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For this Species Spotlight article, Peter Elbourne provides insight on dulse – known by scientists as Palmaria palmata. Dulse is perhaps the most famous edible seaweed native to the north Atlantic. Autumn is the peak of the harvest season for this species and that makes it the ideal time to share some of Horizon Seaweed’s insight on dulse.

Fundamentals of dulse biology

Dulse is one of the edible seaweeds traditionally eaten in coastal communities in northern Europe. While dulse is the most commonly used name, it is also known as dillisk or duileasc in Irish Gaelic and söl or søl in Scandinavian languages. Monks living on the Island of Iona of the west coast of Scotland are documented to have eaten dulse 1,400 years ago.

As part of the red seaweed family, dulse is actually distantly related to the wracks and kelps that make up the majority of the biomass in our harvest quotas. The colour is interesting in itself because it is quite variable. Dulse will often be a very dark red, but younger plants usually have a lighter colour. There are more purple tones when submerged, perhaps because of how different wavelengths of light are absorbed under water.

It has a flat frond growing directly from a small holdfast. Individuals in more exposed locations will usually only reach around 20cm, but it can grow to as long as 50cm in perfect conditions. Dulse can be found quite high up the shore, nearly reaching the middle of the intertidal zone. It will tend to be more abundant on the low shore, continuing to be found down to around 20m depths.