Forth and Tay 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 Forth and Tay SMR, including changes in distribution and extent.

Marine Protected Areas

Progress in developing the Scottish MPA network

There are 16 MPAs in the Forth & Tay 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/OMRs.  Where this is the case, these MPAs have been counted as contributing to the MPA network in all of the SMRs/OMRs 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 Forth & Tay SMR that contribute to the Scottish MPA network, including the number of new MPAs introduced since 2012.

Note that in December 2020 there was another one SPA designated in this region in addition to those in the table above (Outer Firth of Forth and St Andrews Bay Complex).

Highlights from the various MPAs include:   

Within the Forth & Tay SMR the majority of MPAs are focused on the protection of marine birds and their supporting habitats including intertidal areas and islands.  The Tay and Eden estuaries and the Montrose Basin, along with many of the intertidal areas of the Forth Estuary, support nationally and internationally important populations of wildfowl and wading birds, including pink-footed goose, common redshank, red knot, dunlin and Eurasian oystercatcher, within a number of SPAs, Ramsar sites, and SSSIs. The Forth Islands SPA supports internationally important numbers of seabirds, including the largest breeding northern gannet colony in the world on Bass Rock.   Rare roseate terns have recently bred on the Isle of May – the only place in Scotland where they breed.  There are important grey seal breeding sites on the Isle of May and at Fast Castle Head.  The Firth of Tay and Eden Estuary SAC was designated for its harbour seal population, but numbers along much of the east coast have declined dramatically since 2001.   The East Coast of Scotland Other Area Based Measure covers an extensive area (21,320 km²) for the conservation of sandeels, in recognition of their importance as a prey species of various seabirds including black-legged kittiwake. 

Progress in managing MPAs

The progress in implementing management for MPAs in the Forth & Tay 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 Forth & Tay 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 SSSIs and SACs 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.  

The Firth of Forth Nature Conservation Order covers the Firth of Forth SPA and SSSI and prevents the collection of cockles except for personal and scientific purposes. This was put in place in relation to the protected bird species using the Firth of Forth SPA and SSSI. Elsewhere in the region there is a fisheries order for Berwickshire and North Northumberland SAC, which also encompasses the Eyemouth and St Abbs Voluntary Marine Reserve. This restricts use of demersal mobile gear to one nautical mile from mean high water springs. There is also a Fisheries Order in place that restricts demersal mobile gear in part of the Firth of Tay and Eden Estuary SAC. Further management measures are under discussion for the Firth of Tay and Eden Estuary SAC and the Isle of May SAC.

During this assessment period the majority of the MPAs have been monitored at least once by the statutory bodies.  Monitoring has covered seabirds, wintering waterbirds, mammals and subtidal habitats.  Monitoring of some sites has been carried out through agreements with organisations such as the Sea Mammal Research Unit, Scottish Wildlife Trust and the National Trust for Scotland.

Thirteen Ramsar, SSSI and SPA sites have been monitored by citizen science in the Forth and Tay SMR. Monitoring in the Forth Islands SPA is carried out by the Forth Seabird Group and they monitor all the protected features of this site, i.e. Atlantic puffins, common guillemots and sandwich terns, except for northern gannets. Monitoring of the other sites designated for birds is carried out through the Wetland Bird Survey project organised by the British Trust for Ornithology. Reefs in the Berwickshire and North Northumberland Coast SAC and the Isle of May SAC are monitored by Seasearch. The Firth of Forth SSSI has been monitored through surveys carried out as part of The Shore Thing, an initiative of the Marine Biological Association.

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 the seafloor.  Assessment of the status of subtidal biogenic habitats is based on temporal reductions in extent of six habitat types: seagrass beds, serpulid aggregations, flame shell beds, maerl beds and horse and blue mussel beds.  Of these habitats, only blue mussel and horse mussel beds have been recorded in the SMR.  However, no assessment was possible due to the lack of temporal data on which the method relies.  SMA2020 did, however, include the results of a programme of trial sampling of intertidal seagrass beds to determine their ecological status or health, and modelling work was carried out to predict the extent of physical disturbance to the seafloor more generally.

Intertidal seagrass

The methodology involved the employment of the Water Framework Directive seagrass tool (WFD-UKTAG, 2014) which provides an assessment of ecological status for a water body based on temporal changes in seagrass bed extent, percentage cover and the number of seagrass species present. The tool permits the calculation of the Ecological Quality Ratio (EQR) which can be divided into bands ranging from 0.8 - 1 (high status - zero or minimal disturbance) to 0.0 – 0.2 (bad status – severe disturbance).

SEPA carried out repeat surveys at four locations (Eden Estuary, Montrose Basin, Lower and Middle Forth Estuary) and recorded little or no reduction in habitat extent (Table 3).  Increases were considered to be possibly influenced by changes in the intensity of surveying and the availability of aerial imagery to aid bed extent measurement for some surveys.  Temporal variation in percentage cover was in part possibly explicable in terms of natural variation.

Despite all four water bodies lying within the high ecological status band (Table 3), the overall SMA2020 assessment for the SMR was “Lack of evidence/robust assessment criteria” due to the low number of surveys carried out.  To reduce the significance of natural, inter-annual variability ideally surveying should be performed annually and trends identified using a five-year rolling mean.  Also, some of the temporal change observed may be due to methodological change, particularly regarding the intensity of surveying and so additional work is required before a firm status assessment of intertidal seagrass within the SMR is possible. 

Table 3.  Classification of the health or status of water bodies based on application of the WFD seagrass tool with survey details.  Status is quantified by the Ecological Quality Ratio (EQR) and ascribed to a corresponding status class band.

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.

Predicted habitat disturbance by mobile demersal fishing for the Forth and Tay SMR is average for SMRs in terms of the proportion of the seabed with 48% high disturbance compared to an average of 50% for all SMRs (Figure 3).  Thirteen per cent of the seabed is predicted to experience no disturbance (average of 12% for all SMRs).  High predicted disturbance levels closely mirror surface abrasion pressure (and to a lesser extent subsurface abrasion pressure) and are mainly concentrated on the muddy Nephrops grounds of the Firth of Forth, with smaller patches on harder sediments north of this.

Figure 3.  Predicted physical disturbance to the seafloor in the Forth and Tay SMR and prohibition areas for all mobile demersal fishing.

Priority Marine Features and birds (non-PMF)

Overview of recorded PMFs and birds

The Forth & Tay 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 Forth & Tay SMR

There are 37 PMFs and 33 species of marine birds recorded in this region, which is relatively low compared to SMRs on the west coast.  There are, however, a number of records of intertidal and benthic habitat PMFs not commonly found on the east coast, as well as large areas of specific PMFs such as intertidal mudflats in the Montrose Basin, the Firth of Tay and the Firth of Forth.  The Firth of Tay is one of the few locations around Scotland where Mytilus edulis beds on sublittoral sediment are found and the most southerly record of horse mussel beds on the east coast of Scotland is off the Berwickshire coast.

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

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.

Much of the earlier work in this region focused on investigations of the distribution and condition of habitats, particularly in relation to broadscale habitat mapping and monitoring of SACs.  Since 2012 Seasearch divers have carried out eight surveys in the SMR, supplementing knowledge of the distribution of kelp beds, but otherwise little work on PMF habitats has been carried out, apart from SEPA monitoring of seagrass beds. 

The 2013 - 2018 SEPA seagrass surveys have contributed greatly to knowledge of habitat distribution and condition in the Firth of Forth, Eden Estuary and Montrose Basin areas and represent the establishment of an ongoing programme for monitoring habitat health.  A 2020 East Lothian Council survey of Bellhaven Bay has contributed many records for a previously undocumented intertidal seagrass bed (Seagrass Spotter, 2021).

Other recent PMF habitat finds off St Abb’s Head include a horse mussel bed (Heriot-Watt University, 2014 unpublished) and a 2016 Seasearch record of a tide-swept algal community.

Table 4.  Temporal frequency of PMF habitat records within the Forth and Tay  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.

Figure 4.  Temporal pattern of records of selected PMF habitats for the Forth and Tay SMR.

Status and trend in grey and harbour seals

Grey seal pup production at the major breeding sites – Isle of May and Fast Castle Head – has been monitored biennially and has shown an increasing trend in numbers and their status is assessed as ‘few or no concerns’.  In contrast harbour seal numbers have suffered an historical decline of around 95% since the early 2000s although since 2012 their numbers are little changed albeit at a much-reduced level and their status is assessed as ‘some concerns’.