SPINY STARFISH

Spiny Starfish

Marthasterias glacialis

Size: Up to 70 cm in diameter.

Lifespan: Unknown.

Food: Omnivore, but the main food is snails and mussels.

Greedy predator that folds out its stomach

The spiny starfish is one of the largest starfish found in Swedish waters. It is a really greedy and voracious predator, eating just about anything that comes its way. Using its very strong suction feet, the starfish can easily pull apart the shell of a mussel, then “fold out” its stomach over and around the prey and slowly begin to break it down.

The spiny starfish is strong and uses its tube feet to open the shells of mussels.
Photo: Philippe-Guillaume-CC-BY

Lost arms can grow back

The starfish has really good healing powers and it is not at all uncommon for it to shed an arm and then grow it back again. It lives on both hard and soft bottoms, from a few metres to a few hundred metres deep, but it prefers to live where there is a good supply of mussels. It gets around using its many tube feet with small suction cups that it has on the underside of its body. See if you can find a starfish sitting on the window! See how the feet move and suck against the glass.

The colour of the spiny starfish can vary from brown to greenish-grey.
Photo: Peter-SouthwoodCC-BY-SA, Tato-GrassoCC-BY-SA, Asier-Sarasua-AranberriCC-BY-SA, Philippe-GuillaumeCC-BY

The spiny starfish has robust thorns on its arms.
Photo: Tato-Grasso-CC-BY

Distribution in Sweden

Bohuslän to
Öresund.

White marking = Distribution

Threat based on the Red List

Trade regulations

CITES: Not listed.