Draft Fisheries Assessment – Geikie Slide and Hebridean Slope NCMPA: Fisheries management measures within Scottish Offshore Marine Protected Areas (MPAs)

2. Part A assessment – fisheries screening

2.1 Fisheries screening overview

Part A of this assessment considers whether the fishing activity would be capable of impacting the protected features of an MPA or any ecological or geomorphological process on which the conservation of any protected feature is dependent. This section looks at the pressures exerted by the fishing activity occurring in the site (within the assessment period) in relation to the sensitivities of the protected features. Activities potentially capable of impacting the protected features were identified where there was both a medium-high risk of a pressure arising from the fishing activity and if any of the features were considered sensitive to that pressure. These pressure-features interactions were then taken forward to the fisheries assessment stage (Part B) to determine whether the fishing activity in question would or might hinder the achievement of the conservation objectives.

For each activity assessed in Part A, there were two possible outcomes for each identified pressure-feature interaction:

1. The pressure-feature interactions were not included for Part B:

a. If the features is not exposed to the pressure, and is not likely to be in the future; or

b. If the effect/impact of the pressure is non-existent or insignificant.

2. The pressure-feature interactions were included for assessment in Part B:

a. If the feature is exposed to the pressure, or is it likely to be in the future; and

b. If the pressure is capable of impacting the feature; or

c. If it is not possible to determine whether pressure is capable of impacting the feature.

Part B of the assessment considers the potential for activities to impact the feature by assessing the impact of fishing gears identified in Part A. This involves determining the potential level of interaction between the feature and the fishing activity, assessing the potential impact on the feature, and subsequently if fishing activities would or might hinder the achievement of the conservation objectives for the site.

Consideration of exposure to and the effect of a pressure on a protected feature of the MPA includes the consideration of exposure to and the effect of that pressure on any ecological or geomorphological process on which the conservation of the protected feature is wholly or in part dependant.

The JNCC Conservation Advice package and Fisheries Management Options Paper has been used to inform this assessment. This is the most recent assessment package and options paper available.

Where appropriate, this advice has been supplemented by information on pressures associated with fishing activity from the JNCC Marine Pressures-Activities Database (PAD) v1.5 2022 and the Feature Activity Sensitivity Tool (FeAST).

2.2 Activities taking place within Geikie Slide and Hebridean Slope NCMPA

To screen out fishing activities that were not taking place within the site or likely to take part in the future, Vessel Monitoring System (VMS) data within Geikie Slide and Hebridean Slope NCMPA from 2015 – 2019 were analysed to identify the gear types being used in the site and the aggregated gear method (Table 1). The fishing gears screened out at this stage were not taken forward to Part B of the assessment.

Although pelagic trawling occurs within the site, JNCC have provided evidence within the Fisheries Options paper to consider this pelagic trawling and purse seining are not capable of impacting the protected features as this fishing activity does not have contact with the seabed.

2.3 Potential pressures exerted by site fishing activity

According to the JNCC Geikie Slide and Hebridean Slope NCMPA Management Options Paper (2014), the fishing activities considered capable of impacting the burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features are beam trawling, line fishing, otter trawling and set netting.

The potential pressures that could be exerted by fishing activities considered capable of impacting the burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features were determined using information on activity-pressure relationships in the JNCC Marine Pressures-Activities Database (PAD) v1.5 2022. The potential pressures that could be exerted by demersal trawls and anchored nets/lines are summarised in Table 2.

The aggregated gear type of 'anchored nets/lines' spans two categories in the PAD: set (fixed) net fishing and line fishing. Subsequently, potential pressures for this aggregated gear type were listed under the two PAD categories (Table 2). The risk profiling of pressures was the same for set (fixed) net fishing and line fishing within PAD, confirming that these categories could be considered together under the aggregated gear type of 'anchored nets/lines' in later sections of the assessment.

2.4 Significance of effects/impacts to protected features

In the absence of a JNCC Advice on Operations advice package for this site, the Feature Activity Sensitivity Tool (FeAST) was used to determine the potential sensitivity of the Burrowed mud, Offshore deep-sea mud and Offshore subtidal sands and gravels features (Table 3) to the pressures exerted by the relevant fishing activities (Table 2).

Table 3 identifies the pressures from particular gears that could be capable of impacting each feature. Where a pressure from a particular gear is identified as being capable of impacting a feature, justification is provided. To ensure the effects of fishing activities in-combination with other activities (including other fishing activities) are fully assessed, the pressures from fishing activities which were not identified as being capable of impacting a feature, but which do interact with the feature are considered in the in-combination aspect of the assessment (Part C).

*An asterisk is used to denote an underlaying range of sensitivities for habitat features (e.g. due to the feature including species with a range of different sensitivities to a pressure). High* denotes that the highest sensitivity score for the features is high; medium* denotes that the highest sensitivity score for the feature is medium. Unknown is used where there is no information in FeAST about the sensitivity of this habitat to the pressure listed.

Considering both the information on the pressure activity association (Table 2) and the sensitivity of the subtidal sands and gravels feature (Table 3), pressures that have the potential to impact the feature are summarised in Table 4.

Pressures that are not relevant to demersal trawls and anchored nets/lines (pressures that are not exerted by that fishing activity: 'not relevant to the activity' in Table 2) do not need to be considered further in the assessment. According to the PAD methods document (Robson et al., 2018), pressures with low risk profiles (i.e. 'low' risk profile for the activity: Tables 2 & 4) generally do not occur at a level of concern and should not require consideration as part of an assessment, unless there are evidence-based case or site-specific factors that increase the risk, or there is uncertainty on the level of pressure on a receptor. Pressures with 'medium-high' risk profiles are commonly induced by the activity at a level that needs to be considered further as part of an assessment.

Pressures with a medium-high risk profile in PAD and to which FeAST assessed the feature as being Sensitive, Medium Sensitivity or High Sensitivity have the potential to impact the feature.

Of all the pressures considered, six have medium-high risk profiles (PAD) and have medium-high sensitivity (FeAST): 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; changes in suspended solids (water clarity); smothering and siltation rate changes (light); removal of target species; and removal of non-target species (Table 4). These six pressures are subsequently considered to have the potential to impact the burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features. All six of these pressures are exerted by demersal trawls. Of these pressures exerted by anchored nets/lines only three pressures; abrasion/disturbance of the substrate on the surface of the seabed; removal of target species and removal of non-target species (Table 4) are considered to have the potential to impact the burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features.

To ensure the effects of fishing activities in-combination with other activities (including other fishing activities) are fully assessed, the pressures from fishing activities which were not identified as capable of impacting the feature but which do interact with the features are considered in the in-combination aspect of the assessment (Part C).

2.5 Part A Conclusion

Considering the information on pressures and sensitivity above, demersal mobile fishing (trawls) has the potential to impact burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features within Geikie Slide and the Hebridean Slope MPA, through penetration and/or disturbance of the substrate below the surface of the seabed, including abrasion; smothering and siltation rate changes (light); changes in suspended solids (water clarity); removal of target species; and removal of non-target species.

Static demersal fishing (anchored nets/lines, specifically longlining) has the potential to impact burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features within Geikie Slide and the Hebridean Slope MPA, through abrasion/disturbance of the substrate on the surface of the seabed; removal of target species; and removal of non-target species.

The six pressures are considered to have the potential to impact the burrowed mud, offshore deep-sea mud and offshore subtidal sands and gravels features are taken through to Part B of the assessment.