Marine Protected Area network: 2024 report to the Scottish Parliament

3. Scotland's seas

Scotland's seas are some of the most biologically diverse in Europe, supporting thousands of species across a wide variety of habitats.

Positioned on the north-west edge of the European continental shelf, Scotland's seas see the meeting and mixing of nutrient-rich waters which provide the perfect home for sea life to thrive.

Our coastlines are home to a range of different animal species including marine birds, such as the iconic puffin, and marine mammals, such as seals. These, and other species, are supported by a complex array of diverse and productive habitats such as kelp forests, seagrass meadows and maerl beds.

Further out to sea can be found large sediment plains made up of sands, gravels, and burrowed mud. These also support a wide range of marine life, including sandeels, a cornerstone of Scotland's marine ecosystem; and the ocean quahog, a species of clam which can live for centuries.

Evidence of Scotland's rich past can also be found in our seas in the form of shipwrecks, aircraft and artefacts from submerged pre-historic landscapes. This wealth of underwater cultural heritage allows us to understand the important role that the sea has played in Scottish history.

Beyond providing a haven for wildlife or a source for understanding Scotland's past, our seas also provide a range of benefits for Scotland's people, industries and communities.

The sea remains an important source of food, with Scotland's fishing and aquaculture industries relying on a healthy and thriving marine environment. Offshore energy generation is also vital in enabling Scotland to meet our net zero targets and contribute to addressing climate change. Marine recreation and tourism is also an increasingly important part of our marine economy, with people travelling from all over the world to enjoy Scotland's wildlife.

In total, in 2021, the Scottish marine economy generated £4.5 billion in GVA, which accounted for 3% of the total Scottish economy. It also provided employment for 69,800 people, which was 2.7% of the total Scottish employment.^[2] The marine tourism sector had the highest employment of all marine sectors with 28,600 people.

Some of the benefits we get from healthy seas are less tangible, such as nutrient cycling or helping sustain well-being through our physical and mental health ('the natural health service'). Our seas also have a key role to play in climate regulation as part of the global ocean life support system. The ocean produces 50% of the world's oxygen, absorbs 25% of human-caused carbon dioxide emissions and 90% of the excess heat created by human-caused greenhouse gases.^[3]

Scotland's seas, however, are facing increased pressures in the face of the twin crises of climate change and biodiversity loss.

For example, Scotland's Marine Assessment 2020 found that nine out of 21 marine regions have seafloor habitats which are predicted to be in poor condition across more than half of their area. The assessment also identified multiple factors affecting biogenic habitats including coastal

infrastructure, demersal fishing, aquaculture, vessel moorings and pollution, set within the context of long-term natural cycles.

While the status of some species, such as grey seals and bottlenose dolphins continues to improve, others have been declining. Seabird species in particular have been significantly declining in recent years, with 17 of 24 breeding seabirds showing a decline of 10% or more between the last two seabird censuses (1998 to 2021). Adding to this decline for some species was the subsequent emergence of highly pathogenic avian influenza (HPAI) which was especially prevalent in 2022 and 2023 and has now been recorded in the majority of seabird species. Gannets and great skuas, two of the species that had previously shown an increase between censuses, were particularly negatively impacted. Overall, Scotland's wintering waterbirds have decreased in abundance by 10% across the long-term term (1975-2020), with some of the 41 species assessed exhibiting range changes in response to environmental change. Marine birds are currently faced with a wide range of wide pressures including climate change, changes in food supply, fisheries bycatch, predation, pollution, disease, and on and offshore development.

Additionally, climate change impacts are already being observed in Scotland's seas and coasts; the rate and magnitude of these changes vary across Scotland. These include ocean acidification, temperature and sea level rises, increase in severe storm events, coastal erosion and loss of coastal protection, and changes to marine ecosystems. These climate change impacts amplify the impacts of other human impacts such as unsustainable fishing practices, plastic litter in our seas, and other forms of pollution.

Protecting our marine environment is vital for the viability of our marine industries and coastal communities, to halt the loss of biodiversity, to ensure our seas can continue to play a role in combatting human-caused climate change, and to ensure our seas continue to provide the benefits on which we all rely.