Rare rainbow sea slug found at Devon beach by school student

A rainbow sea slug was found in Devon. Credit: Barefoot Photographer/Nikki Banfield

Sea slugs making a home in the UK due to climate change are among the species spotted around the country’s coasts in 2024, The Wildlife Trusts said.

Species recorded on the UK’s coasts in 2024 included “climate indicators” such as the first record of a rainbow sea slug in Devon, found by a school student on a family day trip to Wembury Beach.

Sea slugs are normally found in warmer waters and have only been recorded in UK waters in the past couple of years, suggesting they are moving due to climate change.

Hundreds of mauve jellyfish, normally found in warmer waters such as the Mediterranean, washed up in Cornwall and on the Isles of Scilly – possibly due to weather conditions.

Hundreds of mauve coloured jellyfish washed up in Cornwall and on the Isles of Scilly. Credit: Barefoot Photographer / Nikki Banfield

Monitoring also uncovered non-native species that could affect British wildlife, including pom-pom weed - an Asian-native seaweed that could displace barnacles - in Devon. 

A very dense collection of invasive Pacific oysters, which can alter ecosystems and displace native oysters, was logged at Hope Cove in Devon.

Among other notable wildlife sightings in UK waters were 30 humpback whales recorded off Cornwall last winter, including Ivy who was freed from entanglement by lifeboat crews.

A rarely seen 'sea mouse' worm, normally found on the seabed, was seen moving through the Cornish sands at high tide, too.

Ruth Williams, head of marine conservation at The Wildlife Trusts, said: “Wildlife surveys and monitoring have led to incredible discoveries, including new species on UK shores.”