Scotland's future catching policy: strategic environmental assessment report 2026

4. Environmental Baseline

4.1 Summary of the Environmental Baseline

Section 4 provides a summary of the current state of the UK marine environment for each of the environmental issues screened into this SA, and where applicable their associated UK MS descriptors (Table 1). The SA has been conducted against the environmental baseline set out in these sources of existing information. We acknowledge that there are some uncertainties and evidence gaps in the environmental baseline. However, we consider that this environmental baseline provides a comprehensive level of information to undertake an effective assessment. Where required, further detailed assessments using additional evidence will be completed ahead of the implementation of selectivity proposals.

Addressing selectivity in fishing practices is essential for sustainable fisheries. Reducing levels of unwanted catch, and therefore discarding, and bycatch of sensitive marine species has the potential to support improvements to the current state of the environment set out below, both where no improvement has been observed, and where positive trends have been identified. Section 6 and 7 considers how the implementation of the selectivity proposals could support changes to the baseline.

4.2 Biodiversity, Flora, Fauna

The primary source of information on the current state of the UK marine environment came from the UK MS descriptor status assessments, The updated UK Marine Strategy Part 1, published in 2019. The impact of fishing has been considered as part of the assessment on the UK MS descriptors, therefore information on the impact of fishing activity on the marine environment has been included in the sections below as part of the baseline. For further information on the baseline related to UK MS descriptors see Appendix B.

D1 and D4 – Fish and D3 – Commercially exploited fish and shellfish

Fish are an important ecosystem component that contributes to overall levels of biodiversity (D1). In addition, fish of different species have a significant role in marine food webs (D4), acting as both predators and prey. Some fish species are commercially exploited, and only a proportion of these have managed quotas. Over exploitation can lead to a decline in stocks (D3) which can reduce both future commercial opportunities and have wider ecological impacts.

The current status of fish communities in the UK is primarily shaped by historical over-exploitation by fisheries, while ongoing over-exploitation continues to be a notable contributing factor. Improved fisheries management since the 1990s has resulted in more stocks being fished at or below MSY levels, so although the target is not yet met there is a positive trend. Improved fisheries management has also resulted in some positive trends in fish communities beyond the targeted stocks.

Sampling programmes are used to make annual assessments of the quantity and composition of the demersal catch. The catch is divided into the landings and bycatch (unwanted catch) components. The Scottish Demersal Observer Programme, operated jointly by the Marine Directorate of the Scottish Government and the Scottish Fisherman's Federation, collects biological data from the bycatch of these trawler fleets targeting demersal species in the North Sea and the West of Scotland. Since the implementation of the landing obligation discarding figures have decreased, however discarding of unwanted catch at sea still remains a very real issue as can be seen from the discard estimate data set for 2024 in Table 2 (Appendix C) and report (Appendix D).

D1 and D4 – Birds

Seabirds are well monitored species that are an important marine ecosystem component that contributes to overall biodiversity (D1). In addition, as top predators, the abundance of birds can also provide some understanding and insight as to how the wider food web is functioning (D4).

Seabird populations are currently below the level that is considered to meet GES and the situation is deteriorating. Some declines in breeding success have been linked to prey availability caused by climate change and/or past and present fisheries. Invasive predatory mammals are also known to impact breeding success on island colonies. Bycatch is also an ongoing pressure,on seabirds and current evidence suggests that some longline and static net fisheries could be having possible population level impacts on certain species.

D1 and D4 – Cetaceans

Cetaceans (whales and dolphins) are an important marine ecosystem component that contributes to overall levels of biodiversity (D1). In addition, as top predators, the abundance of cetaceans can also provide some understanding on how the food web is functioning (D4).

Other than for a limited number of coastal bottlenose dolphin populations, it is unclear whether the abundance and range of most cetacean species can be considered in line with GES. Fisheries and the removal of prey species and bycatch of cetaceans is one of several activities/pressures that have the potential to result in changes to cetacean abundance and distribution.

D1 and D4 – Seals

Seals are an important marine ecosystem component that contributes to overall levels of biodiversity (D1). In addition, as top predators, seal productivity can also provide some understanding and insight as to how the food web is functioning (D4).

Grey seal populations and productivity continues to increase, and targets are being met. Bycatch (largely in tangle/ trammel nets) is occurring but not at levels that threaten population viability. For harbour seals, the status is not in line with GES where population declines have occurred in some areas. The cause is unknown. It is not thought to be linked to bycatch as occurrences are rare and there is no indication that it is linked to other pressures associated with fishing.

D4 – Food webs

Food webs (D4) are the network of predator-prey relationships that occur in the marine environment, from phytoplankton to top predators such as birds or seals. Fish communities are a key component of food webs. Knowledge of food webs allows understanding of how changes at one trophic level can impact those above and below it.

Historic fishing activity which has contributed to the current environmental baseline has had a large impact on fish community structure which is a key component of marine food webs. With improved fisheries management focusing on stocks, some recovery is occurring. However, the management of fish stocks solely to safeguard future fisheries will not necessarily lead to all food web targets being met. Changes in plankton are likely driven by prevailing environmental conditions, but other impacts cannot be ruled out.

D10 – Marine Litter

Marine litter, including from fishing activities, is a significant pressure on marine ecosystems and water quality. The UK has not yet achieved its aim of GES for litter. Beach litter levels in the Greater North Sea have increased slightly since the assessment in 2012. Waste fishing material is a component of beach litter. Both floating litter and seafloor litter remain an issue, with plastic the predominant material. Achieving GES for marine litter requires improved waste management practices, the reduction of lost or discarded fishing gear and increased awareness and monitoring of the issue.

4.3 Climatic factors

Climate change impacts are not part of the UK MS, therefore evidence from other sources was used to provide baseline information in relation to this issue. Statistics from the Department for Energy Security and Net Zero (DESNZ) (formally known as Department for Business, Energy & Industrial Strategy (BEIS)), Department for Transport (DFT) and Engelhard et al (2022) report on Carbon emissions in UK fisheries, were used to identify the contribution UK fishing fleets have to the total carbon emissions at sea each year.

4.4 Vessel Emissions

For 2019, estimated emissions by the UK fishing fleet (802 kt CO₂e) would have represented 0.18% of the UK’s total territorial emissions (455 Mt CO₂e) ^[5], or 0.66% of the UK’s domestic transport emissions (122 Mt CO₂e)^[6]. To put this into context, estimated emissions by the UK fishing fleet would have been equivalent to 1.7% of total agricultural emissions in 2019 (46.3 Mt CO₂e).

Recent analysis has shown that the total UK fishing fleet segment using demersal trawls and seines, which comprises of 402 vessels, produced approximately 30% (249kt CO₂e) of the total carbon emissions at sea each year across the UK’s fishing fleets. Drift and fixed net fisheries (237 vessels) produced approximately <2% (13kt CO₂e). Whilst passive gears are generally less emission-intensive than mobile gears, quantification of carbon emissions across the fishing fleet supply chain (for example, preharvest through to postharvest) is required to truly understand the fisheries carbon footprint.

4.5 Climate change impacts on demersal stocks and fisheries

Climate change and warming oceans are changing the distribution and fish assemblages of commercially important species^[7]. Most demersal/whitefish species are expected to move northward in response to climate change with northwest European waters expected to be less suitable for key commercial species such as cod, haddock and saithe^[8]. As ocean temperatures rise, suitable spawning areas for most demersal species are expected to shift poleward to cooler waters.