The ‘Disco Doris’ sea slug (Gargamella rosi) was first seen in the UK in 2008. Since then, it has been spreading gradually in the southwest, and this year has become very common at times in Cornwall, with its stunning orange colour and circular markings.

The rainbow sea slug (Babakina anadoni) is an incredibly colourful nudibranch that is a new arrival to UK shores. It has spread quickly in parts of Cornwall, and is becoming a more regular sight in the rock pools and deeper water: a great subject for underwater photography and filming.