Moray Firth SMR

Location and physical characteristics

Figure 1: Moray Firth Scottish Marine Region. The thicker white line delineates the extent of the Moray Firth SMR. For a map of all SMRs and OMRs, see Figure 5 here

Coastline length (km) 985
Sea area (km2):  5,876
Deepest point (m) 256
Shallowest point (m) coastline
Average depth (m) 50
Tides (m) 2.2 – 3.8
Salinity 34.18 – 34.79
Sea surface temperature (°C) 7.5 – 13.9

 

The Moray Firth SMR extends westward from a point to the west of Fraserburgh to Inverness and then north to John O’ Groats, extending 12 nautical miles offshore from the coast (Figure 1). There is a gradual transition from the more estuarine and sheltered conditions of the three inner firths (i.e. Beauly, Cromarty and Dornoch Firths) to the open sea of the outer firth. This SMR receives a large freshwater input from these inner firths and the river Ness, that influences the salinity of adjacent coastal waters. The currents in this region include the general southward coastal flow. The pre-dominant direction of tidal currents is parallel to the coastline. Conditions in autumn and winter can be rough in the North Sea because of the relatively long, uninterrupted fetch and prevailing northerly and easterly winds, but is sheltered at times from westerly winds.

The solid geology is based on metamorphic, Dalradian and Moine rocks, which have been intruded by several granitic masses. These rocks subsequently underwent faulting and metamorphosis in the Caledonian Orogeny (period of mountain building) and are overlain by Devonian rocks. The Great Glen Fault influences the rock formations from the Devonian age and earlier. These north-northeast trending faults continue from Inverness parallel to the coastline and then seawards into the Moray Firth from Tarbat Ness. Rapid changes in sea level and high sedimentation rates in the Quaternary and glaciation during this time has produced features of both erosion and deposition. Following ice-melt the land was submerged to about 25 m beneath the present sea level and the inner Firths were produced by the drowning of valleys.

 Seabed sediments in the Moray Firth SMR consist of a relatively thin, uniform cover of bottom sediments of mainly Holocene age resting on glacial and periglacial sediments and solid rock. Sediment distribution reflects the glacial history and the present hydrodynamic regime, with a close correlation between increased depth and decreasing grain size due to the relative importance of wave energy to sediment transport processes.

 

Productive

The Moray Firth SMR extends along the northern coast of Aberdeenshire and Moray to Inverness and then northwards incorporating the Cromarty Firth and Dornoch Firth, progressing to John O’ Groats. Fishing has been a very significant part of the history of towns such as Macduff and Buckie. These coastal towns were involved in the catching and exporting of fish as well as the construction of fishing vessels. Ship building continues today in Macduff following diversification into pilot boats and survey crafts.

The Moray Firth SMR is popular with tourists and those wanting to see the dolphins that live in the area as well as the northern gannets which return on an annual basis to Troup Head to breed, along with common guillemots, black-legged kittiwakes, razorbills and Atlantic puffins.

The Productive Assessment was undertaken, with a focus on 2014 – 2018, on a sectoral basis. For a number of Sectors, including renewables, carbon capture and storage and aggregates, there was no activity within the Moray Firth SMR during the period 2014 – 2018. However, for many Sectors, there were changes over the period 2014 – 2018 (Figure 2).

Figure 2: Changes that have taken place in the Moray Firth SMR by Sector. Although the period 2014 – 2018 inclusive has been used where possible, there are some entries when a slightly different time period has been used. Information on mussel production for Moray Firth SMR has been merged with West Highlands and North Coast SMR’ to avoid disclosure. Information on seaweed harvesting for Moray Firth SMR has been merged with the North Coast SMR to avoid disclosure.

Pressures from human activities

As part of SMA 2020, an assessment of the main pressures from human activities in each of the Scottish Marine Regions and Offshore Marine Regions was undertaken through a MASTS-led workshop. The process and outcomes are presented in detail in the Pressure from Activities section. Five main pressures identified for the Moray Firth SMR ordered as per the MASTS-led Pressure Assessment Workshop were:

Priority [1] Pressure (FeAST classification) [2] Main healthy and biologically diverse components affected [3] Main contributing FeAST activity /activities to pressure [4] Associated productive assessments [5]
1 Removal of target species (including lethal)
  • Fishing - Bottom otter trawling and pair trawls (OTB, OTT, PTB, TB, TBN)
  • Fishing - Creeling and potting (FPO)
  • Fishing - Scallop dredging (DRB)
2 Removal of non-target species (including lethal)
  • Fishing - Bottom otter trawling and pair trawls (OTB, OTT, PTB, TB, TBN)
  • Fishing - Creeling and potting (FPO)
  • Fishing - Scallop dredging (DRB)
3 Physical change (to another seabed type)
  • Extraction – Dredging (capital and maintenance)
  • Fishing - Scallop dredging (DRB)
4 Surface/Sub-surface abrasion/penetration
  • Extraction – Dredging (capital and maintenance)
  • Fishing - Bottom otter trawling and pair trawls (OTB, OTT, PTB, TB, TBN)
  • Fishing - Creeling and potting (FPO)
  • Fishing - Scallop dredging (DRB)
5 Underwater noise
  • Extraction – Dredging (capital and maintenance)
  • Fishing – any gear
  • Infrastructure - Coastal (ports, marinas, leisure facilities)
  • Military activities – Sonar use
  • Shipping
  • Tourism & recreation

Clean and safe

The assessments cover eutrophication, hazardous substances, marine litter, noise and microbiology and algal toxins which have the potential to impact on habitats and species as well as being a consequence of human activity. Although sources of litter or contaminants may be local, there are cases when the source is some distance from the impacted area. The main findings for the Moray Firth SMR are:

Eutrophication 

Highest nutrient inputs came from the most populated areas of Scotland including the Moray Firth. However, concentrations were below assessment criteria and relatively stable. In addition, . Overall, the Moray Firth SMR showed no evidence of eutrophication as a consequence of nutrient enrichment.

Hazardous substances

Hazardous substances (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and heavy metals (Hg, Cd and Pb)) assessments in sediment and biota (fish and shellfish) were undertaken at the scale of the five Scottish biogeographic regions: Atlantic North-West Approaches, Irish Sea (Clyde and Solway), Minches and Western Scotland, Scottish Continental Shelf and Northern North Sea. The Moray Firth SMR is in the Northern North Sea biogeographic region. Contaminant concentrations in the Northern North Sea biogeographic region were generally above background but below concentrations where adverse effects could occur. In addition, concentrations in sediment and biota were stable or declining for all hazardous substances measured. Several biota and sediment sites in the Northern North Sea biogeographic region were in the Moray Firth SMR; these sites were typical of the Northern North Sea biogeographic region, with no major concerns. However metal inputs were some of the highest across all the regions and there was an increasing trend for mercury.

A number of biological effects were also measured, and assessments undertaken at the scale of the five Scottish biogeographic regions. Assessment of imposex in dog whelks, an indicator of tributylin (TBT) contamination, included three sites in the Moray Firth SMR. Results showed that imposex at most sites in this area indicated that concentrations of TBT in the marine environment are not causing significant harm. However, imposex at one site was at an unacceptable level The other contaminant-specific biological effects (PAH bile metabolites and 7- ethoxyresorufin O-deethylase (EROD) activity) in the Northern North Sea biogeographic region were consistent with the hazardous substances and showed a limited exposure to contaminants. The Northern North Sea biogeographic region showed an increase in fish disease in some years but this could not be linked to exposure to contaminants. There was only one fish site assessed for biological effects, including PAH bile metabolites, EROD and fish disease, in the Moray Firth SMR, and results were typical of the Northern North Sea biogeographic region.

Marine litter

Due to the lack of assessment criteria for marine litter, beach litter and microplastic, status assessments were not possible. However, litter and microplastics are present in all SMRs, including the Moray Firth SMR. The Moray Firth SMR has a relatively low concentration of microplastics in surface water (< 5,000 microplastics per km2 of sea surface).

Seafloor litter was assessed at the scale of the biogeographic regions; the Moray Firth SMR is included in the Northern North Sea biogeographic region. The evidence indicates that there is no consistent trend in seafloor litter density between 2012 to 2018 inclusive for the Northern North Sea biogeographic region.

Beach litter was also assessed in the Moray Firth SMR. In general, most beach litter categories are showing decreasing trends, apart from those related to the marine industries of shipping and fishing, which are showing gradual increasing trends.

Noise

There are limited noise data for the Moray Firth. Continuous noise data were collected in 2013 and 2014 as part of the East Coast Marine Mammal Acoustic Study (ECOMMAS). Overall, the continuous noise levels at each site, including those in the Moray Firth SMR, are broadly similar. Noise levels in the 125 Hz one-third octave band are predominantly within the range 80 – 120 dB re 1 μPa rms, and the modes of these distributions lie between 84 – 95 dB re 1 μPa rms. Very few impulsive noise data were reported for this SMR, but it is likely that impulsive noise may increase; offshore wind farm construction work is likely to use impact pile driving, which will increase the levels of impulsive noise. It is not possible to do a status assessment as there are no assessment criteria to say what levels of noise are harmful, and not sufficient years of data to carry out a trend assessment.

Microbiology

A number of bathing waters in the Moray Firth SMR are assessed according to levels of Escherichia coli and intestinal enterococci. In the latest classification (2018) none were classified as Poor.

A number of marine algal species produce biotoxins which, by accumulation in bivalve molluscs such as mussels and oysters, can cause human illness when these shellfish are eaten. Both biotoxins and phytoplankton are routinely monitored in classified shellfish production areas under Regulation (EU) 2017/625. Such monitoring took place within the Moray Firth SMR between 2010 and 2016. Concentrations of both diarrhetic and paralytic shellfish toxins exceeded regulatory limits (RL) in 2012 and 2014, but no samples were above RL for amnesic shellfish toxins.

Healthy and biologically diverse

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.

Type of MPA

Abbr.

Total no. of MPAs

No. of new MPAs 2012-2018

Nature Conservation MPA

MPA

2

2

Ramsar

-

4

0

Site of Special Scientific Interest

SSSI

11

0

Special Area of Conservation

SAC

2

0

Special Protection Area

SPA

6

0

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.  

 

Type of MPA

Spatial measures in place pre-2012

New spatial measures in place 2012-2018

Spatial  measures in discussion 2012-2018

No. of MPAs monitored by statutory bodies 2012-2018

No. of MPAs monitored via citizen science 2012-2018

Nature Conservation MPA

N/A

1

1

1

0

Ramsar

0

0

0

1

 

3

Site of Special Scientific Interest

5

0

0

Birds

7

Birds

5

Mammals

0

Mammals

0

Habitats

1

Habitats

n/a

Special Area of Conservation

2

0

2

Mammals

2

Mammals

1

Habitats

1

Habitats

n/a

Special Protection Area

3

0

0

2

3

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,

Priority Marine Features (PMFs; grouped habitats and species) and birds

No. of species/

habitats recorded

Intertidal and continental shelf habitats

10

Fish[1]

21

Mammals (regularly occurring)

11

Shellfish & other invertebrates

5

Seabirds[2] (non-PMF) – breeding

19

Wintering waterbirds[3] (non-PMF) – non-breeding

13

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.

PMF

<2012

2012-2018

>2018

 

All

CS

All

CS

All

CS

Blue mussel beds (intertidal)

93

0

10

 

0

0

0

Blue mussel beds (subtidal)

22

0

10

0

0

0

Burrowed mud

31

0

20

0

0

0

Burrowed mud or Inshore deep mud with burrowing heart urchins

12

0

0

0

0

0

Horse mussel beds

121

0

31

1

0

0

Intertidal mudflats

88

0

0

0

0

0

Kelp and seaweed communities on sublittoral sediment

1

1

0

0

0

0

Kelp beds

39

38

9

9

6

6

Low or variable salinity habitats

2

0

0

0

0

0

Maerl or coarse shell gravel with burrowing sea cucumbers

0

0

1

0

0

0

Seagrass beds (intertidal)

239

0

126

0

19

0

 

Seagrass beds (subtidal)

2

0

0

0

0

0

Tide-swept algal communities

4

3

0

0

0

0

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

Status and trend in grey and harbour seals

Grey seal pup production is monitored biennially and has shown little or no change in the 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 28% in the early 2000s although since then their numbers are little changed albeit at a reduced level and their status is assessed as ‘some concerns’. 


[1] Records from International Bottom Trawl Surveys from MSS.

[2] Records of seabirds during breeding season only, from BTO Bird Atlas.

[3] Records of birds during the non-breeding season, from the BTO Bird Atlas

Climate change

There is good evidence that climate change is driving changes in the physical, chemical and biological conditions of the marine environment but the current evidence base limits the ability to draw conclusions at the scale of the individual marine regions, including Moray Firth SMR. This is a combination of the lack of comprehensive spatial coverage of key monitoring programmes, the relatively short time series, and the complex linkages of climate change impacts in the marine environment.

Increasing concentrations of atmospheric greenhouse gases have caused more energy to be trapped within the Earth’s atmosphere, land and ocean. Approximately 90% of this excess energy has been absorbed by the ocean, resulting in warming ocean temperatures (see Temperature assessment and Climate change Sea temperature assessment).

The increasing concentration of carbon dioxide, one of these greenhouse gases, has the additional consequence of driving a reduction in the pH of the ocean, a process known as ocean acidification (see Ocean acidification assessment and Climate change Ocean acidification assessment).

Mean sea level is rising due to increased contributions of freshwater from melting of land-based ice (glaciers and the polar ice sheets) and due to thermal expansion of water (see Sea level and tides assessment and Climate change Sea level assessment).

The warming temperatures also result in lower oxygen concentrations due to fact that warm water holds less oxygen and changes in stratification further influence oxygen concentrations (see Dissolved oxygen assessment and Climate change Dissolved oxygen assessment). Together with increased metabolic rates in organisms resulting in increased respiration, oxygen depletion has a severe impact on marine organisms due to the impact on metabolic processes.

These changes in the physical environment are also having an impact on marine life, such as changes to their metabolism, changes in seasonality and the timing of events in natural cycles, and changes in their distribution. These changes have consequences for the growth, survival and abundance of species, including those of commercial importance or critical to conservation objectives.

At present, most of these impacts are assessed at scales greater than marine regions. The Community Temperature Index combines species temperature affinity and their abundances. This index has the potential to inform how communities change due to climate change. An example of changes in the Community Temperature Index from bottom-living fishes can be found in the Fish section within Biological Impacts of Climate Change, where more information on other impacts in marine food webs can be found (such as seabirds and marine mammals) on large regional scales in Scottish waters.

Sea surface temperature in the Moray Firth region has increased since 1870 by 0.05 °C per decade on average.  The rate of increase has not been constant, and in the last 30 years (1988-2017), the rate of change in temperature was +0.23 °C per decade.

Tide gauge records from around Scotland’s coast show a high degree of year-to-year change in coastal water levels (typically several centimetres). The long-term average mean sea-level change in the Moray Firth region, as estimated from a historical climate model run (UKCP18), was 5 cm (likely range between 2 and 8 cm) higher in 2018 than the 1981-2000 average. For reference, the Scottish average is estimated to be 5 cm (likely range between 3 and 8 cm). By 2100, mean sea level rise in the Moray Firth region is anticipated to be approximately 38 cm for a medium emissions scenario (UKCP18 RCP4.5; see also and Climate change Sea level assessment).

Offshore renewable energy is an important component in respect of reducing emissions of greenhouse gases.  In 2018 the total installed wind capacity in the Moray Firth SMR was 273 MW.

Summary

The Moray Firth SMR contains a number of freight ports which have seen an 83% decrease in freight tonnage over the five years between 2014-2018.  There are a number of small fishing harbours that have seen a 13% increase in value of landings over the same period.  Ship building continues in MacDuff.  Marine tourism and recreation has increased with a 14% increase in GVA in the four years between 2014-2017, whilst rod and line caught salmon and sea trout decreased by 11% between 2014-2018.  Oil and gas production fell to zero over the period 2014-2018.  Other active sectors include renewables, military activity,  subsea cables and seaweed harvesting and cultivation.

The five main pressures affecting the SMR are Removal of target species, Removal of non-target species, Physical change, Surface / Sub-surface abrasion / penetration, and Underwater noise.  Other pressures identified are Introduction of non-indigenous species and litter.

Nutrient inputs to the Moray Firth SMR are some of the highest of any SMR although there is no evidence of eutrophication. Contaminant (i.e. PAHs, PCBs, PBDEs and heavy metals) concentrations are generally above background but below levels that might cause adverse biological effects.  Heavy metal inputs were some of the highest across Scotland and there is an increasing trend in mercury inputs.  Concentrations of TBT overall are not causing significant harm except at one site where TBT was at an unacceptable level. Litter and microplastics are present with no consistent trend and microplastics in surface water occur at relatively low concentrations.  There is some evidence of an improving situation in relation to most beach litter categories except those related to marine industries (i.e. shipping and fisheries).  There are few noise data, but noise levels are expected to rise as wind farm developments progress.  No bathing waters were classified as Poor.

Two new MPAs were designated between 2012-2018, and one new spatial management measure was put in place.  Spatial management measures were under discussion for a further three.  (Note that in December 2020, two more MPAs were put in place.)  Subtidal biogenic habitats were assessed as ‘some concerns’, with 57% of the seafloor predicted to have been subject to high physical disturbance and 9% subject to none.  There have been improvements in the knowledge of several seabed habitats including burrowed mud, seagrass beds and horse mussel beds.   

In the last 30 years sea temperature has risen by 0.23 °C per decade.  Sea level in 2018 is estimated 5cm higher than the 1981-2000 average.