Draft Fisheries Assessment – North West Rockall Bank SAC: Fisheries management measures within Scottish Offshore Marine Protected Areas (MPAs)

3. Part B Assessment – Fisheries Assessment

3.1 Fishing assessment overview

Part B of this assessment meets the requirements for an appropriate assessment under Article 6(3) of Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora (the Habitats Directive) and Regulation 28 of the Conservation of Offshore Marine Habitats and Species Regulations 2017.

The fishing activities and pressures identified in Part A, at the levels identified in the relevant date range, which have been included for assessment in Part B, are demersal trawls, demersal seines, and anchored nets/lines. The only pressures associated with these fishing activities that have been included in Part B are:

• abrasion/disturbance of the substrate on the surface of the seabed;
• penetration and/or disturbance of the substrate below the surface of the seabed, including abrasion;
• smothering and siltation rate changes (light);
• removal of non-target species and
• removal of target species.

3.2 Fishing Activity Descriptions

3.2.1 Existing management of fishing activity within North West Rockall Bank SAC

Under The Common Fisheries Policy and Animals (Amendment etc.) (EU Exit) Regulations 2019 Statutory Instrument 2019, No. 1312, Annex XII, Part D, it is prohibited to conduct bottom trawling and fishing with static gear (including bottom set gillnets and bottom set longlines) within the North-West Rockall area, for the protection of sensitive habitats. The use of creels and static hook gear is also restricted in the area.

3.2.2 Fishing activity within North West Rockall Bank SAC

The Northwest Rockall Bank SAC overlaps ICES rectangles 42D5, 43D5, 44D5, 44D6, 45D5 and 45D6 in Rockall (ICES Division 6b), in the Rockall region. The main gear types for UK vessels are demersal trawls and set nets, predominantly catching haddock and monk/anglerfish.

VMS-based estimates and ICES rectangle landings statistics indicate that over-12m demersal trawls and set nets are the predominant UK vessels that operated within the site over the period 2015-2019.

For the over-12m vessels, based on VMS data from 2015-2019, demersal trawls operate predominantly along the north-western and north-eastern site boundaries. Set nets are scattered throughout, although there is a small concentration of activity recorded along the upper eastern boundary.

In addition to UK activity, vessels from Ireland (21 vessels), Norway (7 vessels), Germany, Faroes and Spain (number of vessels cannot be disclosed) may also operate in the site, based on VMS data from 2015-2019. However, it is not clear what gear types these vessels operate, nor whether they were actively fishing at the time.

3.2.3 Demersal trawls

The aggregated gear method of demersal trawls includes multiple gears that operated within North West Rockall Bank SAC between 2015 and 2019. These include bottom otter trawls, multi-rig trawls, pair trawls, and other not specified bottom trawl types (Table 1). The target species for these gear types are demersal fish and molluscs. Similar pressures are exerted by the different gears used for demersal trawling, subsequently the aggregated gear type of ‘demersal trawl’ was used to map activity across the site.

According to VMS intensity averaged over 2015 to 2019, the distribution of demersal trawling broadly occurs along the boundaries of the site (Figure 2). Demersal trawling is concentrated in the north of the site, along the southern boundary (48 - 168 fishing hours per year per grid cell). The remainder of the site either has no activity, or less than 12 hours of activity per year per grid cell, such as in the central area of the west side of the site.

Swept-Area Ratio (SAR) information averaged over the same time period shows similar pattern of fishing intensity as the VMS data (Figure 2). The highest SAR values are in the eastern area of the site, along the southern boundary (cells swept 2 – 5 or 1 – 2 times per year per grid cell). The remainder of the site either has no activity, or cells being swept less than once.

3.2.4 Demersal seines

Only one demersal seine gear type operated within the North West Rockall Bank SAC between 2015 and 2019 (Table 1), which was anchor seines. The target species for this gear type is demersal fish.

According to VMS intensity averaged over 2015 to 2019, demersal seines activity only occurred in the south-west corner of the site, where less than 12 hours of activity occurred per year per grid cell (Figure 3). No activity occurred in the remainder of the site.

Swept-Area Ratio (SAR) information averaged over the same time period shows similar patterns of fishing intensity as the VMS data (Figure 3). The only activity was in the south-west corner of the site, with cells swept less than once per year per grid cell. No activity occurred in the remainder of the site.

3.2.5 Anchored nets/lines

Only one anchored nets/lines gear type operated within the North West Rockall Bank SAC between 2015 and 2019 (Table 1), which was set gillnets. The target species for this gear type is demersal fish.

According to VMS intensity averaged over 2015 to 2019, anchored nets/line activity is distributed throughout the site, yet only occurs at fairly low levels with less than 12 hours of activity per year per grid cell (Figure 4). Only one small area had slightly higher activity of 12-24 hours per year per grid cell on the eastern boundary of the site.

3.2.6 Summary of fishing activity within North West Rockall Bank SAC

The most common fishing activity within the North West Rockall Bank SAC is demersal trawling, however this is mainly concentrated along the boundaries of the site, so only small areas of the site experience moderate levels of this activity (the majority of the site has little to no activity). Demersal seines are more restricted in their distribution and only occurs at very low levels in a small area in the south-west corner of the site. Anchored nets/lines activity is distributed throughout the site, but also only occurs at very low levels. The Annex I Reef feature occurs throughout the entire SAC, so it is likely that there is overlap between these fishing activities and the protected feature.

3.3 Fishing activity effects overview

The following sections explore the pressures associated with fishing activity (demersal trawls, demersal seines and anchored nets/lines) within the East Rockall Bank SAC that were identified as potentially having likely significant effects (LSE) on the reef feature. The pressures considered in the following sections are:

• Abrasion/disturbance of the substrate on the seabed;
• Penetration and/or disturbance of the substrate below the surface of the seabed, including abrasion;
• Smothering and siltation rate changes (light);
• Removal of target species; and
• Removal of non-target species.

All five pressures, as exerted by mobile demersal fishing (trawls and seines), were considered to have the potential for LSE. For static demersal fishing (anchored nets/lines), only abrasion/disturbance of the substrate on the surface of the seabed, removal of target species, and removal of non-target species were considered to have the potential for LSE.

Given the similarity between ‘abrasion/disturbance of the substrate on the surface of the seabed’ and ‘penetration and/or disturbance of the substrate below the surface of the seabed’, these two pressures are considered together in the text below. All pressures with the potential for LSE are discussed under the aggregated fishing gear types of ‘mobile demersal gears’ and ‘static demersal gear’.

The detailed pressure information for this section is based on the JNCC Advice on Operations for North West Rockall Bank SAC. In the absence of a JNCC Fisheries Management Options Paper for this site, the Site Proposal document within the consultation package cab be used to provide additional information.

3.3.1 Summary of impacts associated with demersal mobile gear (trawls and seines) on Annex I Reef

As detailed in the JNCC Advice on Operations for North West Rockall Bank SAC, abrasion/disturbance of the substrate on the surface of the seabed and penetration and/or disturbance of the substrate below the surface of the seabed, including abrasion, occur where gear makes contact with the seafloor. The area affected is determined by the footprint of the gear and the amount of movement across the seabed. The different gear components will make variable contributions to the total physical disturbance of the seabed and its associated biota, and hence the pressure will vary according to factors such as gear type, design/modifications, size and weight, method of operation (including towing speed) and habitat characteristics (e.g. topography) (Lart, 2012; Polet & Depestele, 2010; Suuronen et al., 2012). Towed bottom fishing gears are used to catch species that live in, on or in association with the seabed and therefore are designed to remain in close contact with the seabed. That interaction with the seabed can lead to disturbance of the upper layers of the seabed, direct removal, damage, displacement or death of the benthic flora and fauna; short-term attraction of scavengers; and the alteration of habitat structure (Kaiser et al., 2003; Gubbay & Knapman, 1999; Sewell & Hiscock, 2005; Collie et al., 2000; Kaiser et al., 2002).

Benthic seines are generally of lighter construction as there are no trawl doors or warps, resulting in less disturbance of the seabed than trawling (Polet & Depestele, 2010; Donaldson et al., 2010; Suuronen et al., 2012). As a relative comparison of gear types, otter trawls tend to have less physical impact on the seafloor than beam trawls (and dredges) with the heavy tickler chains of beam trawls able to penetrate up to 8 cm into the seabed, although the doors of an otter trawl do create recognisable scour of the seabed (Hinz et al., 2012; Polet & Depestele, 2010; Lart, 2012; Paschen et al. 2000). The magnitude of the immediate response to fishing disturbance, cumulative effects and recovery times varies significantly according to factors such as the type of fishing gear and fishing intensity, the habitat and sediment type, and levels of natural disturbance and among different taxa (Collie et al., 2000; Boulcott et al., 2014; Kaiser et al., 2006; Hinz et al., 2009; Kaiser et al., 2001).

Smothering and siltation rate changes (light) may result from physical disturbance of the sediment, along with hydrodynamic action caused by the passage of towed gear, leading to entrainment and suspension of the substrate behind and around the gear components and subsequent siltation (Gubbay & Knapman, 1999; Lart, 2012; Sewell et al., 2007; Kaiser et al., 2002; Riemann & Hoffmann, 1991; O'Neill et al., 2008; Dale et al., 2011; O'Neil & Summerbell, 2011). The quantity of suspended material, its spatial and temporal persistence and subsequent patterns of deposition will depend on factors associated with the gear (such as type/design, weight, towing speed), sediment (particle size, composition, compactness), the intensity of the activity and the background hydrographic conditions (Sewell et al., 2007; Kaiser et al., 2002; Dale et al., 2011; O'Neil & Summerbell, 2011). Sediment remobilisation and deposition can affect the settlement, feeding, and survival of biota through smothering of feeding and respiratory organs. Prolonged exposure of an area to the pressure may result in changes in sediment composition (Gubbay & Knapman, 1999; Kaiser et al., 2002; O'Neil & Summerbell, 2011; Kaiser et al., 2003; Sewell et al., 2007).

The Annex I reef feature is not a target of any fishing activity occurring within the SAC. Demersal trawls target a range of demersal fish species and may also remove non-target species which may themselves be of conservation importance or may form part of the biotope (e.g. Norway lobster - Nephrops norvegicus) or wider community composition associated with protected features/sub-features. As part of demersal trawl activity, incidental non target catch may also be retained and landed due to its commercial value (e.g. spiny lobster (Palinurus elephas), lobsters (Homarus gammarus), crabs, scallops (Pecten spp.), etc). These species may be considered part of the wider community composition associated with features or sub-features of designated sites or may themselves be of conservation importance (e.g. crawfish) (Sewell & Hiscock 2005; JNCC & NE 2011).

Bycatch (i.e. discarded catch) is associated with almost all fishing activities and is related to factors such as gear type and its design (i.e. its selectivity), the target species and effort. There are significant concerns over the impacts of discards on marine ecosystems including changes in population abundance and demographics of affected species and altered species assemblages and food web structures (Alverson et al., 1994; Kaiser et al., 2001).

As with other benthic towed gears, discarding of fish species from demersal seine net fisheries can be significant (Polet & Depestele, 2010; ICES, 2011). There are relatively few studies of the non-fish bycatch composition for demersal seines, however, it is probably similar to that of demersal trawls e.g. crustaceans and other invertebrates, etc., although quantities of such bycatch are likely to be lower than that of other gear types such as beam trawls (Suuronen et al., 2012; ICES, 2011; Donaldson et al., 2010; Walsh & Winger, 2011). Mixed-species and shrimp/prawn demersal trawl fisheries are associated with the highest rates of discarding and pose the most complex problems to resolve (Alverson et al., 1994; Feekings et al., 2012; Catchpole et al., 2005). Benthic trawls most frequently result in bycatch of fish crustaceans and other invertebrates and less frequently turtles and birds (Gubbay & Knapman, 1999; Sewell & Hiscock, 2005; ICES, 2013; Pierpoint, 2000; Bergmann & Moore, 2001; Catchpole et al., 2005; Tulp et al., 2005).

Whilst it is unlikely that demersal mobile gears (demersal trawls and demersal seines) can affect the long-term natural distribution of stony reef features, there is evidence to indicate that their use can impact the structure and function of the habitat and the long term survival of its associated species.

The use of demersal mobile fishing gears is likely to cause damage or death of fragile, erect species, such as sponges and corals (Freese et al., 1999; Løkkeborg, 2005). Other species such as hydroids, anemones, bryozoans, tunicates and echinoderms may also be vulnerable (McConnaughey et al., 2000; Sewell & Hiscock, 2005). Where fragile, slow growing species occur, even low levels of fishing have the potential to change the structure and function of the habitats and may result in the loss of some characteristic species.

Demersal mobile gears reduce the long-term natural distribution of cold-water coral (biogenic reef) features, as well as impacting the structure and function of the habitat and the long term survival of its associated species. The passage of demersal mobile fishing gear may increase mortality of the coral by crushing, burying or wounding corals, increasing susceptibility to infection and epifaunal recruitment that may eventually smother corals (Fosså et al., 2002).

The passing of a heavy trawl reduces the three-dimensional structure of the coral to rubble, decreasing the complexity of the habitat with impacts on the associated community composition (Koslow et al., 2001; Fosså et al., 2002). Indirect impacts on cold water coral reefs from trawling are from increased levels of suspended particles in the water column causing smothering and polyp mortality (Larsson & Purser, 2011). Given the slow growth rate of the reefs, they may take centuries to recover from damage, if at all (ICES, 2010).

VMS data shows that demersal trawling is mainly concentrated along the boundaries of the site, where it occurs at moderate levels. Demersal seines are more restricted in their distribution and only occur at very low levels in a small area in the south-west corner of the site. As the Annex I Reef feature occurs throughout the entire SAC, it is likely that there is overlap between these fishing activities and the protected feature.

With regards to the discussion above and the assessed activity levels, the Scottish Ministers conclude that impacts from demersal mobile gear (demersal trawling and demersal seines) on the Annex I Reef feature, particularly the cold-water coral reef (biogenic reef), within North West Rockall Bank SAC are not compatible with the conservation objectives of the site and could result in an adverse effect on site integrity at current levels of activity.

3.3.2 Summary of impacts associated with demersal gear (anchored nets/lines) on Annex I Reef

As detailed in the JNCC Advice on Operations for North West Rockall Bank SAC, abrasion/disturbance of the substrate from the nets/lines themselves and any footropes and anchors. This is most likely to happen during retrieval of the gear if it is dragged along the seabed before ascent, although disturbance of the seabed can occur while the gear is fishing if movement (particularly of any anchors) occurs during rough weather, for example, or otherwise. Such physical disturbance can result in epifauna, especially emergent species such as erect sponges and coral, being dislodged (including being snagged in the net) or damaged, although there are limited studies of such effects (Lart, 2012; Polet & Depestele, 2010; Sewell & Hiscock, 2005; Suuronen et al., 2012; Auster & Langton, 1999).

For removal of target species, anchored nets and lines are used to target pelagic, demersal and benthic fish and crustacean species. Anchored nets and lines can result in the targeted removal of features of conservation importance (e.g. spiny lobster (Palinurus elephas), salmon (Salmo salar)) and also species which form part of the community composition of features or sub-features, e.g. species such as crab and lobster (Homarus gammarus), which may be associated with reef features and other species such as whelks (Gubbay & Knapman, 1999; Sewell & Hiscock, 2005; JNCC & NE, 2011). The Annex I reef feature is not a target of any fishing activity occurring within the SAC.

Bycatch (i.e. discarded catch) is associated with almost all fishing activities and is related to factors such as the gear type and its design (i.e. its selectivity), the targeted species and effort. Anchored nets, including gill and trammel nets, can result in the entanglement and bycatch of a range of fauna including mammals, turtles, fish, elasmobranchs, crustaceans and other invertebrates and birds (Gubbay & Knapman, 1999; ICES, 2013; WWT, 2012; Žydelis et al., 2009; Pierpoint, 2000; Oliver et al., 2015), the consequences of which can be significant to species and populations (Reeves et al., 2013; Furness, 2003; Tasker et al., 2000). Further, ghost fishing has been associated with lost gear (Matsuoka et al., 2005). Although highly selective for the larger pelagic fish, longlines can cause by-catch of large and frequently long-lived species including invertebrates (Hall et al., 2000; Gubbay & Knapman, 1999; Sewell & Hiscock, 2005; Dayton et al., 1995). In the UK, long line fishing is operated on a small scale by only a few inshore vessels in different parts of the country.

Static bottom contacting gears are unlikely to affect the long-term natural distribution of bedrock and stony reef features, but there is evidence to indicate that their use can impact the structure and function of the habitat and the long term survival of its associated species.

Mechanical impacts of demersal static gear (e.g. weights and anchors hitting the seabed, hauling gear over seabed, rubbing/entangling effects of ropes) can damage some species (Eno et al., 1996). Other species appear to be resilient to individual fishing operations but the effects of high fishing intensity are unknown (Eno et al., 2001). Recovery will be slow (Foden et al., 2010) resulting in significant reduction or even loss of characteristic species. The individual impact of a single fishing operation may be slight but cumulative damage may be significant (Eno et al., 2001; Foden et al., 2010).

Demersal static gears are likely to reduce the long-term natural distribution of cold water coral (biogenic reef) features, as well as impacting the structure and function of the habitat and the long term survival of its associated species.

The impacts are considered to be lower than for demersal mobile gear types (Pham et al. 2014), however impacts to habitats and biota may occur during certain conditions. For example, hooks, lines, nets and ropes entangle corals and ‘pluck’ them during hauling (Grehan et al., 2004; ICES, 2010; Sampaio et al. 2012). Physical damage to the seabed has been observed which may be caused by dragged anchors (Grehan et al., 2004; ICES, 2010). The individual impact of a single fishing operation may be slight but cumulative damage can be significant. Given the slow growth rate of the reefs, they may take centuries to recover from damage, if at all (Fosså et al. 2000 & 2002; ICES advice, 2005-2010).

VMS data shows anchored nets/lines activity is distributed throughout the site, but also only occurs at very low levels. As the Annex I Reef feature occurs throughout the entire SAC, however, it is likely that there is overlap between this fishing activity and the protected feature.

With regards to the discussion above and the assessed activity levels, the Scottish Ministers conclude that impacts from anchored nets/lines on the Annex I Reef feature, particularly the cold-water coral reef (biogenic reef), within North West Rockall Bank SAC are not compatible with the conservation objectives of the site and could result in an adverse effect on site integrity at current levels of activity.

3.4 Part B Conclusion

The assessment of fishing pressures at current activity levels on reef features of the North West Rockall bank SAC has indicated that an adverse effect on site integrity cannot be ruled out where mobile demersal fishing (demersal trawl and demersal seine) and anchored nets/line activities occur. As such Scottish Ministers conclude that management measures are required to restrict these activities within North West Rockall Bank SAC. Section 5 contains further details on potential measures.