to establish whether any impacts could be quantitatively assessed.
Method for interference with underwater communications (arrays): Consultation is undertaken with the wind energy team of Ministry of Defence (MOD) Safeguarding Defence Infrastructure Organisation to establish whether there are any specific areas of concern, and the magnitude of any such concerns for the military defence sector, in relation to the proposed DPOs and potential interference with underwater communications. This consultation also sought to establish whether any impacts could be quantitatively assessed.
Data limitations: Identifying defence activities is relatively straightforward from national statistics. However, establishing whether defence activities are connected to marine activities is not possible. Furthermore, owing to the confidential nature of military defence activities it is difficult to assess the extent and frequency of activity and future trends within the marine environment. There are uncertainties concerning the exact location of training activities within designated exercise areas and the frequency of use of those areas given the need for a certain amount of security in the information provided. In some instances, the exact nature of Government spending changes is also uncertain and thus it is difficult to predict the future intensity of military activity within the marine environment.
E.7 Oil and Gas
There are spatial overlaps between existing oil and gas infrastructure and some DPO and also between some areas licensed for oil and gas production and DPO. Some DPO also lie inshore of existing and potential future oil and gas production areas. For spatial overlaps between existing oil and gas infrastructure and DPO it is assumed that:
- Renewables development will not be permitted within a given ‘corridor’ either side of existing infrastructure such as pipelines or platforms to enable existing infrastructure maintenance (or until such infrastructure is decommissioned); and
- The cost of any required cable/pipeline crossings with existing infrastructure will be borne by the renewables developer.
This would avoid any significant additional impacts to oil and gas operators.
There is a need for further assessment of:
- Competition for space – restricted access to seafloor (arrays);
- Competition for space – restriction on exploration activities (arrays); and
- Competition for space – obstruction of pipeline routes (arrays and export cables).
Method for competition for space – restricted access to seafloor (arrays): There is some minor spatial overlap between areas licensed for oil and gas development and certain AoS. It has been assumed that spatial planning within the DPO will avoid any significant interaction between oil and gas development within licensed blocks and potential offshore wind development. Consultation will be undertaken with Oil and Gas UK to identify any specific interactions of concern between licensed blocks and DPOs. As the areas are already licensed for oil and gas development, it is likely that this activity would be given priority over offshore wind development. This would reduce the area available for offshore wind development within the DPO but not to the extent that it compromised commercial viability.
Method for competition for space – restriction on exploration activities (arrays): There is some overlap between areas awarded under the 29th and 30th oil and gas licensing rounds and certain AoS. While activity under these awards will have completed or lapsed before any offshore wind development activity is initiated in the DPOs, the areas could be of future interest for oil and gas exploration. Offshore wind development in these DPOs could preclude further oil and gas exploration activity in these areas during the lifetime of the wind farm. This would represent a potential opportunity cost to the oil and gas sector, but this is not readily quantified. Only a small proportion of exploration studies lead to test drills and only a small proportion of test drills lead to field development. Such potential constraints are therefore recognised qualitatively in the assessment.
Method for competition for space – obstruction of pipeline routes (arrays and cables): Many of the AoS are located inshore of oil and gas fields. Should further field development occur which required the construction of new pipeline routes to shore, development within the DPOs could constrain these pipeline routes and increase the costs of the route. However, the North Sea oil and gas fields are mature and relatively few new discoveries would be expected in this region. In most cases, new development within existing fields would be likely to tie in to existing pipeline networks. Consultation will be undertaken with Oil and Gas UK to identify any specific issues of concern with the DPOs. Any issues identified will be reflected qualitatively in the assessment.
Data limitations: there is limited information on the potential locations of future oil and gas development and possible new pipeline routes. Information from the 29th and 30th award rounds indicates where current exploration activity is occurring and licensed blocks indicate where future development may possibly occur. Most oil and gas reserves in UK waters have been well studied and the potential for new development is considered to be quite limited, particularly in the North Sea.
E.8 Power Interconnectors
DPO or potential export cable routes overlap with planned future power interconnector routes. There is a need for further assessment of:
- Competition for space with potential future interconnectors (arrays and cables).
Method for competition for space (arrays and cables): For any DPO areas scoped into the assessment, it is assumed that the cost to the sector of having to ‘detour’ the future interconnector around the DPO is:
Length of deviation (km) X Average cost cable laying per km (£/km)
The average cost of cable laying is assumed to be £1.06m per km (2013 prices) (based on Annex H14 of Defra, 2012), which will be uprated to 2020 prices for the assessment. Consultation will be carried out with the relevant owners/promoters of planned interconnectors where required regarding potential routes and timing of development.
Data limitations: There is uncertainty regarding the routes and timing of development of potential future power interconnectors.
E.9 Recreational Boating
There are spatial overlaps between some sailing and cruising routes and certain DPO (SW1, SW2, W1, N1, N3, N5, NE6, NE7, NE9, NE10) Offshore wind development within AoS could affect these routes and act as a deterrent to investment. Development could also affect navigational safety. There is a need for further assessment of:
- Alterations to informal cruising routes (arrays);
- Deterrent to investment in marinas/supply chain (arrays); and
- Increase marine risk (arrays).
Method for alterations to informal cruising routes (arrays): the potential economic cost of recreational boats having to deviate around offshore arrays can be estimated based on the:
- Number of recreational transits across the area (e.g. from the AIS data), extrapolated to calculate annual recreational transits;
- Estimated extra distance for recreational vessel to deviate around an array; and
- Average fuel costs per nautical mile for recreational vessels.
Fuel type used in the assessment assumes red diesel, with an average unit pence per litre (ppl) of 112 ppl. The estimated difference in distance and associated fuel consumptions is costed for propulsion only, with no use for domestic fuel estimation. The mileage per litre for vessels under motor depends on the size and speed of the vessel in question, ranging from about 13-63 litres per hour. For the purposes of this assessment, fuel usage for a ‘generic’ averaged-sized boat at a consumption rate of 40 litres per hour travelling at a speed of 20 knots is used. In the assessment, all vessels are assumed to be under power (i.e., sailing boats are not assessed whilst ‘sailing’). It can be noted that this will likely overestimate of the cost impact on this sector as it assumes that all vessels deviating around an array are in transit under engine whereas some will be under sail.
Method for deterrent to investment in marinas/supply chain (arrays): The presence of arrays in close proximity to important cruising destinations has the potential to deter future investment. Consultation will be undertaken with RYA Scotland to identify any specific locations of concern with potential impacts assessed qualitatively. Where the cost of alterations to cruising routes is substantial, such that the usage of a route might be affected, the potential for marinas/supply chain activities related to that cruising route will be assessed qualitatively.
Method for increased marine risk: Radar interference from offshore wind installations is a known factor with respect to marine safety. This increase in marine risk is assessed qualitatively with comments regarding possible mitigation measures. Mitigation cost would be transferred to the developer and hence no quantitative assessment of this cost is undertaken. RYA Scotland will be consulted to ascertain whether there are any issues of particular concern for specific DPOs.
Data limitations: The recreational boating ‘heatmaps’ of intensity of use are based on AIS data. However, the proportion of recreational vessels which have AIS is relatively low. Furthermore, AIS data is monitored from terrestrial receiver stations. Reception range is therefore limited to line of sight and dependent on the power of the transmitting vessel (larger vessels with transmitters mounted higher up are more likely to be received than smaller vessels). Therefore, AIS coverage is better defined closer to shore, and AIS underestimates vessel activity outside of the reception range (i.e. further offshore). Additionally AIS reception in Scotland may be poor due to the steep terrain.
E.10 Shipping (Commercial)
The location of the AoS avoid most significant shipping routes, however, some AoS overlap with areas of medium shipping intensity in the West (W1, W3), and East (NE1) regions. There is a need for further assessment of:
- Obstruction of transiting vessel and/or ferry routes; increased steaming distances and time (arrays and cables).
Method for obstruction of transiting vessel and/or ferry routes; increased steaming distances and time (arrays, cables): the cost of displacement of commercial shipping/ferry routes can be assessed based on the number of vessels potentially displaced (based on AIS data), the estimated potential extra steaming distance and time and average fuel and labour costs for commercial vessels. The additional steaming distance is calculated by assuming that vessels will commence their direction change 10 km either side of the array area.
For both the ferry and commercial shipping routes, the fuel consumption rate is assumed to be 2,941 litres per hour at a speed of 20 knots. This is based on an average assumed vessel fuel consumption of 60 metric tonnes (MT) per day, or 2.5 MT per hour, for a large cargo vessel travelling at 20 knots, where 1 tonne (1,000 kilograms) equates to 1176.5 litres based on an average diesel fuel density of 0.820 kg/l. The density of diesel varies according to its grade, within this assessment, an average diesel fuel at 15ºC with a density of 0.820 kg/l is assumed.
For this costing assessment low sulphur fuel is used. The Baltic and North Sea sulphur Emission Control Area (ECA) established under MARPOL Annex VI, regulations 14 requires ships to use fuel oil with a sulphur content not in excess of 0.10%. The assessment uses a cost of circa $580 M/T. Therefore, the unit pence per litre (ppl) used in this assessment is taken to be 36.62 ppl. In addition, the use of this fuel for propulsion carries with it an additional duty of 10.11 ppl based on HMRC rates from 2019. Using the additional steaming distance and fuel price, the costs associated with the deviation and additional steaming distance is calculated as:
Additional steaming distance (in nautical miles) X fuel costs per nautical mile
The calculation uses an assumed average vessel speed to arrive at fuel consumption per vessel movement. To then infer the annual cost, the journey fuel consumption is multiplied by the average vessel transit count within the DPO area in one year, taken from AIS tracks for the first week of each month scaled up to reflect 52 weeks of activity. Prior to scaling, the AIS tracks are filtered, firstly to remove recreational vessels (used for the calculation under recreational boating above) and secondly to remove tracks which are less than 5% of the route length. Tracks which are less than 5% of the route length are assumed to be fragmented tracks, and therefore using these in the calculation may introduce double counting where multiple fragments of a single transit are calculated to each require the full diversion.
Data limitations: AIS A transmission is mandatory for commercial vessels above 300 GT and all passenger ships regardless of size. As a result, some vessel classifications are underrepresented in the AIS data, including: commercial vessels below 300 GT; recreational vessels, fishing vessels and naval vessels on deployment. AIS B is optional and may be carried by smaller vessels including recreational, fishing and smaller commercial craft. AIS data collected by the Maritime and Coastguard Agency is monitored from terrestrial receiver stations. Reception range is therefore limited to line of sight and dependent on the power of the transmitting vessel (hence, larger vessels with transmitters mounted higher up are more likely to be received than smaller vessels). Therefore, AIS coverage is greater closer to shore, and AIS may underestimate vessel activity outside of the reception range (i.e. further offshore).
A range of variables affect the fuel burned per hour. These include ship type and size, the precise fuel type and grade being used, different engine types, the age and service history of engines, met-ocean effects, the vessel hull hydrodynamic and the wider economic pressures which dictating vessel speed. For example, slow steaming is currently a technique used by Commercial Shipping operators to minimise fuel, as significant cost savings results from sailing at 12 knots instead of 24 knots. This has become a commonly deployed measure for addressing shipping costs in response to recent economic pressures and fluctuating fuel costs.
E.11 Telecom Cables
DPO overlap with existing telecom cables (NE8 and NE9). There is a need for further assessment of:
- Competition for space with potential future telecom cables (arrays and cables).
Method for competition for space (arrays, cables): Existing telecom cables need to be replaced periodically (approximately every 25 years), and new telecom cables may be required. Further consideration will be given to the potential socio-economic impacts in consultation with the relevant telecom cable owner/promoter, including the replacement of cables in relation to the potential timing of offshore wind development. For any DPO area scoped into the assessment, the cost to the sector of having to ‘detour’ a future telecom cable around a DPO can be assessed as:
Length of deviation (km) X Average cost cable laying per km (£/km)
Data limitations: there is little information available on how this sector may change in the future (future telecom cables) and on the timing of replacement of existing cables.
Where existing telecom cables may require replacement, it is assumed that any development within the DPO will be required to leave a cable corridor along the cable route, and that there would be no requirement to divert the cable upon replacement.
There is the potential for significant impacts to landscapes, seascapes and viewpoints where offshore wind turbines are visible to receptors (i.e. people) and hence the potential for subsequent indirect impacts on tourism if this leads to avoidance of the area. As landscape and visual issues are often the most prominent reason for public objection to both land-based and offshore wind farms, there is a need for further assessment of:
- Impacts to landscape or seascape – long term (arrays).
Method for impacts to landscape or seascape – long term (arrays): The methodology below uses regional tourism expenditure values sourced from VisitScotand. These values are adjusted for GDP to provide baseline regional tourism expenditure values for 2020. For the purposes of this assessment, it is assumed that tourism levels will remain constant in real terms over the period assessed (i.e. there will be no growth in tourism volume and value).
The potential impact on tourism expenditure within each region is then calculated based on the following, and applied to the years in the assessment period when arrays would be constructed and operational:
- The total tourism spend (£million) within the most relevant VisitScotland regions(s) are identified for the DPOs scoped into the assessment;
- The Zone of Influence (ZOI; the zone within which landscape and visual impacts arising from the array may result in a reduction in visitor numbers and hence expenditure) is calculated by measuring the land area which fell within the buffer zone around each DPO that is within 15 m of land. The buffer used was 18 km around each DPO.
The proportion of the VisitScotland regional area within the ZOI is calculated as:
Land area within the ZOI (km2) / Total land area within the VisitScotland region (km2)
The value of tourism expenditure within the ZOI is firstly scaled based on the housing density within a parish and subsequently calculated as:
Total VisitScotland regional value(£millions) X proportion of dwellings within parish X proportion of parish area within ZOI
From the available evidence base, the reduction in tourism spending due to negative impacts is assumed to be 1.30% (values based on Riddington et al., 2008). As a precautionary approach it is assumed that these reductions are not negated by any positive impacts. The estimated loss of general tourism-related expenditure is then calculated as:
Value of tourism expenditure within the ZOI X 0.013
Data limitations: there is limited evidence relating to the impact of offshore wind farms on local or regional tourism. The assessment has used information on the estimated impact of onshore windfarms on tourism together with evidence-based judgements on the spatial extent of potential impacts from offshore wind farms.
E.13 Water Sports
There is the potential for DPO areas to overlap with recreational angling sites (the majority of which occur within 6 NM of the coast. Several AoS overlap within 6 NM of the coast in the South West, West and North regions (SW1, SW2, W1, N4). Other watersports such as surfing, windsurfing, shore-based angling or kayaking are mainly undertaken inshore, and scuba diving is generally undertaken at discreet diving sites such as wrecks or areas with interesting and rich marine life or seascapes. There is a need for further assessment of:
- Displacement due to spatial overlap between array and recreational angling activity (arrays).
Method for displacement due to spatial overlap between array and recreational angling (arrays): the potential economic cost of the loss of marine space for recreational sea angling can be estimated based on the total reduction in expenditure/loss of income, calculated by multiplying the percentage loss of area (to arrays) within 6 nm, by the estimated value of boat-based sea angling in the relevant region (derived from Radford et al., 2009).
Data limitations: In general, data on the distribution and intensity of marine watersport activities is limited. In the Scottish Marine Recreation and Tourism Survey, low response rates to the survey for a minority of activities mean that some spatial information is incomplete. Furthermore, the smaller number of responses covering remoter parts of Scotland means that spatial information for areas such as the Western Isles and Shetland is also likely to be partial.