Cornwall seascape, Sam Mansfield

24 reasons why UK seas are important

6 minute read

The UK’s coastline is over 22,000 miles long, with far-ranging climates and geologies, home to a vast array of habitats and wildlife. We explore 24 reasons why UK seas are globally important.

Britain and Ireland are some of the most nature-depleted countries in the world. In 2024, we’re working to turn the tide on nature loss. If you’d like to help us protect and restore our seas, you can donate £24 or as much as you can afford.

1.The Gulf Stream

The Gulf Stream is a big contributor to the richness of UK seas, bringing warm water and with it, extreme weather. This extreme weather causes unsettled seas, where waves churn the water and cycle nutrients to the sea’s surface, allowing for marine wildlife to flourish.

2. Tides

In some places, there’s a 40 metre difference between high and low tide; the Severn Estuary has the second highest tidal range in the world while Oban in Scotland is home to the third largest whirlpool on the planet. Powerful whirlpools, driven by strong tides, churn up and mix the water, cycling nutrients, making UK seas valuable feeding grounds for many species.

3. Seasonal hosts

The UK’s position on the globe is perfect for summer visitors from the south and winter visitors from the north, with temperatures ranging from arctic conditions on the top of the Cairngorms in Scotland, to subtropical in the far south. Leatherback turtles and humpback whales regularly grace our shores during summer, and walruses have been occasionally spotted during the winter!

4. Britain’s Great Barrier Reef

The Norfolk coast is home to the longest chalk reef in Europe, possibly the world: the Cromer Shoal Chalk Beds.

At over 20 miles long, the 100-million-year-old reef supports a unique array of plants and animals. The reef is composed of towering arches and deep chasms made during the Ice Age.

Sponge crab Cromer Shoal Chalk Beds MCZ, Norfolk, Samantha Bean.jpg

Credit: Samantha Bean

5. Artistic inspiration

Throughout the ages, artists have visited and lived beside the UK’s coastline, inspired by its ever-changing beauty and drama. J. M. W. Turner is one of the UK's most famous seascape artists, spending his entire life capturing the character of the sea and life on the British coast. The Turner Contemporary, an art gallery in Margate, Kent, commemorates the association of the town with the noted landscape painter.

6. Island nations

In the UK, no-one lives more than 80 miles from the sea. Those living the furthest from the sea reside in Coton in the Elms, in Derbyshire. Many traditions and unique cultures are borne from communities living beside and with, the UK ocean and coast.

7. World class diving

Hundreds of years of merchant seafaring have left a rich wreck heritage.

With huge tidal ranges, adrenaline-pumping drift dives and wildlife ranging from tiny seahorses to gigantic basking sharks, diving on your doorstep in the UK offers a unique experience.

Ingrid Seasearch - Ben Lamming

Credit: Ben Lamming

8. Grey seals

Blakeney Point in Norfolk is well-known for its seal population, which is the biggest seal colony in England. More than 40% of the world’s population of grey seals are found in the UK, making our seas globally important for the species. In November and December seals come ashore to pup, give birth and rear young, this puts them at increased risk from pollution and entanglement. Our beach cleaning ensures a clean and pollution-free environment.

9. Seagrass

The UK’s seagrass meadows are home to two species of seahorse: spiny and short-snouted. Seagrass meadows are also vital in capturing and storing carbon, much like forests on land. In fact, they’re estimated to absorb and store 35 times more CO2 than rainforests. Many UK seagrass beds - an estimated 92% - have been lost or damaged in the past century.

10. Seabirds

In Wales, Skomer Island is designated for its globally important seabird population. In Scotland, each year 75,000 pairs of gannets arrive on Bass Rock to nest, forming the biggest colony of northern gannets in the world. The UK is also home to 80% of the breeding population of Manx Shearwaters, one of the longest-lived UK birds, with a record of living to be 55 years old.

11. Otters

In Shetland, there are around 800-1,000 otters – the highest density of otters in Europe. One of 13 species in the family group, the Eurasian otters in Shetland are the same as can be found elsewhere across the continent, .

12. Parpal Dumplin’

A completely new species of sponge was first discovered more than 10 years ago by Seasearch divers, living in the North Norfolk chalk beds. The sponge had remained nameless until a Norfolk school girl’s suggestion was chosen. Expert judges unanimously agreed the sponge should be named Parpal Dumplin’ – a name that evokes the sounds of the Norfolk accent. 

13. Newly discovered nudibranchs

Seasearch diver Libby Keatley was diving off the coast of County Antrim in Northern Ireland when she spotted something unusual. The sea slug - or nudibranch – whose transparent body had orange lines running through it and twiggy projections arranged along its back was later confirmed as a new species and named in Keatley’s honour: Dendronotus keatleyae.

14. Maerl

Maerl beds, though rare in the UK, are incredibly rich in marine life. Their lattice structures are perfect for life to grow on and within. Maerl beds can be found in the Fal estuary in England which, researchers have found, is genetically distinct from maerl in other areas.

Hermit Crab on Maerl Georgie Bull

Hermit crab on maerl

Credit: Georgie Bull

15. Gentle giants

The world’s second-largest fish, the basking shark, arrives in UK seas during the summer months to feast on plankton-rich waters. Commonly spotted in Scottish seas, the gentle giants are the largest fish to visit the UK. There remains much mystery around the species’ breeding habits, but researchers believe that the deep waters of the Sea of Hebrides may play a part.

16. The English Channel

The busiest sea route in the world, more than 500 ships pass through the Channel daily. The Dover Strait is the busiest shipping lane in the world. Ever since 1875, swimming the English Channel has been seen as an athletic feat and is arguably one of the world's most historically significant and iconic marathon swims.

17. Bottlenose dolphins

Cardigan Bay in Wales is home to Europe's largest population of bottlenose dolphins, while the Moray Firth in Scotland is home to the most northerly population in the world. It’s highly likely when visiting the UK’s coast that you’ll be able to spot some of these frequent visitors to our shores!

18. Seas of value

From supplying coastal flood defences and locking in carbon, to tourism and fishing, the economic value of our seas and coastal habitats is extraordinary. The Office for National Statistics values the UK’s marine natural capital assets at £211 billion.

Our study found that, if damaging activities were banned in England’s offshore Marine Protected Areas, the overall net benefit could amount to between £2.57 billion and £3.5 billion over a 20-year period.

19. A major tourist destination

The tourism industry alone accounts for the employment of 250,000 people across 150 seaside resorts, and contributes £4 billion to the UK economy. 10% of all international visitors that arrive in UK go to the coast, with South East England being the most popular. The coast is also a very popular domestic tourism destination due to the plethora of seaside activities available to the public.

Coast path in Cornwall Natasha Ewins

Credit: Natasha Ewins

20. A journey back in time

Now recognised as a UNESCO World Heritage Site, the Jurassic Coast is the only place on Earth where rocks from the Triassic, Jurassic and Cretaceous Periods can be seen in one place, representing 185 million years of the Earth's history. In Dover, the chalk cliffs have one of the most accessible and complete records of the story of chalk formation, made from layers of soft, white, finely grained limestone, which have built up over millions of years.

21. Shaped by nature

From Durdle Door to the Giant’s Causeway, the Old Man of Hoy to the Green Bridge of Wales, and many spectacular coastal wonders in between, the ocean has shaped the coastline of the UK and Ireland. Formed through centuries of coastal erosion, many of these sights are at risk of being lost forever as rising sea levels and extreme weather batter the UK’s coastline.

22. A desert in Kent

While the myth was officially debunked by the Met Office in 2015, Dungeness in Kent is still a remarkable location. The stony landscape is so barren, and receives little rainfall, resulting in the coastal location being dubbed the UK’s only desert.

23. Remarkable beaches

Britain has more than 6,000 islands, and Lewis and Harris in the Outer Hebrides, with deserted beaches and turquoise shallows, could be mistaken for beaches in more exotic climes. The rolling dunes of Harlech beach in Gwynedd have made the destination a National Nature Reserve and Site of Special Scientific Interest, with dramatic vistas to enjoy. The 18 miles of shingle at Chesil stretches from West Bay to Portland, and is one of Dorset's most iconic landmarks. These beautiful beaches all play a part in showcasing how special our coasts are.

Sandy beach and clear sea at Seilebost on the isle of Harris in the Western isles of Scotland Helen Hotson

Sandy beach on the Isle of Harris

Credit: Helen Hotson via Shutterstock

24. Victorian-era ‘pleasure piers’

These iconic structures are unique to the British seaside. In their heyday, piers on the British seaside would provide holidaymakers with entertainment, with grand pavilions and theatres atop the sea. However, almost half of of the nearly 100 piers gracing the UK coastline have now gone. These piers are not only a link to our Nation's past but also have become areas that are home to local marine wildlife which provide safety and shelter for crabs and invertebrates.

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24 for the Ocean