The spiky Spiny Starfish can grow up to 70 cm but this one, spotted in Mount’s Bay on a kayaking trip, was a more modest 20 cm.
Photo: Steve Townsend

Scientific name: Marthasterias glacialis

What to look for:

• Colouring and appearance: Five arms, each with three rows of white spines tipped with purple. The body is variable, from pale grey to brownish, sometimes tinged with green.
• Size: Up to 70 cm across, but more commonly 25 to 30 cm.
• Where: Eastern Atlantic; in the UK, on western coasts.

The Spiny Starfish might look attractive, with its pale, purple-tipped spines, greyish-greenish body and five-limbed elegance, but it is a fearsome predator. As well as molluscs, it will even feed on other starfish. Look closely, and you will see that its protective spines are surrounded by further tiny spines. These are called pedicellariae which, as well as providing additional protection, are used in gathering food.

Did you know…?

…The Spiny Starfish is the only species in the genus Marthasterias (i.e. the genus is ‘monotypic’).

…There are about 1,500 starfish species globally, some 30 of which you can spot round the British coastline.

…Did you know that starfish can regrow an arm if they lose one? They sometimes deliberately shed an arm if it is injured, or to escape a predator’s grasp.

Published: December 2016
Author: Amanda Scott
Photos: Steve Townsend