Decommissioning Phase

Magnitude of Impact
  1. The presence of the infrastructure within the Proposed Development fish and shellfish ecology study area will result in long-term habitat loss. The maximum design scenario is for up to 7,562,609 m2 of permanent habitat loss due to the scour protection associated with wind turbine and OSP/Offshore convertor substation platform foundations and cable protection associated with array, OSP/Offshore convertor substation platform interconnector and offshore export cables being left in situ after decommissioning. This equates to a small proportion (0.6%) of the Proposed Development fish and shellfish ecology study area.
  2. The impact is predicted to be of local spatial extent, long term duration, continuous and not reversible. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the Receptor
  1. The sensitivity of the fish and shellfish IEFs, for both marine and diadromous species, can be found in the construction and operation and maintenance phase assessment above (paragraph 207 et seq.).
Significance of the effect

Marine Species

  1. For most fish and shellfish IEF species, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
  2. For European lobster and Nephrops, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  3. For sandeel, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Diadromous Species

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Secondary Mitigation and Residual Effect
  1. No additional fish and shellfish ecology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

Electromagnetic Fields from subsea electrical cabling

  1. The installation of inter-array, interconnector and offshore export cables will result in either High Voltage Alternating Current (HVAC) or High Voltage Direct Current (HVDC) under the maximum design scenario (see Table 9.15   Open ▸ ). The conduction of electricity through subsea power cables will result in emission of localised EMFs which could potentially affect the sensory mechanisms of some species of fish and shellfish, particularly electrosensitive species (including elasmobranchs) and diadromous fish species (Centre for Marine and Coastal Studies (CMACS), 2003).

Operation and Maintenance Phase

Magnitude of Impact
  1. The presence and operation of inter-array, interconnector and offshore export cables within the Proposed Development fish and shellfish ecology study area will result in emission of localised EMFs affecting fish and shellfish IEFs. EMF comprise both the electrical (E) fields, measured in volts per metre (V/m), and the magnetic (B) fields, measured in microtesla (µT) or milligauss (mG). Background measurements of the magnetic field are approximately 50 μT in the North Sea, and the naturally occurring electric field in the North Sea is approximately 25 μV/m (Tasker et al., 2010).
  2. It is common practice to block the direct electrical field (E) using conductive sheathing, meaning that the EMFs that are emitted into the marine environment are the magnetic field (B) and the resultant induced electrical field (iE). It is generally considered impractical to assume that cables can be buried at depths that will reduce the magnitude of the B field, and hence the sediment-sea water interface iE field, to below that at which these fields could be detected by certain marine organisms on or close to the seabed (Gill et al., 2005; Gill et al., 2009). By burying a cable, the magnetic field at the seabed is reduced due to the distance between the cable and the seabed surface as a result of field decay with distance from the cable (CSA, 2019).
  3. A variety of design and installation factors affect EMF levels in the vicinity of the cables. These include current flow, distance between cables, cable orientation relative to the earth’s magnetic field (DC only), cable insulation, number of conductors, configuration of cable and burial depth. Clear differences between AC and DC systems are apparent: the flow of electricity associated with an AC cable changes direction (as per the frequency of the AC transmission) and creates a constantly varying electric field in the surrounding marine environment (Huang, 2005). Conversely, DC cables transmit energy in one direction creating a static electric and magnetic field. Average magnetic fields of DC cables are also higher than those of equivalent AC cables ( Table 9.27   Open ▸ ).
  4. The strength of the magnetic field (and consequently, induced electrical fields) decreases rapidly horizontally and vertically with distance from source. A recent study conducted by CSA (2019) found that inter-array and offshore export cables buried between depths of 1 m to 2 m reduces the magnetic field at the seabed surface four-fold. For cables that are unburied and instead protected by thick concrete mattresses or rock berms, the field levels were found to be similar to buried cables.
  5. CSA (2019) found magnetic field levels directly over live AC undersea power cables associated with offshore wind energy projects range between 65 mG (at seafloor) and 5 mG (1 m above sea floor) for array cables. and 165 mG (at seafloor) and 10 mG (1 m above seafloor) for offshore export cables. At lateral distances from the cable, magnetic fields greatly reduced at the sea floor to between 10 mG and <0.1 mG (from 3 to 7.5 m respectively) for array cables, and at 1 m above the sea floor, magnetic fields reduced to between 15 mG and <0.1 mG (from 3 to 7.5 m respectively) for offshore export cables.
  6. The induced electric fields directly over live AC undersea power cables ranged between 1.7 mV/m (at seafloor) and 0.1 mV/m (1 m above seafloor) for array cables and 3.7 mV/m (at seafloor) and 0.2 mV/m (1 m above seafloor) for offshore export cables (CSA, 2019). At lateral distances electric fields at the sea floor reduced to between 0.01 mV/m and 1.1 mV/m (from 3 to 7.5 m respectively) for array cables and 1 m above the sea floor, the magnetic fields reduced to between 0.02 mV/m and 1.3 mV/m (from 3 to 7.5 m respectively) for offshore export cables. This pattern of reduction in the level of magnetic fields with increasing lateral and vertical distance from offshore export cables as described above is visually displayed in Figure 9.10   Open ▸ . Higher colour density of rings demonstrate where magnetic field is strongest, with weaker colour density demonstrating weak magnetic fields (CSA, 2019), with increasing distance from the cable ( Figure 9.10   Open ▸ ).

Figure 9.10:
Illustration of Magnetic Field Reduction with Distance, both Laterally and Vertically, from Undersea Inter-array Power Cable (reproduced from CSA, 2019)

Figure 9.10: Illustration of Magnetic Field Reduction with Distance, both Laterally and Vertically, from Undersea Inter-array Power Cable (reproduced from CSA, 2019)

 

  1. Normandeau et al. (2011) provided additional data ( Table 9.27   Open ▸ ) demonstrating the rapid drop off of magnetic fields with increasing vertical and horizontal distance from both AC and DC cables. This supports the findings from the CSA (2019) study, with AC cables ranging from 7.85 μT on the seafloor with no horizontal distance to 0.08 μT at 10 m above the seafloor and 10 m horizontal distance. DC cables showed a similar decrease albeit starting from a higher level with cables ranging from 78.27 μT on the seafloor with no horizontal distance to 0.46 μT at 10 m above the seafloor and 10 m horizontal distance.

 

Table 9.27:
Average Magnetic Fields (μT) Generated for AC and DC Offshore Export Cables at Horizontal Distances from the Cable (Assuming Cable Burial to a Depth of 1 m; Source: Modified from Normandeau et al., 2011)

Table 9.27: Average Magnetic Fields (μT) Generated for AC and DC Offshore Export Cables at Horizontal Distances from the Cable (Assuming Cable Burial to a Depth of 1 m; Source: Modified from Normandeau et al., 2011)

 

  1. The impact is predicted to be of local spatial extent (i.e. within a few metres of buried cables), long term duration, continuous and not reversible during the operation and maintenance phase (impact is reversible upon decommissioning). It is predicted that the impact will affect fish and shellfish IEFs directly. The magnitude is therefore considered to be low.
Sensitivity of the Receptor

Marine Species

  1. Fish and shellfish species (particularly elasmobranchs) are able to detect applied or modified magnetic fields. Species for which there is evidence of a response to E and/or B fields include elasmobranchs (sharks, skates and rays), and plaice (Gill et al., 2005; CSA, 2019). It can be inferred that the life functions supported by an electric sense may include detection of prey, predators or conspecifics to assist with feeding, predator avoidance, and social or reproductive behaviours. Life functions supported by a magnetic sense may include orientation, homing, and navigation to assist with long or short-range migrations or movements (Gill et al., 2005; Normandeau et al., 2011).
  2. Studies examining the effects of EMF from AC undersea power cables on fish behaviours have been conducted to determine the thresholds for detection and response to EMF. Table 9.28   Open ▸ provides a summary of the scientific studies conducted to assess sensitivity of EMF on varying fish species.

 

Table 9.28:
Relationship between Geomagnetic Field Detection Electrosensitivity, and the Ability to Detect 50/60-Hz AC Fields in Common Marine Fish and Shellfish Species (Adapted from CSA, 2019)

Table 9.28: Relationship between Geomagnetic Field Detection Electrosensitivity, and the Ability to Detect 50/60-Hz AC Fields in Common Marine Fish and Shellfish Species (Adapted from CSA, 2019)

 

  1. A number of field studies have observed behaviours of fish and other species around AC submarine cables in the U.S.A. (see citations in Table 9.28   Open ▸ ). Observations at three energized 35-kV AC undersea power cable sites off the coast of California that run from three offshore platforms to shore, which are unburied along much of the route, did not show that fish were repelled by or attracted to the cables (Love et al., 2016) (it should be noted that these cables are significantly lower voltage than the maximum design scenario for the Proposed Development). A study investigating the effect of EMF on lesser sandeel larvae spatial distribution found that there was no effect on the larvae (Cresci et al., 2022), and a further study concluded the same for herring (Cresci et al.,2020).
  2. Elasmobranchs (i.e. sharks, skates and rays) are known to be the most electro-receptive of all fish. These species possess specialised electro-receptors which enable them to detect very weak voltage gradients (down to 0.5 μV/m) in the environment naturally emitted from their prey (Gill et al., 2005). Both attraction and repulsion reactions to E-fields have been observed in elasmobranch species. Spurdog, an elasmobranch species known to occur within the Proposed Development fish and shellfish ecology study area, avoided electrical fields at 10 μV/cm (Gill and Taylor, 2001), although it should be noted that this level (i.e. 10 μV/cm is equivalent to 1,000 μV/m) is considerably higher than levels associated with offshore electrical cables (see paragraph 238). A COWRIE-sponsored mesocosm study demonstrated that the lesser spotted dogfish and thornback ray were able to respond to EMF of the type and intensity associated with subsea cables; the responses of some ray individuals suggested a greater searching effort when the cables were switched on (Gill et al., 2009). However, the responses were not predictable and did not always occur (Gill et al., 2009). In another study, EMF from 50/60-Hz AC sources appears undetectable in elasmobranchs. Kempster et al. (2013) reported that small sharks could not detect EMF produced at 20 Hz and above, and a magnetic field of 14,300 mG produced by a 50 Hz source had no effect on bamboo shark (Scyliorhinidae, a group that includes catsharks and dogfish) behaviour.
  3. Crustacea, including lobster and crab, have been shown to demonstrate a response to B fields, with the Caribbean spiny lobster Panulirus argus shown to use a magnetic map for navigation (CSA, 2019). EMF exposure has been shown to result in varying egg volumes for edible crabs compared to controls. Exposed larvae were significantly smaller, but there were no statistically significant differences in hatched larval numbers, deformities, mortalities, or fitness (Scott, 2019). Exposure to EMF has also been shown to affect a variety of physiological processes within crustaceans. For example, Lee and Weis demonstrated that EMF exposure affected moulting in fiddler crabs (Uca pugilator and Uca pugnax) (Lee and Weis, 1980). Several studies have also suggested that EMFs affect serotonin regulation which may affect the internal physiology of crustaceans potentially leading to behavioural changes, although such changes have not been reported (Atema and Cobb, 1980; Scrivener, 1971). Crab movement and location inside large cages has been reported to be unaffected by proximity to energized AC undersea power cables off southern California and in Puget Sound, indicating crabs also were not attracted to or repelled by energized AC undersea power cables that were either buried or unburied (Love et al., 2016). However, studies on the Dungeness crab and edible crab have reported behavioural changes during exposure to increased EMF and both species showed increased activity when compared to crabs that were not exposed (Scott et al., 2018; Woodruff et al., 2012). Crabs may also spend less time buried, a natural predator avoidance behaviour (Rosaria and Martin, 2010).
  4. It is uncertain if other crustaceans including commercially important European lobster and Nephrops are able to respond to magnetic fields in this way. Limited research undertaken with the European lobster found no neurological response to magnetic field strengths considerably higher than those expected directly over an average buried power cable (Normandeau et al., 2011; Ueno et al., 1986). A field study by Hutchison et al. (2018) observed the behaviour of American lobster (a magneto-sensitive species) to DC and AC fields from a buried cable and found that it did not cause a barrier to movement or migration, as both species were able to freely cross the offshore cable route. However, lobsters were observed to make more turns when near the energised cable. Adult lobsters have been shown to spend a higher percentage of time within shelter when exposed to EMF. European lobsters exposed to EMF have also been found to have a significant decrease in egg volume at later stages of egg development and more larval deformities (Scott, 2020).
  5. Scott et al. (2020) presents a review of the existing papers on the impact of EMF on crustacean species. Of the papers reviewed by Scott et al. (2020), three studied EMF effects on fauna in the field, the rest were laboratory experiments which directly exposed the target fauna to EMF (Scott et al., 2020). These laboratory experiments, while giving us an indication of crustacean behaviour to EMF, may be less applicable in the context of subsea cables in the marine environment. Of the field experiments, one demonstrated that lobsters have a magnetic compass by tethering lobsters inside a magnetic coil (Lohmann et al., 1995), one focused on freshwater crayfish and put magnets within the crayfish hideouts (Tański et al., 2005), and the last one looked at shore crabs at an offshore wind farm and found no adverse impact on the population. The two former papers are not applicable to offshore wind farm subsea cables and the latter found no adverse impact on the population of shore crabs from the offshore wind farm (Langhamer et al., 2016).
  6. Further research by Scott et al. (2021) found that physiological and behavioural impacts on edible crab occurred at 500 μT and 1000 μT, causing disruption to the L-Lactate and D-Glucose circadian rhythm and altering Total Haemocyte Count, and also causing attraction to EMF exposed areas and reduced roaming time. However, these physiological and behavioural effects did not occur at 250 μT. Seeing as even in the event of an unburied cable the maximum magnetic field reported was 78.27 μT (Normandeau et al., 2011), it can be assumed that the magnetic fields generated by the offshore export cables will be lower than 250 μT, and therefore will not present any adverse effects on edible crab. Harsanyi et al. (2022) noted that chronic exposure to EMF effects could lead to physiological deformities and reduced swimming test rates in lobster and edible crab larvae. However, these deformities were in response to EMF levels of 2,800 μT and therefore are higher than EMF effects expected for buried and unburied cables. The report recommends burying of cables in order to reduce any potential impacts associated with high levels of EMF.
  7. In summary, the range over which these species can detect electric fields is limited to centimetres, rather than metres, around these species (CSA, 2019). Pelagic species generally swim well above the seafloor and can be expected to rarely be exposed to the EMF at the lowest levels from AC undersea power cables buried in the seafloor, resulting in impacts that would therefore be localised and transient. Demersal species (e.g. skates) that dwell on the bottom, will be closer to the undersea power cables and thus encounter higher EMF levels when near the cable. Demersal species and shellfish are also likely to be exposed for longer periods of time and may be largely constrained in terms of location. However, the rapid decay of the EMF with horizontal distance (i.e. within metres) minimises the extent of potential impacts. Finally, fish that can detect the Earth’s magnetic field are unlikely to be able to detect magnetic fields produced by 50/60-Hz AC power cables and therefore these species are unlikely to be affected in the field (CSA, 2019).
  8. Marine fish and shellfish ecology IEFs in the Proposed Development fish and shellfish ecology study area are deemed to be of low to medium vulnerability, high recoverability and local to national importance. The sensitivity of the receptor is therefore, considered to be low (most fish and shellfish IEFs) to medium (decapod crustaceans and elasmobranchs).

Diadromous Species

  1. EMF may also interfere with the navigation of sensitive diadromous species. Species for which there is evidence of a response to E and/or B fields include river lamprey, sea lamprey, European eel, and Atlantic salmon (Gill et al., 2005; CSA, 2019). Lampreys possess specialised ampullary electroreceptors that are sensitive to weak, low frequency electric fields (Bodznick and Northcutt, 1981; Bodznick and Preston, 1983), but information regarding what use they make of the electric sense is limited. Chung-Davidson et al. (2008) found that weak electric fields may play a role in the reproduction of sea lamprey and it was suggested that electrical stimuli mediate different behaviours in feeding-stage and spawning-stage individuals. This study (Chung-Davidson et al., 2008) showed that migration behaviour of sea lamprey was affected (i.e. adults did not move) when stimulated with electrical fields of intensities of between 2.5 and 100 mV/m, with normal behaviour observed at electrical field intensities higher and lower than this range. It should be noted, however, that these levels are considerably higher than modelled induced electrical fields expected from AC subsea cables (see Table 9.27   Open ▸ ).
  2. Atlantic salmon and European eel have both been found to possess magnetic material of a size suitable for magnetoreception, and these species can use the earth’s magnetic field for orientation and direction finding during migration (Gill and Bartlett, 2010; CSA, 2019). Mark and recapture experiments undertaken at the Nysted operation offshore wind farm showed that eel did cross the offshore export cable (Hvidt et al., 2003) but studies on European eel in the Baltic Sea have highlighted some limited effects of subsea cables (Westerberg and Lagenfelt, 2008). The swimming speed during migration was shown to change in the short term (tens of minutes) with exposure to AC electric subsea cables, even though the overall direction remained unaffected (Westerberg and Langenfelt, 2008). The authors concluded that any delaying effect (i.e. on average 40 minutes) would not be likely to influence fitness in a 7,000 km migration. Research in Sweden on the effects of a HVDC cable on the migration patterns of a range of fish species, including salmonids, failed to find any effect (Westerberg et al., 2007; Wilhelmsson et al., 2010). Research conducted at the Trans Bay cable, a DC undersea cable near San Francisco, California, found that migration success and survival of chinook salmon (Oncorhynchus tshawytscha) was not impacted by the cable. However, as with the Hutchison et al. (2018) study on lobster (paragraph 246), behavioural changes were noted when these fish were near the cable (Kavet et al., 2016) with salmon appearing to remain around the cable for longer periods. These studies demonstrate that while DC undersea power cables can result in altered patterns of fish behaviour, these changes are temporary and do not interfere with migration success or population health.
  3. Table 9.29   Open ▸ provides a summary of the scientific studies conducted to assess sensitivity of EMF on varying fish species.

 

Table 9.29:
Relationship between Geomagnetic Field Detection Electrosensitivity, and the Ability to Detect 50/60-Hz AC Fields in Diadromous Fish Species (Adapted from CSA, 2019)

Table 9.29: Relationship between Geomagnetic Field Detection Electrosensitivity, and the Ability to Detect 50/60-Hz AC Fields in Diadromous Fish Species (Adapted from CSA, 2019)

 

  1. Diadromous fish IEFs in the Proposed Development fish and shellfish ecology study area are deemed to be of low vulnerability, high recoverability and national to international importance. The sensitivity of the receptor is therefore, considered to be low.
Significance of the Effect

Marine Species

  1. For most fish and shellfish IEF species, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
  2. For European lobster Nephrops edible crab and elasmobranchs, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Diadromous Species

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
Secondary Mitigation and Residual Effect
  1. No additional fish and shellfish ecology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

Colonisation of foundations, scour protection and cable protection

  1. Foundation, cable protection and scour protection components of offshore wind farms can be viewed as artificial reefs, as these add hard substrate to areas typically characterised by soft, sedimentary environments. Man-made structures placed on the seabed attract many marine organisms including benthic species normally associated with hard substrates and therefore, may have indirect effects on fish and shellfish populations through their potential to act as artificial reefs and to bring about changes to food resources (Inger et al., 2009). Additionally, man-made structures may also have direct effects on fish through their potential to act as fish aggregation devices (Petersen and Malm, 2006).

Operation and Maintenance Phase

Magnitude of Impact
  1. The presence of infrastructure within the Proposed Development fish and shellfish ecology study area may result in the colonisation of foundations, scour protection and cable protection. The maximum design scenario is for up to 10,198,971 m2 of habitat created due to the installation of jacket foundations, associated scour protection and cable protection associated with inter-array cables, OSP/Offshore convertor substation platform interconnector cables and offshore export cables ( Table 9.15   Open ▸ ). This value however is likely an over estimation of habitat creation as it is based on solid panels being used for the 317 jacket foundations. The four sides of these jackets will be made of a lattice structure; however the precise dimensions of these lattices are unknown at the time of writing, therefore a solid structure has been assumed from the values available, noting that this will result in an overestimate of the habitat created. It is expected that the foundations and scour and cable protection will be colonised by species already occurring in the benthic subtidal and intertidal ecology study area (e.g. tunicates, bryozoa sp., mussels and barnacles which are typical of temperate seas; see volume 2, chapter 8). The increased availability of prey species may lead to increased numbers of fish and shellfish species utilising the additional prey resource and hard substrate habitats. In addition, this may lead to further effects to higher trophic levels, including marine mammals and birds, the implications of which are further discussed in volume 2, chapter 10 and volume 2, chapter 11.
  2. These effects are only considered in the operation and maintenance phase as it takes time for organisms to colonisation a structure post-installation.
  3. The impact is predicted to be of local spatial extent, long term duration (35-year operation phase), continuous and medium reversibility. It is predicted that the impact will affect the receptor both directly and indirectly. The magnitude is therefore considered to be low.
Sensitivity of the Receptor

Marine Species

  1. Hard substrate habitat created by the introduction of wind turbine foundations and scour/cable protection are likely to be primarily colonised within hours or days after construction by demersal and semi-pelagic fish species (Andersson, 2011). Continued colonisation has been seen for a number of years after the initial construction, until a stratified recolonised population is formed (Krone et al., 2013). Feeding opportunities or the prospect of encountering other individuals may attract fish aggregate from the surrounding areas, which may increase the carrying capacity of the area (Andersson and Öhman, 2010; Bohnsack, 1989).
  2. The dominant natural substrate character of the Proposed Development fish and shellfish ecology study area (e.g. soft sediment or hard rocky seabed) will determine the number of new species found on the introduced vertical hard surface and associated scour protection. When placed on an area of seabed which is already characterised by rocky substrates, few species will be added to the area, but the increase in total hard substrate could sustain higher abundance (Andersson and Öhman, 2010). Conversely, when placed on a soft seabed, most of the colonising fish will be normally associated with rocky (or other hard bottom) habitats, thus the overall diversity of the area may increase (Andersson et al., 2009). A new baseline species assemblage will be formed via recolonisation and the original soft-bottom population will be displaced (Desprez, 2000). This was observed in studies by Leonhard et al. (Danish Energy Agency, 2012) at the Horns Rev offshore wind farm, and Bergström et al. (2013) at the Lillgrund offshore wind farm. An increase in fish species associated with reefs such as goldsinny wrasse Ctenolabrus rupestris, lumpsucker Cycloplerus lumpus and eelpout Zoarces viviparous, and a decrease in the original sandy-bottom fish population were reported (Danish Energy Agency, 2012; Bergström et al., 2013). A decrease in soft sediment species is contradictory to findings of Degraer et al. (2020) where an increase in density of soft sediment species was seen, although this increase may be related to reduced fishing pressure within the array. However it is noted by Degraer et al. (2020) that these effects were site specific and therefore may not necessarily be extrapolated to other offshore wind farms (see paragraph 210 for further information on increases of crustacean species associated with installation of an offshore wind development).
  3. The longest monitoring programme conducted to date at the Lillgrund offshore wind farm in the Öresund Strait in southern Sweden, showed no overall increase in fish numbers, although redistribution towards the foundations within the offshore wind farm area was noticed for some species (i.e. cod, eel and eelpout; Andersson, 2011). More species were recorded after construction than before, which is consistent with the hypothesis that localised increases in biodiversity may occur following the introduction of hard substrates in a soft sediment environment. Overall, results from earlier studies reported in the scientific literature did not provide robust data (e.g. some were visual observations with no quantitative data) that could be generalised to the effects of artificial structures on fish abundance in offshore wind farm areas (Wilhelmsson et al., 2010). More recent papers are, however, beginning to assess population changes and observations of recolonisation in a more quantitative manner (Krone et al., 2013).
  4. There is uncertainty as to whether artificial reefs facilitate recruitment in the local population, or whether the effects are simply a result of concentrating biomass from surrounding areas (Inger et al., 2009). Linley et al. (2007) concluded that finfish species were likely to have a neutral to beneficial likelihood of benefitting, which is supported by evidence demonstrating that abundance of fish can be greater within the vicinity of wind turbine foundations than in the surrounding areas, although species richness and diversity show little difference (Wilhelmsson et al., 2006a; Inger et al., 2009). A number of studies on the effects of vertical structures and offshore wind farm structures on fish and benthic assemblages have been undertaken in the Baltic Sea (Wilhelmsson et al., 2006a; 2006b). These studies have shown evidence of increased abundances of small demersal fish species (including gobies Gobidae, and goldsinny wrasse) in the vicinity of structures, most likely due to the increase in abundance of epifaunal communities which increase the structural complexity of the habitat (e.g. mussels and barnacles Cirripedia spp.). It was speculated that in true marine environments (e.g. the North Sea), offshore wind farms may enhance local species richness and diversity, with small demersal species such as gobies providing prey items for larger, commercially important species including cod (which have been recorded aggregating around vertical steel constructions in the North Sea; Wilhelmsson et al., 2006a). Monitoring of fish populations in the vicinity of an offshore wind farm off the coast of the Netherlands indicated that the offshore wind farm acted as a refuge for at least part of the cod population (Lindeboom et al., 2011; Winter et al., 2010).
  5. In contrast, post construction fisheries surveys conducted in line with the Food and Environmental Protection Act (FEPA) licence requirements for the Barrow and North Hoyle offshore wind farms, found no evidence of fish abundance across these sites being affected, either beneficially or adversely, by the presence of the offshore wind farms (Cefas, 2009; BOWind, 2008) therefore suggesting that any effects, if seen, are likely to be highly localised and while of uncertain duration, the evidence suggests effects are not adverse.
  6. It is likely that the greatest potential for beneficial effects exist for crustacean species, such as crab and lobster, due to expansion of their natural habitats (Linley et al., 2007) and the creation of additional refuge areas. Where foundations and scour protection are placed within areas of sandy and coarse sediments, this will represent novel habitat and new potential sources of food in these areas and could potentially extend the habitat range of some shellfish species. Post-construction monitoring surveys at the Horns Rev offshore wind farm noted that the hard substrates were used as a hatchery or nursery grounds for several species, and was particularly successful for brown crab (BioConsult, 2006). They concluded that larvae and juveniles rapidly invade the hard substrates from the breeding areas (BioConsult, 2006). As both crab and lobster are commercially exploited in the vicinity of the Proposed Development fish and shellfish ecology study area, there is potential for benefits to the fisheries, depending on the materials used in construction of the offshore wind farm.
  7. Other shellfish species, such as the blue mussel Mytilus edulis, have the potential for great expansion of their normal habitat due to increased hard substrate in areas of sandy habitat. Krone et al. (2013) coined the term 'Mytilusation' to describe this mass biofouling process recorded at a platform in the German Bight, North Sea. It was found that over a three-year period, almost the entire vertical surface of area of the platform piles had been colonised by three key species blue mussel, the amphipod Jassa spp. and anthozoans (mainly Metridium senile). These three species were observed to occur in depth-dependant bands, attracting pelagic fish species such as horse mackerel Trachurus trachurus and demersal pouting Trisopterus luscus in great numbers. Layers of shell detritus were visible at the base of the foundations due to the mussel populations above and both velvet swimming crab and brown crabs were recorded here. These species were not typical of baseline species assemblage, providing further evidence of localised changes in fish and shellfish assemblages in the vicinity of foundation structures.
  8. The colonisation of new habitats may potentially lead to the introduction of invasive and non-native species species (see volume 2, chapter 8 for detailed discussion). With respect to fish and shellfish populations, this may have indirect adverse effects on shellfish populations as a result of competition. However, no invasive and non-native species species were identified as present in the area during surveys across the Proposed Development fish and shellfish ecology study area. There is little evidence of adverse effects on fish and shellfish IEFs resulting from colonisation of other offshore wind farms by invasive and non-native species species. The post construction monitoring report for the Barrow offshore wind farm demonstrated no evidence of invasive and non-native species species on or around the monopiles (EMU, 2008a), and a similar study of the Kentish Flats monopiles only identified slipper limpet Crepidula fornicata (EMU, 2008b). Potential adverse effects of the introduction of invasive and non-native species species are discussed in detail in volume 2, chapter 8.
  9. Marine fish and shellfish ecology IEFs in the Proposed Development fish and shellfish ecology study area are deemed to be of low vulnerability, and local to national importance (recoverability is not relevant to this impact during the operation maintenance phase). The sensitivity of the receptor is therefore, considered to be low.

Diadromous Species

  1. Diadromous species that are likely to interact with the Proposed Development fish and shellfish ecology study area are only likely to do so by passing through the area during migrations to and from rivers located on the east coast of Scotland, such as to rivers with designated sites, with diadromous fish species listed as qualifying features, as presented in volume 3, appendix 9.1. In most cases, it is expected that diadromous fish are unlikely to utilise the increase in hard substrate within the Proposed Development fish and shellfish ecology study area for feeding or shelter opportunities as they are only likely to be in the vicinity when passing through during migration.
  2. However, there is potential for impacts upon diadromous fish species resulting from increased predation by marine mammal species within offshore wind farms. Tagging of harbour seal Phoca vitulina and grey seal Halichoerus grypus around Dutch and UK wind farms provided significant evidence that the seal species were utilising wind farm sites as foraging habitats (Russel et al., 2014), specifically targeting introduced structures such as wind turbine foundations. However, a further study using similar methods concluded that there was no change in behaviour within the wind farm (McConnell et al., 2012), so it is not certain exactly to what extent seals utilise offshore wind developments and therefore effects may be site specific. Assuming that seals do utilise offshore wind developments as foraging areas, diadromous fish species may be impacted by the increased predation in an area where predation was lower prior to development. It is, however, unlikely that this would result in significant predation on diadromous species. Research has shown that Atlantic salmon smolts spend little time in the coastal waters, and instead are very active swimmers in coastal waters, making their way to feeding grounds in the north quickly (Gardiner et al., 2018a; Gardiner et al., 2018a; Newton et al., 2017; Newton et al., 2019; Newton et al., 2021) (see volume 3, appendix 9.1 for further detail on Atlantic salmon migration). Due to the evidence that Atlantic salmon tend not to forage in the coastal waters of Scotland, it is unlikely that they will spend time foraging around wind turbine foundations and therefore are at low risk of impact from increased predation from seals and other predators.
  3. Sea trout may be at higher risk of increased predation from seals than Atlantic salmon due to their higher usage of coastal environments. Sea trout are generalist, opportunistic feeders with their diet comprising mainly of fish, crustaceans, polychaetes and surface insects with proportion of each of these prey categories varying dependent on season (Rikardsen et al., 2006; Knutsen et al., 2001). Due to the potential for increase in juvenile crustacean species and other shellfish species (see paragraphs 268 and 269) which are potential prey items from sea trout, it is possible that foraging sea trout may be attracted to the hard substrates introduced by installation of the Proposed Development. This attraction could in turn lead to increased predation of seal species upon sea trout species. However, there is little evidence at present documenting an increased abundance of sea trout around wind turbine foundations (increases in fish abundance tend to be hard bottom dwelling fish species), therefore the above effect of increased prey items attracting sea trout is yet to be recorded. Further, the Proposed Development fish and shellfish ecology study area is situated in an area of high sandeel abundance, and it is likely that sandeel will make up a considerable proportion of sea trout diet when in the marine environment (Svenning et al., 2005; Thorstad et al., 2016). Sandeel species are unlikely to be associated with wind turbine structures due to habitat preferences (discussed in volume 3, appendix 9.1) and therefore sea trout may be less likely to be attracted to increased prey availability colonised on hard substrates, when there is an abundance of prey species which is not associated with the installation of hard substrate.
  4. The low risk of effects on diadromous fish species extends to the freshwater pearl mussel, which is included in the diadromous species section, as part of its life stage is reliant on diadromous fish species including Atlantic salmon and sea trout.
  5. Sea lamprey are parasitic in their marine phase, feeding off larger fish and marine mammals (Hume, 2017). As such it is not expected that they will be particularly attracted to structures associated with offshore wind developments. However, this is not certain, as there is limited information available on the utilisation of the marine environment by sea lamprey.
  6. Most diadromous fish species are deemed to be of low vulnerability, high recoverability and national to international importance. The sensitivity of the receptor is therefore, considered to be low.
  7. Atlantic salmon and sea lamprey are deemed to be of low vulnerability, high recoverability and national to international importance. The sensitivity of the receptor is therefore, considered to be low.
  8. Sea trout are deemed to be of medium vulnerability, high recoverability and national to international importance. The sensitivity of the receptor is therefore, considered to be low.
Significance of the Effect

Marine Species

  1. Overall for IEF species, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms. This is likely to be a conservative prediction as there is some evidence (although with uncertainties) that some fish and shellfish populations are likely to benefit from introduction of hard substrates.

Diadromous Species

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
Secondary Mitigation and Residual Effect
  1. No additional fish and shellfish ecology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

Decommissioning Phase

Magnitude of Impact
  1. During the decommissioning phase, some infrastructure is assumed to be left in situ within the Proposed Development fish and shellfish ecology study area with the impact of colonisation of infrastructure continuing in perpetuity following decommissioning. The maximum design scenario assumes that up to 7,493,186 m2 of scour and cable protection will remain post decommissioning with all foundation structures removed during decommissioning (see Table 9.15   Open ▸ ). This equates to a small proportion (0.6%) of the Proposed Development fish and shellfish ecology study area.
  2. The impact is predicted to be of local spatial extent, permanent duration, continuous and not reversible. It is predicted that the impact will affect fish and shellfish receptors directly. The magnitude is therefore considered to be low.
Sensitivity of the Receptor
  1. The sensitivity of all fish and shellfish IEFs, for both marine and diadromous species, can be found in the construction and operation and maintenance phase assessment above (paragraph 271 et seq.) and are concluded to be low.

 

Significance of the effect

Marine Species

  1. Overall for IEF species, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.

Diadromous Species

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
Secondary Mitigation and Residual Effect
  1. No additional fish and shellfish ecology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

9.11.1.              Proposed Monitoring

  1. This section outlines the proposed monitoring proposed for fish and shellfish ecology. Proposed monitoring measures are outlined in Table 9.30   Open ▸ .

 

Table 9.30:
Monitoring Commitments for Fish and Shellfish Ecology

Table 9.30: Monitoring Commitments for Fish and Shellfish Ecology

 

9.12. Cumulative Effects Assessment

9.12.1.              Methodology

  1. The CEA assesses the impact associated with the Proposed Development together with other relevant plans, projects and activities. Cumulative effects are therefore the combined effect of the Proposed Development in combination with the effects from a number of different projects, on the same receptor or resource. Please see volume 1, chapter 6 for detail on CEA methodology.
  2. The projects and plans selected as relevant to the CEA presented within this chapter are based upon the results of a screening exercise (see volume 3, appendix 6.4 of the Offshore EIA Report). Volume 3, appendix 6.4 further provides information regarding how information pertaining to other plans and projects is gained and applied to the assessment. Each project or plan has been considered on a case by case basis for screening in or out of this chapter's assessment based upon data confidence, effect-receptor pathways and the spatial/temporal scales involved.
  3. In undertaking the CEA for the Proposed Development, it is important to bear in mind that other projects and plans under consideration will have differing potential for proceeding to an operation stage and hence a differing potential to ultimately contribute to a cumulative impact alongside the Proposed Development. Therefore, a tiered approach has be adopted. This provides a framework for placing relative weight upon the potential for each project/plan to be included in the CEA to ultimately be realised, based upon the project/plan’s current stage of maturity and certainty in the projects’ parameters. The tiered approach which will be utilised within the Proposed Development CEA employs the following tiers:
  • tier 1 assessment – Proposed Development (Berwick Bank Wind Farm offshore) with Berwick Bank Wind Farm onshore;
  • tier 2 assessment – All plans/projects assessed under Tier 1, plus projects which became operational since baseline characterisation, those under construction, those with consent and submitted but not yet determined;
  • tier 3 assessment – All plans/projects assessed under Tier 2, plus those projects with a Scoping Report; and
  • tier 4 assessment – All plans/projects assessed under Tier 3, which are reasonably foreseeable, plus those projects likely to come forward where an Agreement for Lease (AfL) has been granted.
    1. The specific projects scoped into the CEA for fish and shellfish ecology, are outlined in Table 9.31   Open ▸ .
    2. Due to the uncertainty regarding assessment of projects in the far future including when projects may be decommissioned and what activities this might involve it has been assumed that the magnitude of impact from decommissioning is likely to be similar or substantially less than those experienced for the construction phase. As a result, no cumulative assessments of decommissioning phases have been undertaken.
    3. As described in volume 1, chapter 3, the Applicant is developing an additional export cable grid connection to Blyth, Northumberland (the Cambois connection). Necessary consents (including marine licences) will be applied for separately. The CEA for the Cambois connection is based on information presented in the Cambois connection Scoping Report (SSER, 2022e), submitted in October 2022. The Cambois connection has been scoped into the CEA for fish and shellfish ecology on the basis that Cambois connection will overlap spatially and temporally with the Proposed Development and the project will engage in activities such as cable burial and installation of cable protection which will impact fish and shellfish IEFs.
    4. The range of potential cumulative impacts that are identified and included in Table 9.32   Open ▸ , is a subset of those considered for the Proposed Development alone assessment. This is because some of the likely significant effects identified and assessed for the Proposed Development alone, are localised and temporary in nature. It is considered therefore, that these potential impacts have limited or no potential to interact with similar changes associated with other plans or projects. These have therefore been scoped out of the cumulative effects assessment.
    5. Similarly, some of the potential impacts considered within the Proposed Development alone assessment are specific to a particular phase of development (e.g. construction, operation and maintenance or decommissioning). Where the potential for cumulative effects with other plans or projects only have potential to occur where there is spatial or temporal overlap with the Proposed Development during certain phases of development, impacts associated with a certain phase may be omitted from further consideration where no plans or projects have been identified that have the potential for cumulative effects during this period.
    6. For the purposes of the fish and shellfish ecology assessment of effects, cumulative effects have been assessed within a representative 25 km buffer of the Proposed Development fish and shellfish ecology study area which encompasses the areas within two tidal excursions ( Figure 9.11   Open ▸ ). This buffer, which is based on two tidal excursions from the Proposed Development fish and shellfish ecology study area, is considered appropriate as the majority of impacts considered in section 9.11 will be localised in extent and this encompasses all projects in the Forth and Tay region. This approach aligns with that taken for Benthic Subtidal and Intertidal Ecology (volume 2, chapter 8) and Physical Processes (volume 2, chapter 7). The only exception to this is underwater noise during the construction phase, where a larger buffer of 100 km has been used to account for the larger ZoI of this impact (i.e. behavioural effects to ranges of tens of km from the Proposed Development fish and shellfish ecology study area).
    7. All impacts that have been identified as having potential cumulative effects have been assessed at the appropriate phases of development in the following sections. Cumulative impacts of increased SSC and associated deposition for the operation and maintenance phase (for both the Proposed Development and cumulative projects) have been excluded from the cumulative assessment. This is due to operation and maintenance activities being of much lower magnitude than construction impacts, being limited to reburial/repair of cables, rather than installation of hundreds of km of cable. Further, there is a relatively low likelihood of cumulative projects operation and maintenance activities occurring at the same time however, there is minimal spatial overlap between projects and due to the relative local scale of SSC impacts it is unlikely that in the event of concurrent maintenance activities, SSC plumes would interact causing a cumulative effect.

 

Table 9.31:
List of Other Developments Considered Within the CEA for Fish and Shellfish Ecology

Table 9.31: List of Other Developments Considered Within the CEA for Fish and Shellfish Ecology

 

Figure 9.11:
Other Projects/Plans Screened into the Cumulative Effects Assessment for Fish and Shellfish Ecology

Figure 9.11: Other Projects/Plans Screened into the Cumulative Effects Assessment for Fish and Shellfish Ecology

9.12.2.              Maximum Design Scenario

  1. The maximum design scenarios identified in Table 9.32   Open ▸ have been selected as those having the potential to result in the greatest effect on an identified IEF or receptor group. The cumulative effects presented and assessed in this section have been selected from the details provided in volume 1, chapter 3 of the Offshore EIA Report as well as the information available on other projects and plans (see volume 3, appendix 6.4), to inform a ‘maximum design scenario’. Effects of greater adverse significance are not predicted to arise should any other development scenario, based on details within the PDE (e.g. different wind turbine layout), to that assessed here, be taken forward in the final design scheme.
Table 9.32:
Maximum Design Scenario Considered for Each Impact as Part of the Assessment of Likely Significant Cumulative Effects on Fish and Shellfish Ecology

Table 9.32: Maximum Design Scenario Considered for Each Impact as Part of the Assessment of Likely Significant Cumulative Effects on Fish and Shellfish Ecology

 

9.12.3.              Cumulative Effects Assessment

  1. An assessment of the likely significance of the cumulative effects of the Proposed Development upon fish and shellfish ecology IEFs arising from each identified impact is given below.

Cumulative Temporary subtidal Habitat Loss/Disturbance

Tier 2

Construction phase

Magnitude of impact

  1. The construction and operation and maintenance of the projects/plans/activities shown in Table 9.32   Open ▸ may lead to cumulative temporary subtidal habitat loss/disturbance within the fish and shellfish ecology CEA study area. Table 9.33   Open ▸ presents the areas of habitat loss for each project. This total area is highly conservative as the majority of the disturbance would not occur at the same time, rather small proportions of habitat loss would occur across the CEA study area over the construction phase for the Proposed Development.
  2. Table 9.32   Open ▸ and Figure 9.11   Open ▸ shows all projects/plans/activities considered in the Tier 2 assessment which are Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable Corridor, Eastern Link 1, Eastern Link 2 and Eyemouth disposal site. There is small overlap between construction phase for the Proposed Development and Inch Cape Offshore Wind Farm and Seagreen 1A Project as well as the operation and maintenance phases once construction has completed. The remaining projects will be in their operation and maintenance phase during the Proposed Development construction phase. The total cumulative temporary subtidal habitat loss is 145,325,450 m2, however this number is highly conservative as habitat loss associated operation and maintenance will be spread over the entirety of the phase, and therefore there will only be a small proportion of this habitat loss happening at any one time.
  3. Table 9.33   Open ▸ shows the cumulative temporary habitat loss/disturbance within a 25 km buffer for all projects in the Tier 2 assessment, noting that the Seagreen 1A assessment does not provide estimates for temporary habitat loss/disturbance associated with operation and maintenance (Seagreen Wind Energy, 2012). The values for temporary habitat disturbance/loss during the construction of the Seagreen 1A Project are presented in Table 9.33   Open ▸ and have been produced by undertaking a separate assessment to determine the maximum design scenario for this project using the following publicly available datasets (Seagreen Wind Energy, 2012b[6]; Seagreen Wind Energy, 2022[7]; and Seagreen Wind Energy 2020[8]). These values have then been subtracted from those provided in the Seagreen 1 assessment (Seagreen Wind Energy, 2012a) to calculate the maximum design scenario for Seagreen 1, to prevent double counting and to ensure these projects are assessed separately and proportionately.
  4. There is also expected to be temporary habitat disturbance from the construction and operation and maintenance of Eastern Link 1 and 2. The environmental appraisal for Eastern Link 1 does not give a specific value for temporary habitat loss in the project however it is expected to include a pre-installation footprint of 50 m and a 30 m footprint for cable installation. Additionally, only 24% of the 176 km Eastern Link 1 cable will be within the Proposed Development fish and shellfish ecology study area therefore only a proportion of the overall impact will be cumulative. Table 9.33   Open ▸ shows that in the construction phase Eastern Link 2 will result in 15,200,000 m2 of temporary habitat disturbance however only 18% of the 436 km cables will occur with the Proposed Development fish and shellfish ecology study area.
  5. There is potential for cumulative impacts to arise with disposal activities at the Eyemouth disposal site. The total area of the site is 664,761 m2 (see Table 9.33   Open ▸ ), however only a very small portion of this would be affected at any one time by an individual disposal event.
  6. The maximum design scenario for habitat loss from the cumulative offshore wind farms, and the Eyemouth disposal site has been considered in this cumulative assessment. However, as noted above, this is considered to be highly precautionary as activities associated with the operation and maintenance phase of wind farms occur intermittently throughout the phase and therefore are unlikely to completely overlap with the construction phase of the Proposed Development.
  7. The cumulative impact is predicted to be of regional spatial extent, short term duration, intermittent and high reversibility. It is predicted that the impact will affect the fish and shellfish IEFs directly. Given the minor temporal overlap in construction activities and that the operation and maintenance activities associated with the relevant projects will not add substantially to the total footprint associated with the Proposed Development and with only a proportion of the operation and maintenance operations occurring during the construction phase of the Proposed Development or overlapping during the operation and maintenance operations, the magnitude of the impact will not be greater than that assumed for the project alone. The magnitude is therefore, considered to be low.

 

Table 9.33:
Total Area and Component Parts of Temporary Habitat Loss/Disturbance of the Relevant Cumulative Impact Projects in the Construction Phase of the Proposed Development

Table 9.33:  Total Area and Component Parts of Temporary Habitat Loss/Disturbance of the Relevant Cumulative Impact Projects in the Construction Phase of the Proposed Development

 

Sensitivity of receptor

  1. The sensitivity of fish and shellfish IEFs is summarised below, and is as described in section 9.11, paragraphs 70 to 89.

Marine Species

  1. Most fish and shellfish ecology IEFs in the Proposed Development fish and shellfish ecology study area and wider Proposed Development northern North Sea fish and shellfish ecology study area are deemed to be of low vulnerability, high recoverability and local to national importance. The sensitivity of the receptor is therefore, considered to be low.
  2. European lobster and Nephrops are deemed to be of high vulnerability, medium to high recoverability and of regional importance. The sensitivity of these fish and shellfish receptors is therefore considered to be medium.
  3. Herring are deemed to be of high vulnerability, medium recoverability and of regional importance. However, the sensitivity of herring to this impact is considered to be low, due to the limited suitable spawning sediments overlapping with the Proposed Development fish and shellfish ecology study area and the core herring spawning ground being located well outside the Proposed Development fish and shellfish ecology study area.
  4. Sandeel are deemed to be of high vulnerability, high recoverability and of national importance. The sensitivity of sandeel is therefore considered to be medium.

Diadromous Species

  1. Diadromous fish species are deemed to be of low vulnerability, high recoverability and national to international importance. The sensitivity of the receptor is therefore, considered to be low.

Significance of effect

Marine Species

  1. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of most fish and shellfish IEFs (including herring) is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
  2. For sandeel, the magnitude of the cumulative effect is deemed to be low and the sensitivity is considered to be medium. Given the minor temporal overlap in construction activities and the operation and maintenance activities associated with the relevant projects, these will not add substantially to the total footprint associated with the Proposed Development. With only a small proportion of the operation and maintenance operations occurring during the construction phase of the Proposed Development and spread over a much larger area than the Proposed Development alone, the significance of the effect will not be greater than that assumed for the project alone. The effect will, therefore, be of minor adverse significance which is not significant in EIA terms.
  3. For Nephrops and European lobster, the magnitude of the cumulative impact is deemed to be low and the sensitivity is considered to be medium. However, the significance of effect will not be greater than that assumed for the Proposed Development alone for the reasons outlined above.

Diadromous Species

  1. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of the receptor is considered to be low. The cumulative effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

  1. No additional fish and shellfish ecology mitigation is considered necessary as the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.