Solway 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 SMR/OMR scale for most species; this will be included in Scotland’s next marine assessment.

At a SMR/OMR 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 Solway SMR, including changes in distribution and extent.

Marine Protected Areas

Progress in developing the Scottish MPA network

There are seven MPAs in the Solway 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 Solway SMR that contribute to the Scottish MPA network, including number of new MPAs introduced since 2012.

Note that in December 2020, the existing Upper Solway Flats & Marshes SPA was extended to form the Solway Firth SPA . 

Highlights from the various MPAs include:

There are seven MPAs in the Solway SMR which mainly protect estuarine habitats and associated features, such as wintering waterbirds.  The sediments within Luce Bay  and Sands SAC range from mixed-sized boulders, deep sediments and highly mobile fringing sands, all of which support rich plant and animal communities typical of a large embayment in south-west Scotland.  The Solway Firth SAC was designated for a number of features including the estuary itself, subtidal sandbanks and reefs, as well as river and sea lamprey. It is one of the least-industrialised and most natural large estuaries in Europe. Tidal streams in the estuary are moderately strong and levels of wave energy can be high and there is considerable seasonal fluctuation in water temperature, owing to the shallow nature of the estuary. The Solway Firth SPA straddles the border between England and Scotland. The flats and marshes of the Upper Solway form one of the largest continuous areas of intertidal habitat in the UK and is an important area for wintering waterbirds (ducks, geese, swans and waders), and gulls, and is a vital link in a chain of west coast UK estuaries used by migrating waterbirds. It is home to virtually the entire Svalbard population of barnacle geese over the winter months and the wider marine waters support some of the largest populations of wintering red-throated diver and common scoter in Scotland.

Progress in managing MPAs

The progress in implementing management for MPAs in the Solway 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 Solway 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 has been split out to reflect the different programmes of work.  These figures cannot be added together to provide a total number of SSSIs in which monitoring took place because of overlaps in coverage.  

Within the Solway SMR there are currently two Fisheries Orders in place for Luce Bay and Sands SAC and the wider Solway Firth, encompassing the Solway Firth SAC, Solway Firth SPA and two SSSIs. The order for Luce Bay and Sands SAC is focused on restricting demersal mobile gear in certain parts of the site, whereas the measure for the Solway Firth restricts the collection of cockles to ensure adequate prey resources for the protected birds of the SPA. Further fisheries measures are under discussion for the Solway Firth SAC.

Four of the MPAs within the SMR have been monitored by statutory bodies between 2012-2018.  The features monitored include seabed habitats, birds and fish.

Citizen science monitoring in the MPAs is carried out through the Wetland Bird Survey project organised by the British Trust for Ornithology. Wetland Bird Surveys have been carried out across three sites in the Solway to monitor species including Eurasian curlew, common redshank and common shelduck.

Information on MPA boundaries can be viewed in Marine Scotland’s NMPi. To find out more about specific MPAs, please visit NatureScot’s SiteLINK. 

Intertidal and continental shelf habitats

SMA2020 contains three relevant habitat assessments: intertidal seagrass beds, subtidal biogenic habitats, and the predicted extent of physical disturbance to the seafloor.  Although subtidal seagrass, maerl and blue mussel beds have been recorded within the region, no data are available on temporal changes in extent of these habitats and hence no status assessments could be made.  There are no records of serpulid aggregations, flame shell beds or horse mussel beds.  Despite the presence of intertidal seagrass beds in the region, no analysis of temporal trends could be carried out due to lack of time series data and hence the status assessment, which is dependent upon such information, could not be completed.  Modelling work was carried out as part of the assessment to predict the extent of physical disturbance to the seafloor more generally.

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 the SMRs.

Twelve per cent of the seafloor of the Solway SMR is predicted to experience no mobile fishery disturbance, which is the average for all SMRs and only 22% is predicted to be subject to high disturbance, which is the lowest level of any SMR (mean 50%) (Figure 3).  Patches of high predicted disturbance are scattered over the SMR and these strongly reflect the pattern of fishing pressure. The demersal fisheries prohibition within the Luce Bay and Sands SAC commenced in 2016 and so will have had little effect on the assessment, which covered the period 2012 - 2016.

Figure 3.  Predicted physical disturbance to the seafloor in the Solway 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 Luce Bay and Sands SAC will have had little effect on this assessment, although a seasonal prohibition has been in place since 2004.)

Priority Marine Features and birds (non-PMF)

Overview of recorded PMFs and birds

The Solway 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 Solway SMR

The Solway SMR has a total of 33 PMF habitats and species, and 30 marine bird species.  There are relatively lower PMF numbers in each of the habitat and species groups compared with other west coast SMRs.  Subtidal blue mussel beds are restricted to a few scattered locations in lochs and firths around Scotland, including the Solway Firth. Mudflats are found in the most sheltered areas of the Solway SMR, usually where large quantities of river-derived silt are deposited. The sediment is stable and animal communities are typically dominated by polychaete worms and bivalve molluscs.  The Solway SMR is important for the passage of migratory fish including sea and river lamprey, as well as salmon and sea trout, and provides an important nursery area for species such as skates and rays.  In winter, the Solway SMR is a stronghold for a variety of marine birds including surface-diving species such as red-throated diver, common scoter and goosander.  Red-throated divers tend to feed on fish, crabs and marine worms whilst common scoters feed mainly on bivalves and goosanders feed exclusively on small fish.

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

Monitoring of benthic habitats continues to be relatively restricted.  During this assessment period the majority of records were collected by government organisations (SEPA, NatureScot) and focused on just two habitats (maerl and intertidal seagrass beds).

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. 

Table 4.  Temporal frequency of PMF habitat records within the Solway 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.

Table 4 shows that citizen science surveys made a modest contribution to the knowledge of PMF distribution prior to 2012, and much less in later years.

Intertidal and subtidal seagrass beds have been recorded within the region (Figure 4).  There are pre-2012 records of intertidal seagrass beds in Loch Ryan and at four locations in Solway Firth including an extensive bed in Auchencairn Bay (Covey & Emblow, 1992).  SEPA identified two intertidal seagrass beds within Loch Ryan in 2010 and carried out baseline surveys at both in 2013 and assessed the total bed extent as 10.5 ha.  These beds form part of an ongoing Water Framework Directive monitoring programme that will enable status assessments to be undertaken in future years.  There are seven widely-distributed pre-1990 records of subtidal seagrass beds in Loch Ryan but no more recent observations of the habitat. 

Blue mussel beds are fairly widely distributed at the head of Luce Bay and on the sediment flats of the Solway Firth, where they extend into the subtidal off Southerness Point.  There have been no recent observations of the habitat.

Intertidal mudflats have been widely recorded in the embayments of the Solway Firth.  These records are mostly old (pre-2012) but have been supplemented by a 2012 survey of the Cree Estuary SSSI (ASML, 2014).

The presence of a maerl bed in the mouth of Luce Bay was confirmed by a 2012 survey of the Luce Bay and Sands SAC (Allen, Axelsson, Doran, & Dewey, 2014), which also recorded tide-swept algal communities at three locations in the bay.

Native oyster beds are known to have been present in Loch Ryan for several hundred years and the loch continues to support Scotland’s only native oyster fishery.

Figure 4.  Temporal pattern of records of selected PMF habitats for the Solway SMR.

Status and trend in grey and harbour seals

The Solway SMR is included in the Southwest Scotland seal management area (that encompasses the Clyde and Solway SMRs) and as such there are not specific assessments of the status and trend in grey and harbour seals in this SMR.  Within the combined Clyde and Solway SMRs there are relatively small numbers of both grey and harbour seals that are stable and the status of both species is assessed as ‘few or no concerns’.