Moray Firth SMR

This section summarises the information from the Marine Protected Areas (MPAs) and intertidal and continental shelf habitats assessments from SMA2020. It also provides information from the relevant case studies relating to Priority Marine Features (PMFs), with a focus on habitats.  Further work is required to enable assessment at a regional scale for most species; this will be included in Scotland’s next marine assessment.

At a regional scale for MPAs the focus is on the number of new MPAs, MPAs with new spatial management measures, and MPAs in which spatial management measures are in discussion, as well as recognising monitoring that has been undertaken between 2012-2018.  For the marine habitats, the focus is on interpreting the relevant intertidal and continental shelf habitat assessments – biogenic habitats, predicted extent of physical disturbance to the seafloor  (BH3) and intertidal seagrass beds.  For PMFs, a summary is provided of the changes in our understanding of the habitats of most relevance to the Moray Firth SMR, including changes in distribution and extent.

Marine Protected Areas

Progress in developing the Scottish MPA network

There are 25 MPAs in the Moray Firth SMR that contribute to the Scottish MPA network (see Table 1).  Some of these MPAs overlap completely or partially in terms of their spatial coverage and/or the features (habitats, species, etc.) they were set up to help conserve.  They are counted as separate MPAs because they have been established under different legislation which influences the way in which they are managed.  Also note that there are MPAs that straddle the boundaries between different SMRs.  Where this is the case, these MPAs have been counted as contributing to the MPA network in all of the SMRs in which they are present.  This means that the total number of MPAs in Scotland cannot be calculated through combining the SMR / OMR totals.  Please see the Marine Protected Area assessment which contains statistics for the Scottish MPA network as a whole.  

Table 1. Numbers of types of MPAs in the Moray Firth SMR that contribute to the Scottish MPA network, including the number of new MPAs introduced since 2012.

Note that in December 2020 there were another two MPAs designated in this region in addition to those in the table above, comprising one SPA (Moray Firth) and one Nature Conservation MPA (Southern Trench).

Highlights from the various MPAs include:

Within the Moray Firth SMR the majority of MPAs are focused on the protection of marine birds and their supporting habitats.  However, other features, such as marine mammals and benthic habitats and species, are also protected.  It includes a number of SPAs, such as the East Caithness Cliffs SPA, which supports internationally important numbers (i.e. up to 300,000 individuals) of breeding seabirds including common guillemot, razorbill and herring gull.  There are also internationally important populations of wintering waterbirds.  The Cromarty Firth SPA, for example, holds a winter peak mean of 30,200 individuals, comprising around 14,800 wildfowl and 15,400 waders.  The Moray Firth SAC covers a large part of the inner Moray Firth and provides protection for the most northerly resident population of bottlenose dolphins.  The Southern Trench Nature Conservation MPA takes its name from the 58 km long, 9 km wide and 250 m deep trench running parallel to the coast that was carved out by glaciers. This important geodiversity feature also contains rock features thought to be over 250 million years old. The trench functions as a nursery ground for juvenile fish and the thick, soft mud covering the trench floor is home to an assortment of mud-loving animals.  Minke whale and an oceanic front are also features of this MPA.

Noss Head MPA supports the largest known horse mussel bed in Scotland.  Horse mussels are long-lived, many survive for more than 25 years and some may live for more than 50 years.

Progress in managing MPAs

The progress in implementing management for MPAs in the Moray Firth SMR is summarised in Table 2.  This includes information on where spatial management measures are in place and where they are under discussion.  It also includes information on the number of MPAs that have been monitored, whether by statutory bodies or through citizen science.

Table 2. Summary of progress in managing Marine Protected Areas in the Moray Firth SMR

Note that the spatial measures listed in the table are in addition to the protection provided as a result of consideration of activities/developments through licensing and consenting processes. Also, the monitoring of birds, mammals and habitats within SACs and SSSIs has been split out to reflect the different programmes of work.  These figures cannot be added together to provide a total number of SSSIs and SACs in which monitoring took place because of overlaps in coverage.  

There are four Nature Conservation Orders (NCOs) in place that cover a range of SSSIs, SPAs and SACs. The NCOs restrict all shellfish extraction within the areas they cover, apart from the Morrich More and Dornoch Firth NCO 1995 which has an exception for mussel extraction related to a fishery in this area (although not currently active). There is a Fisheries Order in place that covers parts of the Moray Firth SAC and Dornoch Firth and Morrich More SAC and another which covers Noss Head MPA, both of which restrict the use of demersal mobile fishing gear. Further management measures for fishing activities are under discussion for Moray Firth SAC, Dornoch Firth and Morrich More SAC and East Caithness Cliffs SPA.

During this assessment period the majority of the MPAs in this SMR have been monitored at least once by the statutory bodies.  Monitoring has covered seabirds, wintering waterbirds, intertidal and subtidal habitats, and some mammals.  Bottlenose dolphins within the Moray Firth SAC continue to be monitored annually through the long-term photo-identification programme led by the University of Aberdeen’s Lighthouse Field Station. Seal populations continue to be monitored via a collaboration between the Sea Mammal Research Unit (SMRU) and NatureScot.

Citizen science monitoring of protected wetland birds in the Moray Firth has been carried out through Wetland Bird Surveys organised by the British Trust for Ornithology. Monitoring takes place across 11 sites in the network and includes species such as Eurasian oystercatchers, Eurasian curlews and greater scaup. Sightings of bottlenose dolphins in the Moray Firth SAC are recorded by volunteers through the Whale and Dolphin Conservation Shorewatch Sightings programme.

Information on MPA boundaries can be viewed in Marine Scotland’s NMPi. To find out more about specific MPAs, please visit NatureScot’s SiteLINK.  Detailed reports on habitat monitoring are referenced in Further reading – seabed habitat monitoring reports.

Intertidal and continental shelf habitats

SMA2020 contains three relevant habitat assessments: intertidal seagrass beds, subtidal biogenic habitats, and predicted extent of physical disturbance to seafloor.  Although intertidal seagrass beds are present within the region, their status could not be assessed due to the lack of time series data on which the assessment method depends.  Assessment was, however, completed for subtidal biogenic habitats.  Modelling work was carried out as part of the assessment to predict the extent of physical disturbance to the seafloor more generally.

Biogenic habitats

The SMA2020 subtidal biogenic habitats status assessment is based on temporal changes in extent of six habitat types: seagrass beds, serpulid aggregations, flame shell beds, maerl beds and horse and blue mussel beds.  Serpulid aggregations and flame shell beds are not known to occur in the SMR.  Beds of subtidal seagrass have been recorded, but no data are available on temporal changes in their extent, and hence only blue mussel and horse mussel beds were considered in the SMA2020 assessment. 

Monitoring of the largest known horse mussel bed in Scottish waters off Noss Head by SNH/Marine Scotland in 2017 (Moore, 2019) found the distribution of the bed to be consistent with earlier mapping of the feature based on records from 2010 to 2013 (Scottish Natural Heritage, 2014; Moore, 2019).  Bed extent was considered to be stable over this period at approximately 4.1km².  The bed was only identified in 2010 (MMT, 2010) and so longer-term trends are unknown.

Both intertidal and subtidal blue mussel beds are present in the Dornoch Firth and have supported a fishery for hundreds of years. In 2010 scattered subtidal beds occupied an area of around 218 ha (Bromham, 2010), with mapping provided by Cook, Cordingley, Woolmer, & Sanderson (2016). A subsequent survey in 2015-16 (Cook et al., 2016) recorded only two relict patches occupying a total area of 1 ha. The loss of habitat was considered to possibly involve factors such as poor recruitment success and increased levels of post-settlement mortality. 

On the basis of the reduction in the blue mussel bed extent in the Dornoch Firth, the SMA2020 status category assigned for the region was ‘Some concerns’, although the confidence in this assessment is considered to be low.  The extent of both horse mussel and blue mussel beds in the SMR as a whole is poorly known and there are no temporal trend data for any mussel beds in the region apart from the previously mentioned Noss Head and Dornoch Firth beds.  The local blue mussel bed extent reduction could be offset by gains elsewhere, and the relative importance of natural versus anthropogenic drivers of temporal change is inadequately understood.

1.1 Predicted physical disturbance to the seafloor

To assess physical disturbance to seafloor habitats SMA2020 employed a modelling approach which generates a map of predicted relative disturbance levels from demersal fishing activity on a scale of 0 (zero) to 9 (severe).  The map was produced by the combination of information on the distribution of habitats, the sensitivity of the habitats (and species present to varying degrees) and the fishing pressure from demersal trawling, dredging and seine netting.  Fishing pressure information was derived from Vessel Monitoring System (VMS) data from 2012 - 2016 and was categorised as either surface abrasion (disturbance of surface and upper layers of sediment) or sub-surface abrasion (disturbance to a depth of >3 cm).  The final predicted disturbance index utilises the greater of these two pressure values and for descriptive purposes has been categorised as no disturbance (0), low disturbance (1-4) and high disturbance (5-9).

It should be emphasised that this method does not measure disturbance to seabed habitats, but predicts relative levels of disturbance. These relative levels are dependent upon the accuracy of habitat data and sensitivity assessments.  Many of the habitat data are derived from modelling and there is a low level of confidence in its accuracy.  Geographical variation in the accuracy of the sensitivity information employed is likely to be great, being dependent upon the level and quality of information used locally.  A significant limitation of the method is that during the assessment period pressure data were only available for vessels >12 m, which has probably resulted in an underestimation of disturbance for all SMRs.

Predicted habitat disturbance by mobile demersal fishing for the Moray Firth SMR is slightly higher than the average for SMRs in terms of the proportion of the seabed with 57% high disturbance compared to an average of 50% for all SMRs (Figure 3).  Nine per cent of the seabed is predicted to experience no disturbance (average of 12% for all SMRs).  Areas showing the highest predicted levels of disturbance, which are principally regions of coarse sediments located off the Grampian coast and east of Noss Head, correspond to higher levels of surface abrasion sensitivity and surface abrasion pressure.  Areas of mud in deeper waters off the Grampian coast also show high predicted levels of disturbance, with low levels associated with sandy sediments off the Dornoch Firth.  The demersal fisheries prohibition that covers the Noss Head MPA commenced in 2016 and so will have had little effect on the outcome of the assessment, which covered the period 2012 - 2016.

Figure 3.  Predicted physical disturbance to the seafloor in the Moray Firth SMR and prohibition areas for all mobile demersal fishing.  (Note that the prediction of physical disturbance covered the period 2012-2016 and so the fisheries prohibition relating to the Noss Head MPA will have had little effect on this assessment.)

Priority Marine Features and birds (non-PMF)

Overview of recorded PMFs and birds

The Moray Firth SMR supports a range of PMFs and breeding seabirds as well as wintering waterbirds (i.e. waders, estuarine waterfowl, seaduck and coastal water feeding birds) as detailed in Table 3. 

Table 3: Details of PMFs, seabirds, and wintering waterbirds found in the Moray Firth SMR,

There are 47 PMFs and 32 marine birds recorded in this region, which is relatively high compared to other SMRs / OMRs on the east coast.  There are blue mussel beds in the Dornoch Firth and Moray Firth.  The fishery in the Dornoch Firth was once the largest mussel producer in the UK with landings of over 2,500 tonnes in 1991 (McKay & Fowler, 1997), although since then the bed has declined and the fishery is no longer active.  Although in general relatively scarce on the east coast of Scotland, the Moray Firth supports a number of sizeable seagrass beds of different species including Zostera marina and Z. noltii. Ruppia maritima is found intertidally in the Cromarty Firth.  The Moray Firth is an important spawning and nursery area for herring, which is an important prey species for marine mammals.  There are also internationally important populations of both wintering waterbirds and breeding seabirds, which are protected by the MPA network. 

Progress in understanding of intertidal and continental shelf habitats listed as PMFs

Much of the earlier work in this region focused on investigations of the distribution and condition of habitats, particularly in relation to the establishment and monitoring of SSSIs, SACs and MPAs, but since 2012 the emphasis has changed to improving understanding of the distribution of species and habitats of conservation importance, including PMFs and MPA protected features.

The temporal sequence of records of all PMF habitats is provided in Table 4, based on inclusion in the Marine Recorder (2021) and GeMS (2021) databases, as well as identified additional sources.  Associated commentary, however, is restricted to PMFs for which the information has the potential to inform regional marine planning.  For example, some PMFs are excluded on the basis that they are very widely distributed and for which the records represent a small proportion of their likely distribution, such as several of the kelp habitats.  The geographical distribution of records of selected PMFs is shown in Figure 4.

Citizen science records have generally made a modest contribution to knowledge of PMF distribution in this SMR, accounting for 6% and 16% of records before and after 2012 respectively, with the notable exception of kelp (Table 4), with all kelp bed records being derived from Seasearch surveys.

Blue mussel beds are widely distributed in the inner region of the Moray Firth (Figure 4).  However, the only records of the habitat since 2011 relate to the Dornoch Firth.  A 2015 - 2016 survey of the mussel beds (Cook et al., 2016) found the major intertidal bed to be of similar extent and to support mussels of a similar size and condition to values reported for the bed in 2012 (Bromham, 2012).  However, the 2015 - 2016 survey recorded a considerable reduction in the extent of subtidal blue mussel beds in the Firth, from 218 ha in 2010 to 1 ha in 2015 - 2016 (Cook et al., 2016).

Most of the recent work on horse mussel beds in the SMR by NatureScot and Marine Scotland has been directed towards refining knowledge of the extent of the large Noss Head bed (Moore, 2015, 2019), although new beds were recorded by Seasearch in 2015 off the mouth of Cromarty Firth and during a blue mussel bed survey by Cook et al. (2016) (cited in Highland Council, 2017) in the Dornoch Firth in 2016.

Nephrops burrow density surveys carried out by Marine Scotland from 2007-2016 indicate that the burrowed mud habitat is extensively distributed along the southern section of the SMR, and this is broadly reflected by the records of burrowed mud biotopes.  Post-2012 surveys by NatureScot and Marine Scotland have filled gaps in the distribution of the habitat (Moore, 2015, 2016, 2017, 2019).

The distribution of intertidal seagrass beds in the Cromarty Firth was poorly known before a 2015 survey of the beds in Nigg Bay and Udale Bay (SEPA, unpublished).  This revealed extensive beds, which represented the largest coverage of the habitat recorded by SEPA in one water body (324 ha).  A Highland Council 2020 survey along the northern shore of the Dornoch Firth (Seagrass Spotter, 2021) confirmed the persistence of a bed last observed in 1973 (Wells & Boyle, 1973).

Table 4.  Temporal frequency of PMF habitat records within the Moray Firth SMR obtained from GeMS (2021), Marine Recorder (2021) and other sources.  The numbers of All records are given, as well as those from Citizen Science (CS) surveys alone.