Take a walk on the beach and gather stones and mussel shells that have floated ashore. Do you recognize three of our most common mussels and how they live?
Baltic clam or Baltic macoma,Macoma Balthica
Finding the softly triangular shell of the Baltic clam on the sand bottoms is easy. They are white, sometimes slightly yellow or pink. The mussel lives dug down 3-8 cm into the soft sea beds. It lies on its side and has two air tubes or siphons, sticking out of the sea bed. The Baltic clam can grow about 2.5 cm large and live for 5-10 years.
Blue mussel or Sea mussel,Mytilus edulis
Blue mussels or sea mussels eat phytoplankton. A small mussel can filtrate several litres of water an hour, and together they are calculated to filtrate the water volume of the whole of the Baltic at least once a year. In the Baltic the blue mussel only grows to about 5 cm in size. It is an important food for flounders and eider ducks.
Soft-shell clams or Sand gaper,Mya arenaria
When you wade on a shallow sand bottom you can see soft pipes, the size of fingers, sticking out from the sand. It may be the air tubes of soft-shell clams or sand gapers. They live dug down into the soft sea beds. When a sand gaper has dug itself down, it basically stays put for the rest of its life. It can grow to about 5 cm in size.
Sea eagle, Haliaeetus albicilla
The sea eagle can be spotted flying over the town of Hanko daily. It is the largest of all daytime birds of prey in northern Europe. Its wingspan can reach up to 2.5 metres. The sea eagle mainly feeds on fish and other birds.
Common eider duck, Somateria mollissimma
The eider duck is one of the most common birds in our archipelago. It feeds nearly exclusively on blue mussels.
Oystercatcher, Haematopus ostralegus
The Oystercatcher has got a bright red beak, pink legs and red eyes. They are loud birds, which is possibly their most distinguishing feature. The Oystercatcher eats worms, but with the help of its strong beak it can also eat mussels and molluscs. The Oystercatcher is the official bird of Hanko.
Flounder, Platichthys flesus
The flounder spends the largest part of its life lying on its one side on the sea bed. It is difficult to detect, since it camouflages itself and changes colour to match the colour of the sea bed. The flounder eats blue mussels and Baltic clams in particular.
Grey seal, Halichoerus grypus
With a little bit of luck you can spot the grey seal in Hanko daily, as there are over 12 000 grey seals in the Baltic. They are particularly common in the outer archipelago. In comparison to the ringed seal the grey seal has got a longer nose and no angle between its forehead and its nose.
Moon jellyfish or common jellyfish, Aurelia aurita
The moon jellyfish is particularly common by the beaches in the autumn. A distinguishing feature is the four pale pink or slightly yellow sexual organs in the center of the jellyfish, which look like ears or rings. The moon jellyfish feeds on zooplankton and fry and is limited to using its whole body when gathering food. It uses its tentacles to kill or stun its prey. In the Baltic the moon jellyfish is 5-20 cm in diameter. It is harmless to humans.