Codium fragile

Codium fragile
Codium fragile on the Massachusetts coast
Scientific classification
Kingdom:	Plantae
Division:	Chlorophyta
Class:	Bryopsidophyceae
Order:	Bryopsidales
Family:	Codiaceae
Genus:	Codium
Species:	C. fragile
Binomial name
Codium fragile (Suringar) Hariot

Codium fragile, known commonly as green sea fingers, dead man's fingers, felty fingers,forked felt-alga, stag seaweed,sponge seaweed,green sponge,green fleece, and oyster thief, is a species of seaweed in the family Codiaceae. It originates in the Pacific Ocean near Japan and has become an invasive species on the coasts of the Northern Atlantic Ocean.

This siphonous green alga is dark green in color. It appears as a fuzzy patch of tubular fingers. These formations hang down from rocks during low tide, hence the nickname "dead man's fingers". The "fingers" are branches up to a centimeter wide and sometimes over 30 centimeters long.

Codium fragile occurs in the low intertidal zone, and subtidal on high-energy beaches.

It has no asexual (sporophyte) stage, and male and female gametes are both produced on separate plants.

Subspecies of C. fragile can only be distinguished microscopically.

Codium fragile subsp. atlanticum is known to have arrived in the southwest of Ireland around 1808. From there it may have spread by rafting or floating in the sea. Approximately 30 years later, it was found in Scotland. It is thought to have originally come from the Pacific Ocean near Japan.

Since 1840, when it was first discovered in Scotland, it has spread the entire length of Britain, including Shetland. Between 1949 and 1955 it is known to have spread between Berwick-upon-Tweed and St. Andrews, Fife, a distance of 80 km. Populations of this algae occur mostly in northern Britain. Elsewhere in Europe, it is found only in Norway.

This species displaces the native Codium tomentosum.

Codium fragile subsp. atlanticum is used as food in the Far East.

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Wikipedia