Cornwall Wildlife Trust says a number rare sightings in 2022 are a testament to how “spectacular life is below the waves”.
A number of Wildlife Trusts from across the UK have published their annual review, highlighting the diversity of the seas and coasts.
The discoveries this year include a 100-year-old Greenland shark washed up at Newlyn, Cornwall, and a rare colourful sea slug spotted off the coast of the Isles of Scilly - a first for UK waters.
Experts say the sightings of whales show how populations are recovering following bans on commercial whaling, after a humpback whale was spotted near Cornwall’s Lizard Peninsula.
In the summer, Cornwall Wildlife Trust reported huge numbers of octopuses around the Lizard Peninsula, which experts suggest is the sign of a healthy population and possible octopus boom – last recorded 70 years ago.
But a host of pressures are threatening the seas, from the global avian flu pandemic which has killed thousands of seabirds across the UK, to pollution including oil spills and plastic, as well as people irresponsibly disturbing wildlife.
Wildlife Trusts have also seen some good news for seabirds with the Isles of Scilly Wildlife Trust building almost 50 nest boxes for Manx shearwaters.
Dr Lissa Batey, head of marine conservation at the Wildlife Trusts, said: “From ancient sea creatures to new species for science, the discoveries in this year’s marine review show just how spectacular life is below the waves.
“While full of surprises, our oceans are also busy places where wildlife is facing a huge range of pressures – including climate change, pollution and development.
“The sea needs better protections to help nature recover and thrive as a matter of urgency.”
She added: “Protecting large areas of our oceans is crucial for fishing and other industries that rely on healthy seas, as well as providing security for important carbon storing habitats like seagrass meadows and seabed sediments.”