CENTRAL FLADEN POTENTIAL AREA FOR AN MPA
Site characteristics
Description - The potential area lies within the large expanse of muddy sand and sandy mud
sediment plain of the Fladen grounds, in the Northern North Sea. The seapens and burrowing
megafauna component of the burrowed mud habitat falls across the entire potential area except for
within the small patch of sand and gravel habitat at the southern tip. One of two records of the tall
sea pen on the east coast of Scotland has been recorded in the southern part of this potential area
(~x30 individual sea pens observed on a single video transect in 2010), a species which is
classified as a nationally uncommon (Greathead et al 2007). The potential area has been shaped
to include one of the tunnel valleys comprising the Fladen Deeps or ‘The Holes’ – a key area of
geodiversity interest in Scotland’s Seas.
Size - The potential area for an MPA is 925km2.
Background to site development
Origins - The potential area was derived from the Fladen grounds Broad Search Area primarily to
represent sea pens and burrowing megafauna and the tall sea pen components of the burrowed
mud habitat away from the coast/offshore in OSPAR Region II. It also was included to represent
an example of the Fladen Deeps key geodiversity area. .
Features
Biodiversity - Burrowed mud (sea pens and burrowing megafauna, the tall sea pen).
Geodiversity – The potential areas falls within the Fladen Deeps key geodiversity area under the
Quaternary of Scotland block.
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Draft Conservation Objectives
For all biodiversity and geodiversity features the conservation objective has been set to conserve.
Data confidence
Age - All burrowed mud records collected within the last six years.
Coverage - Numerous burrowed mud habitat records distributed across the potential area for an
MPA with some clumping.
Source - The majority of the data on burrowed mud within the potential area for an MPA was
collected through Marine Scotland Science fisheries survey work. The extent of the tunnel valley
within the potential area has been determined using the UKHO Admiralty Chart.
Methods – Most of the supporting evidence for burrowed mud was collected using remote video,
with grab samples confirming seabed sediment type. Broadscale habitat modelling for burrowed
mud and offshore subtidal sands and gravels corresponds with benthic grab data.
Summary - Confident in presence of burrowed mud habitat components – sea pens and burrowing
megafauna and the tall sea pen. Data suitable for defining feature extent. Data on feature
condition is limited.
Summary of assessment against the MPA Selection Guidelines
Stage 1
Encompasses three MPA search feature priorities – burrowed mud (sea pens and
burrowing megafauna and tall sea pen components), offshore subtidal sands and
gravels and shelf deeps. Burrowed mud considered to be under threat/subject to
decline.
Stage 2
a. Contains combinations of features but not considered to be functionally linked.
b. The burrowed mud present is considered to have a high natural biodiversity. It is not
known whether or not the guideline is met for offshore subtidal sands and gravels as
there is no specific biotope information available with which to undertake an
assessment.
c. Contains examples of burrowed mud that are considered to be typical of the wider
Fladen Grounds and the boundary is considered large enough to represent a viable
example of the habitat. There is insufficient information available with which to
undertake an assessment with respect to many of the elements of guideline 2c for
offshore subtidal sands and gravels but it is noteworthy that the patch included is
not considered to be of appropriate size to be considered viable. Offshore subtidal
sands and gravels has not been considered further for the MPA search location as a
result of this. The tunnel valley feature is fully contained within the MPA search
location but is not considered to be of functional significance and so is not being
considered as a large-scale feature. The tunnel valley feature is however
considered part of the wider network of deep features making up the Fladen Deeps
key geodiversity area which is considered to be of scientific importance (Brookes et
al., 2011).
d. Based on the use of information on the sensitivity of burrowed mud to pressures
associated with activities to which they are exposed, it may be the case that
burrowed mud present may have been modified by human activity but it is notable
that sea pens are still reported to be present.
e. Within the MPA region it is considered that there is at least medium risk of
significant damage by human activities burrowed mud. These risks primarily relate
to otter trawling, demersal seine netting and cable and pipeline installation and
maintenance. The tunnel valley geodiversity feature is considered robust and is not
considered to be at risk.
Stage 3
The shape of the location has been influenced by the distribution of the tall sea pen to
the south-east of the potential area and a cluster of records of other sea pen species
likely to comprise examples of the sea pen and burrowing megafauna habitat
component of burrowed mud extending from the south to the north of the potential
area. The focus was to include data for characterising species of sea pen and
burrowing megafaunal habitat that reflect the typical abundance recorded for the
characterising species across the wider Fladen Grounds. The search location
encompasses the entirety of a tunnel valley feature that runs through the centre of the
search location.
Summary of assessment against the MPA Selection Guidelines
The regional risk assessment (see 2e above) identified that within OSPAR region II in
Scotland’s Seas there is a medium risk of significant damage to the burrowed mud
habitat. The risks relate primarily to bottom contact fishing and pipeline and cable
installation and maintenance.
Otter trawling, seine netting and set netting occurs within the Central Fladen potential
area for an MPA. It is likely that there is interaction between the burrowed mud features
and the bottom contact gear used. Further discussion is required with those involved in
using these types of gear to provide clarification on this interaction. The fisheries
guidance for burrowed mud recommends reducing effort through the use of spatial/
temporal measures. However, it also highlights the need for further research to
determine the required level of effort reduction to ensure burrowed mud habitats are
appropriately conserved.
Stage 4
Appropriate management would be determined through a process which would include
dialogue between stakeholders, scientists and fisheries managers. Suitable
management measures may include (but are not restricted to) temporary or seasonal
closure of selected areas, closure of the area within which tall sea pens have been
recorded, modification of gears or fishing practices or effort limitation. Marine Scotland
would lead discussions with UK and Non-UK stakeholders and The European
Commission on any measures recommended for management of fishing activities
within the potential area as fishing activities outside 12 nm (and outside 6nm where
non-UK fisheries have historic rights) are regulated through the Common Fisheries
Policy.
Pipeline and cable installation and maintenance would be managed through the
Environment Impact Assessment process.
There is therefore potential for management measures to be implemented successfully
and the conservation objectives of the MPA to be achieved. This will depend on a)
further discussions with those involved in fishing within the search location to gain a
better understanding of likely interaction between the features, otter trawling; and b)
research to better understand the relation between fishing intensity and the condition of
burrowed mud.
Stage 5
a. Burrowed mud* - is included on the OSPAR Threatened and Declining list and is
considered to be threatened in Scotland’s seas. A greater proportion of this habitat
is therefore being included within the network to achieve resilience for the feature.
Central Fladen would contribute to the conservation of the sea pens and burrowing
megafauna and tall sea pen components of the habitat and includes one of the two
records of tall sea pens in OSPAR region II. The potential area lies away from the
coast, within the deeper shelf geographic range for these components.
b. Fladen Deeps - The tunnel valley shelf deep feature is not considered to be of
functional significance to other features present or the wider marine environment,
but should remain under consideration on the grounds of its geodiversity
importance.
c. Offshore subtidal sands and gravels - Although there is a patch of offshore subtidal
sand and gravel habitat within the potential area this is not considered viable and is
therefore not recommended for inclusion to contribute to the broader representivity
of the feature within the network. The patch has been included within the boundary
of the area as it appears to be associated with the record of tall sea pens which is a
component of the burrowed mud habitat for which the Central Fladen area would be
recommended.
* Linkages for burrowed mud will be assessed using the results of the MSS
connectivity modelling work.
Assessment of activities / pressure interaction
The following is a brief summary of relevant activities to which the burrowed mud habitat in the
potential area is exposed. Further discussions with those involved in using the potential area will
enable a greater understanding of these activities and help determine whether additional
management is required.
Infrastructure (UK DEAL and UK Cable Protection Committee1
- There is one major telecommunication cable running through the central part of the north of
the location, which re-enters the south-east corner,
- There are two pipelines running across the southern part of the location.
Fishing >15m vessels (2006-2009 VMS data)
- Otter trawling: there is fishing activity throughout the Central Fladen site, the south western
portion of the site, coincident with the sandy sediment, is less intensively fished than the
north.
- Demersal seine netting: From the VMS data, the seine net fishery in the central Fladen
region is concentrated to the south of the Fladen Deeps with up to 125 hours activity
estimated between 2006 and 2009 in this area. There is some evidence of seine net activity
to the north of the Fladen deeps, but this is low by comparison (< 20 hours over four years).
- Set netting# (Danish shrimp fishery): Although, listed as “set netting” in the VMS data, the
most likely activity in this region is the Danish shrimp trawl fishery occurring to the
southwest of the Central Fladen site.
- Pelagic trawling and purse seining*
#
Gear codes for non-UK vessels based on EU vessel register primary gear coding, thus there is an
increased likelihood of misclassification error.
*Burrowed mud is not exposed to this activity.
The pressures associated with otter trawling, and to a degree seine netting and set netting, to
which burrowed mud habitat is sensitive include: removal of non-target species; surface and
subsurface abrasion/penetration; and changes in siltation. They are likely to interact with the
characterising species living within and on the surface of the burrowed mud habitat distributed
across the potential area.
The pressures associated with pipelines and cables to which burrowed mud habitat is sensitive:
physical change (to another seabed type), physical removal (extraction of substratum), sub-surface
abrasion/penetration.
Pelagic trawling and purse seining also occur across the potential area; however burrowed mud
habitat is not exposed to the pressures associated with these activities.
Options for management
The approach to managing Nature Conservation MPAs is set out in the MPA Management
Handbook and supporting guidance. This includes general provisions, such as the responsibilities
of public bodies for MPAs in exercising their functions. In addition to the general provisions, the
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Now UK Sub-sea cables
following options for management are being considered:
A. No additional management – risk of increasing levels of modification. In particular,
there is a risk that the remaining population of tall seapen may be reduced or lost.
Further research on feature/activity interaction and feature tolerance to pressures
may result in future implementation of measures
B. Managed access for demersal fishing – Appropriate management would be
determined through a process which would include dialogue between stakeholders,
scientists and fisheries managers. Suitable management measures may include (but
are not restricted to) temporary or seasonal closure of selected areas, closure of the
area within which tall sea pens have been recorded, modification of gears or fishing
practices or effort limitation. If appropriate management measures are introduced
resulting in an overall reduction in fishing pressure and increased protection of tall sea
pens, the biological community within the closed area would be expected to recover
to a more natural condition and the population of tall sea pens would be maintained
and may increase if conditions are appropriate. This option would provide an
opportunity for a well designed scientific study to improve the requirements for
sustainably managing this feature.
C. No access – The habitat will not be subject to further modification. If there are no
other unregulated pressures, recovery would be expected to take place at a natural
pace. This option would present to lowest risk of the site failing to achieve good
condition but would impose the highest cost on the fishing industry.
Options for managing the effects of pipeline and cable installation and maintenance would be
considered as part of the Environmental Impact Assessment for any development.
To support discussion with those involved in using the potential area, further detail (including
maps) will be provided in a Management Options paper.