Serrated wrack, Fucus serratus, is easily recognized by its serrated edges. In the Baltic Sea we can find serrated wrack along the Swedish coast up to the Gryt archipelago in Östergötland, where the salinity is approximately 7 psu. We have not found any observations of its distribution along any other Baltic countries coastlines. If you know of any such, please let us know.

Serrated wrack (Fucus serratus) on the Swedish coast

Serrated wrack is sensitive to dehydration and is not as tolerant as i.e. bladderwrack to air exposure. Where we find baldderwrack and serrated wrack living together, the serrated wrack is often found slightly deeper thatn the bladderwrack. Outside the east coasts of Öland and Gotland, for example, there are wonderful forrests of serrated wrack at about 8 m depth.

Serrated wrack thrown ashore by waves often gets a more brown-orange colour before it dries and turns almost black.
In the winter, you can find frost covered seaweed when you walk along the shore.

Frozen Fucus serratus

More information will follow.