Appendix 5 – Pressures
Pressures are identified throughout the Healthy and Biologically Diverse chapter of the Solway Review. All of the pressures listed have the potential to cause negative impacts on the wider marine environment and ecosystem because of the interconnected nature of all aspects of the marine environment. No marine activity will only impact one element of the marine environment, there will always be knock-on or associated effects.
As with all marine spaces, pressures from human activities are a constant threat to the functioning of the Solway Firth. Socio-economic activities in the marine environment offer significant opportunities for humans, but have the capacity to damage or harm species, habitats and other aspects of the environment.
Marine litter and climate change are perhaps two of the most publicised and common pressures on the marine environment. Public awareness and knowledge of these pressure continues to grow and research and societal changes are ongoing to help mitigate and reduce these pressures across Scotland, the UK and beyond.
Several of the main pressures identified by Scotland’s Marine Assessment (2020) on the Solway Firth stem from the fishing activities which take place in the Firth. However, it is worth noting that the Solway is a lesser used portion of the UK marine area, with less frequency and risk of damage from many socio-economic activities. For example, underwater noise is included as one of the main pressures for the Solway marine environment, with shipping listed as the only main contributing activity to this pressure. Comparatively the Clyde Marine Region also has underwater noise assessed as one of the main pressures to the Clyde Marine Region, however there are several activities which contribute to this pressure; Aquaculture – Finfish, Military activities – Sea surface activity, Military activities – Sonar use, Shipping, Tourism & recreation (Moffat et al, 2020).
The main pressures on the Solway Marine Region listed in Scotland’s Marine Assessment (Moffat et al, 2020) (‘this pressure assessment used the Feature Activity Sensitivity Tool (FeAST) classification which includes two abrasion pressures: surface abrasion and sub-surface abrasion’) were;
1 – ‘Removal of target species (lethal): all species involved in recreational angling have been assumed to be ‘target’ species rather than ‘non-target’ bycatch. This activity is likely to be (mainly, though not exclusively) concentrated in inshore waters. Scallop dredging; creeling and potting; bottom otter trawling and pair trawls.’ This pressure may negatively impact commercial shellfish and fish stocks in addition to the wider marine food web and ecosystem.
2 – ‘Surface abrasion: this is mainly linked to impacts associated with yachts and other vessels anchoring away from marinas etc., scallop dredging and bottom otter trawling and pair trawls. Although there is also potentially some highly localised risk from SCUBA diving.’ Protected areas in the Solway Firth, as well as valuable habitats are affected by this pressure. Agitation of the seabed could affect benthic species and also release hazardous substances, remobilising contaminated sediments back into the water column.
3 – ‘Removal of non-target species: mainly linked to impacts of bottom otter trawling and pair trawls; recreational fishing; scallop dredging; intertidal fishing e.g. bait digging; creeling and potting.’ Removal of non-target species through by-catch can be harmful to the species removed whether or not the removal itself is lethal. Stress, and physical injuries may occur, which reduce the likelihood of survival in released species despite being returned to the marine environment. Seal and cetaceans are at particular risk, however fish (commercial/non-commercial/shellfish) in general are at risk from being caught despite not being targeted. There is also a risk that birds may be unintentionally harmed or killed through bycatch.
4 – ‘Sub-surface abrasion: this is mainly linked to impacts associated with trawling, and yachts and other vessels anchoring away from marinas.’ Protected areas in the Solway Firth, as well as valuable habitats are affected by this pressure. Agitation of the seabed could affect benthic species and also release hazardous substances, remobilising contaminated sediments back into the water column. In intertidal environments sub-surface abrasion can occur through bait digging.
5 – ‘Underwater noise: mainly driven by small boat activity. Noise footprint expected to be relatively local (small engines create higher-frequency sounds which get attenuated quicker). Significant numbers of larger vessel movements do not occur in this region.’ Continuous noise is more common than impulsive noise in the Solway, with vessel, harbour and recreational noise common within the Firth. Impulsive noise is less common due to the limited construction and offshore operation noise, comparative to other regions. However, there is still impulsive noise in the Solway affecting marine species, although with less density and frequency than in other regions. For example Multibeam Echosounder and Sidescan sonar survey work was being undertaken in the Solway Firth in July/August 2021. Marine mammals, fish, and invertebrate species are present in Solway Firth and can be negatively impacted through increased underwater noises in the Firth. As discussed in the noise section, there is a lack of data and estuary specific research on underwater noise in the Solway Firth.
Other pressures on the Solway listed in Scotland’s Marine Assessment;
- ‘Barrier to species movement
- Death or injury by collision below water
- Electromagnetic changes
- Hydrocarbon & PAH contamination. (Includes those priority substances listed in Annex II of Directive 2008/105/EC).
- Introduction or spread of non-indigenous species and translocations (competition)
- Organic enrichment
- Physical change (to another seabed type)
- Physical loss (to land or freshwater habitat)
- Synthetic compound contamination (inc. pesticides, antifoulants, pharmaceuticals). Includes those priority substances listed in Annex II of Directive 2008/105/EC.
- Visual disturbance (behaviour)
- Water flow (tidal current) changes – local’
(Moffat et al, 2020)
Moffat, C., Baxter, J., Berx, B., Bosley, K., Boulcott, P., Cox, M., Cruickshank, L., Gillham, K., Haynes, V., Roberts, A., Vaughan, D., & Webster, L. (Eds.). (2020). Scotland’s Marine Assessment 2020. Scottish Government. Available here. Direct link to Solway Pressures from Activities section available here. (Accessed: 10.04.21)
Image; Gull skull on Bathing House Bay, Knockbrex. © Solway Firth Partnership.