2014 Consultation on the Management of Inshore Special Areas of Conservation and Marine Protected Areas Approaches.

Protected Area K - Small Isles MPA

Introduction

This section sets out 2 possible management approaches for this protected area. Under both of these approaches further measures will be required for northern seafan and sponge communities, black guillemot, and possibly burrowed mud.

Approach 2 is preferred because it would minimise the buffer area around the mosaic of habitats in the Sound of Canna.

A description of this protected area can be found in the main consultation document is Annex A, Protected Area K.

Maps to support understanding of the approaches can be found under Protected Area K in the technical maps document. Figure K1 shows Small Isles in context with other protected areas. Figure K2 shows the distribution of the protected features

Measures for Small Isles would be delivered by Statutory Instrument using powers under the Inshore Fishing (Scotland) Act 1984.

Questions 25 to 27 refer to Small Isles.

The site features and conservation objectives

Protected Feature	Conservation objective
Fan mussel aggregations	Conserve
Horse mussel beds	Conserve
Black guillemot	Conserve
Burrowed mud	Conserve
Circalittoral sand and mud communities	Conserve
northern seafan and sponge communities	Conserve
Northern featherstar aggregations	Conserve
White cluster anemone	Conserve

Summary of the management advice

Feature	Mobile Gear	Static Gear	Other gear
Fan mussel aggregations and horse mussel beds	Remove / avoid pressure from demersal trawl, mechanical dredges, or suction dredges.	Consider reduce / limit pressure
Burrowed mud	Consider reduce / limit pressure from demersal trawl, mechanical dredges, or suction dredges especially where there are aggregations of tall sea pens or other epibenthic species	Consider reduce / limit pressure where there are aggregations of tall sea pens or other epibenthic species
Circalittoral sand and course sediment communities	No specific recommendation (likely to be delivered by burrowed mud management)	No advice
Black guillemot	No management required	Remove / avoid pressure from set nets
Northern featherstars aggregations on mixed substrata	Consider reduce / limit pressure from demersal trawl, mechanical dredges, or suction dredges.	No management required
Northern seafan and sponge communities	Remove / avoid pressure from demersal trawl, mechanical dredges, or suction dredges.	Consider reduce / limit pressure
White cluster anemones	Management put in place for the northern sea fan and sponge communities would ensure protection of this feature.	Consider reduce / limit pressure

Fan mussels are highly sensitive to mobile demersal gear as they can have a significant proportion of their shell projecting above the sediment surface making them particularly vulnerable to towed gear, which can cause damage to the shell. In addition, they cannot survive being uprooted from the seabed. There is no published information relating to interactions between fan mussels and static gears but there is the potential for pots or nets to cause disturbance either via direct impact during deployment or recovery of gear, or entanglement.

Horse mussel beds are highly sensitive to the physical impacts associated with mobile demersal gear which can cause direct mortality from shell damage, by breaking up the bed and by affecting or removing associated fauna attached to the bed. Horse mussel beds are also sensitive to the indirect effects of increased sedimentation, which can result in smothering and can result in the subsequent mortality of individuals. Whilst the sensitivity to static gears is lower than for mobile gears, depending on the type of epifauna present on the horse mussel beds this may increase if fishing intensity is high.

Northern feather star aggregations and northern seafan and sponge communities have medium sensitivity to pressures associated with demersal mobile gear e.g. surface abrasion and removal of species. The potential effects on northern feather star aggregations are through direct mortality through capture or contact with gear and possible indirect effects from smothering and/or increased suspended sediment. The degree of effects will depend on the gear type, substrate composition and local hydrodynamic conditions.

Northern seafan and sponge communities are at most risk where rocks or boulders which they grow on are of low relief and these areas may be fishable ( e.g. with rockhopper gear). Where mobile demersal fishing gears come into contact with these communities the slower growing fragile fauna such as sponges and sea fans are liable to suffer high mortality from direct impact and from disturbance of their substrate ( e.g. overturning of boulders). For static gear whilst there is potential for abrasion on fauna when being deployed or recovered, this impact may be limited and will be dependent on intensity of fishing.

Burrowed mud has medium sensitivity to physical pressures associated with mobile demersal fishing gear e.g. surface and sub-surface abrasion. Physical disturbance of the surface of the seabed is likely to affect mobile and sessile epifaunal and shallow burrowers, for example damage to seapen species is likely to take place as a result of greater sediment disturbance from towed demersal gear.

Trawling for Nephrops can, by reducing the number and size of burrowing individuals present, also affect the habitat structure itself in terms of the number and size of burrows present. However the degree of impact in terms of diversity and relative abundance of species is likely to be related to the intensity of fishing activity, and there is scope for recovery. For static gear, it is likely that when fishing activity is low, direct impacts on the habitat is likely to be minimal and seabed structure is likely to be maintained in a slightly modified state. However the impacts of increasing static gear fishing intensity and the subsequent impacts on the habitat are less well understood.

There is a potential risk of bycatch / entanglement of black guillemot in fishing nets, set nets in Scotland pose the potential biggest risk and therefore management advice has been given relating to this gear type.

The approaches to management

Static gear assessment

Static gear activity is moderate in Sound of Canna according to Scotmap. The current levels are not considered to be impacting on the habitats. Consequently no static gear management is proposed. However if future studies found there to be a negative effect then this would be addressed then.

Measures common to both approaches

The use of suction dredges (boat or diver operated) would be prohibited throughout the MPA. The size of vessel which can fish in the MPA would be restricted to 150 Gross Registered Tonnage ( GRT).

Approach 1

The proposed measures

In addition to the common measures demersal trawling and mechanical dredging would be prohibited in the area shown in blue in figure K3.

The benefit

The new measures would remove / avoid pressure from fishing methods that could have an impact on the fan mussel aggregation and the horse mussel bed, as well as for the northern sea fan and sponge communities and the white cluster anemone. This would ensure that from a fisheries perspective the conservation objective for these habitats would be furthered and the only known example of a fan mussel aggregation conserved. It would also contribute to reducing/limiting pressure for the northern feather star aggregations.

The extended area to the north of Sound of Canna would bring considerable amounts of burrowed mud and the circalittoral sand and coarse sediment into the prohibited area. This means that less management would be required in the 2 ^nd batch of measures for these habitats.

The capacity restriction and prohibition on hydraulic and suction dredging would put a limit on pressure on the benthic habitats.

The costs

For over 15m vessels which have VMS the following data can be derived using a dataset from 2007 to 2013.

Method	Average annual MPA value	Average annual value affected	% of value affected	Average annual effort hours in MPA	Average annual effort hours affected	% of effort affected
Trawl	£619	£75	12%	8113	913	11%
Dredge	£58	£10.5	18%	719	114	16%

Table K1: Average annual impact of approach 1 based on 2007 to 2013 data for over 15 metre vessels (rounded to nearest £000s)

Small Isles covers part of ICES rectangles 42E3 and 43E3. According to the analysis of Scotmap data for trawl and dredge fisheries approximately 20% of the total value of those ICES Rectangles is taken from the MPA. Amount affected is based upon the effort proportion affected for trawling by over 15 metre vessels.

Method	Total effort days	Effort days affected	Total value	Value effected
Trawl / Dredge	372	41	£417	£46

Table K2: Average annual impact of approach 1 based on 2013 data for under 15 metre vessels (rounded to nearest £000s)

The displacement effects

The area to the north and South of the Sound of Canna are important fishing grounds. Not being able to fish here will intensify fishing on the rest of the burrowed mud habitat within the MPA. The intensity is fairly evenly spread across the habitat as can be seen in figure K6. This would likely have a greater impact on smaller vessels who work nearer the islands on a more frequent basis. The main scallop grounds have mainly been avoided as can be seen in figure K5.

Approach 2 (preferred approach)

The proposed measures

In addition to the common measures demersal trawling and mechanical dredging would be prohibited in the area shown in yellow in figure K4.

The benefit

The new measures would remove / avoid pressure from fishing methods that could have an impact on the fan mussel aggregation and the horse mussel bed, as well as for the northern sea fan and sponge communities and the white cluster anemone. This would ensure that from a fisheries perspective the conservation objective for these habitats would be furthered and the only known example of a fan mussel aggregation conserved. It would also contribute to reducing/limiting pressure for the northern feather star aggregations.

The capacity restriction and prohibition on hydraulic and suction dredging would put a limit on pressure on the benthic habitats.

The costs

For over 15m vessels which have VMS the following data can be derived using a dataset from 2007 to 2013.

Method	Average annual MPA value	Average annual value affected	% of value affected	Average annual effort hours in MPA	Average annual effort hours affected	% of effort affected
Trawl	£619	£42	7%	8113	527	6.5%
Dredge	£58	£7	12%	719	77	11%

Table K3: Average annual impact of approach 2 based on 2007 to 2013 data for over 15 metre vessels (rounded to nearest £000s)

Small Isles covers part of ICES rectangles 42E3 and 43E3. According to the analysis of Scotmap data for trawl and dredge fisheries approximately 20% of the total value of those ICES Rectangles is taken from the MPA. Amount affected is based upon the effort proportion affected for trawling by over 15 metre vessels.

Method	Total effort days	Effort days affected	Total value	Value effected
Trawl / Dredge	372	24	£417	£27

Table K4: Average annual impact of approach 2 based on 2013 data for under 15 metre vessels (rounded to nearest £000s)

The displacement effects

The area to the north and south of the Sound of Canna are important fishing grounds. Not being able to fish here will intensify fishing on the rest of the burrowed mud habitat within the MPA, so by keeping the inclusion of nephrops trawl grounds as low as possible will minimise displacement.