Supporting our Seas

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Coolstays supported the restoration of approx. 584 sq m of native oysters in the Solent in 2023

Coolstays has chosen to support native oyster restoration in the Solent (the strait that separates the Isle of Wight from mainland England) in partnership with GreenTheUK and the Blue Marine Foundation.

Native oysters are classified as a priority species in the UK’s Biodiversity Action Plan and restoration is a high priority at the national, European and global level. An estimated 85 percent of oyster beds and oyster reef habitats have been lost worldwide, making them among the most imperilled marine habitats. As ecosystem engineers, oysters provide a range of benefits to the environment and local communities:

  • They improve water quality: a single oyster can filter 200 litres of water every day
  • They provide habitat to thousands of other species: fish and marine life
  • They are a natural defence to coastal erosion
  • They were a valuable food source (with evidence dating back to the Roman Times in the UK), yet this benefit has been lost due to their more recent dwindling numbers in the Solent

Coolstays has helped support the restoration of oyster reefs in areas protected from fishing to help re-establish wild populations. This work is in collaboration with the university of Portsmouth, where we have deployed adult oysters in the Solent on to newly formed reefs to significantly scale the restoration work. The aim of the project is to actively restore 4 hectares of oysters. Over two years, Coolstays has supported the restoration of approximately 584 square metres of native oysters. Find out more about the project below.

Project Overview

The Solent Oyster Restoration Project is part of a wider project called the Solent Seascape Project which aims to reconnect the Solent into a functioning seascape by improving the condition, extent, and connectivity of key marine and coastal habitats, using protection and restoration initiatives.

The Solent Seascape Project is the first of its kind in the UK to initiate seascape scale recovery. Our long-term vision is to protect and restore at least 30 percent of the Solent’s seascape, tipping the balance from a degraded state to a naturally expanding, connected and productive ecosystem. By restoring and connecting the Solent’s seascape, we will provide nature-based solutions to many of the issues currently affecting it and the people who depend on it, as well as helping to fight the impacts of climate change.

Oyster restoration has begun in the Solent, marking the start of the wildly ambitious five-year Solent Seascape Project which plans to restore marine habitats across the region.

Working closely with the River Hamble Harbour Authority and local contractors Jenkins Marine, Blue Marine finished laying the foundations for the largest oyster restoration reef in the Solent on 31 March 2023. A mixture of shingle and cockleshell, known as ‘cultch’, has been placed over 2,500 square metres of seabed in the River Hamble and will provide a home for 15,000 oysters to attach and grow in the coming weeks.

“After a year of logistical planning we carefully laid 468 tons of cultch on the seabed of one of the UK’s busiest waterways to form the foundation of our largest oyster restoration reef in the Solent. Seeing this project eventually come to fruition was such a proud moment for the whole Solent team as well as the contractors and regulators we have worked with to reach this milestone. Together we have done something amazing for nature.” said Louise MacCallum, Solent Project Manager at Blue Marine.

More than 150 volunteers assisted with the huge job of putting 14,939 native oysters – Ostrea edulis – through a stringent biosecurity process before they could be deployed on the new reef in the River Hamble. These oysters were sourced from an oyster farm in Pembrokeshire, South Wales.

Blue Marine Foundation’s Ambassador, HRH Princess Eugenie, visited the Solent Seascape Project for two days during April to help us with putting oysters through our biosecurity process and meet project partners for high tea at the top of the Spinnaker Tower, overlooking the entire seascape. The royal visit was covered exclusively by Hello! Magazine:

Plans are progressing to create our next oyster reefs in Chichester and Langstone Harbours. Partnership work like this project has begun to drive forward multi-habitat, seascape scale restoration across the Solent region, with baseline monitoring of new saltmarsh and oyster restoration sites in Chichester Harbour, River Hamble and the Isle of Wight underway.

UN's Sustainable Development Goals

As a GreenTheUK partner, you support projects that are in line with the UN Sustainable Development Goals.

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Take urgent action to combat climate change and its impacts.

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Conserve and sustainably use the oceans, seas and marine resources for sustainable development.

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Species this project aims to support

Native Oyster: Ostrea Edulis

Native Oyster

These molluscs live on the seabed in estuaries and shallow coastal waters where there is a lot of mud and rock. Also known as the European flat oysters, they have been fished from UK waters since Roman times when they first became a popular delicacy. The Romans even used to transport them back to Italy, where they got their reputation as an aphrodisiac.

Undulate Ray: Raja Undulata

Undulate Ray

Undulate rays like soft seabeds so that they can burrow underneath the sand or mud. This ray has an almost pointed head, leading to a rounded body and straight tail, and is named after the distinctive wavy pattern on its back. Undulate rays are classed as an endangered species because of overfishing.

Starry Smooth-hound: Mustelus Asterias

Starry Smooth-hound

This shallow-water species of shark has white dots scattered around its fin and tail. It feeds on small fish, crabs, prawns and lobsters and can be found in the UK’s coastal waters as well as in the River Thames. The starry smooth-hound has two dorsal fins; the front fin is slightly larger than the one at the back.

Spiny Seahorse: Hippocampus Guttulatus

Spiny Seahorse

Also known as the long-snouted seahorse, this creature can be found in shallow waters along the south coast of England and Wales. Seahorses deal with pregnancy in a different way from every other species, because the males give birth! Female seahorses transfer their eggs to males who then self-fertilise them, carry and birth their live young.

European Eel: Anguilla Anguilla

European Eel

Once common, the European eel is now a critically endangered species. The number of European eels is believed to have dropped by over 90 percent in recent years, and the race is on to save this remarkable creature from extinction. They are nocturnal and can live for up to 85 years, but nobody has ever witnessed an entire European eel life cycle.

Sea Bass: Serranidae

Sea Bass

There are around 475 species of sea bass, most of which favour warm, shallow waters. They are carnivorous, existing on a diet of smaller fish, molluscs, crustaceans and invertebrates. Sea basses come in all shapes and sizes, from the tiny ones measuring a few centimetres, to two-metre-long whoppers!

Thresher Shark: Alopius Vulpinus

Thresher Shark

The thresher shark spends most of its time in deep water far out to sea, but occasionally passes by the UK’s coast in the summer months. It can control its body temperature very effectively, keeping it higher than the cold water around it. The thresher shark uses its long tail to round up its prey, before thrashing, killing, and eating it.

King Scallop: Pecten Maximus

King Scallop

Scallops have between 50 and 100 eyes, allowing them to detect changes in light. They can live for over 20 years and develop growth rings, just like trees, enabling us to age them. Scallops can open and close their shells, producing jets which power them through the water, allowing them to effectively swim short distances from predators.

Cockle: Cerastoderma Edule


Cockles are found all around the UK’s coastline, on muddy, sandy seashores and in estuaries. Cockleshells can close completely so that there is no gap around the edge. Cockles aren’t just a popular seaside snack for humans; they also make up an important part of many shorebirds’ diets.

Cuttlefish: Sepia Officinalis


This remarkable creature can change texture and colour either to attract a mate or to help them blend into the background and fool predators. Like its squid and octopus relatives, the cuttlefish is a cephalopod with eight sucker-covered arms and two tentacles. Cuttlefish live in deep water, then move into more shallow areas to mate, and tend to die after they have bred.

Sand Eel: Ammodytes Tobianus

Sand Eel

Sand eels make up a crucial part of the diet of many species of marine life and seabirds in particular. As the name suggests, they prefer living in sandy areas, and burrow down into the sand to escape predators. Their eggs are tacky so that they can stick to the seabed, before hatching a few weeks later.

Herring: Clupeidae


There are around 200 species of herring, but only three of them are generally caught for food. Herring travel together in large schools, feeding on plankton at night. Herring is a very oily fish that is rich in nutrients, making it a popular snack in many parts of the world, notably Scandinavia.

Common Seal: Phoca Vitulina

Common Seal

The harbour or common seal is both smaller than the grey seal and less prevalent in UK waters. This seal’s blood contains much more haemoglobin than ours, allowing it to stay underwater for around 10 minutes at a time when diving after prey. Seal pups can swim and dive when they are just a few hours old.

European Eel: Anguilla Anguilla

European Eel

Once common, the European eel is now a critically endangered species.The number of European eels is believed to have dropped by over 90 per cent in recent years, and the race is on to save this remarkable creature from extinction.

Grey Seal: Halichoerus Grypus

Grey Seal

Just under half of the grey seals in the world can be found in British coastal waters. Pups are quite small at birth but put on weight quickly as they develop blubber to help them deal with the cold. Their Latin name means “hook-nosed sea pig”.

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