Codium fragile
Encyclopedia
Codium fragile, also known as Green sea fingers, Dead man's fingers, felty fingers, felt-alga, Green sponge and Green fleece is an invasive species
of seaweed
in the family Codiaceae
.
This siphonous alga is dark green in colour. 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 branches, or fingers, are up to 1 cm wide, and can extend to lengths of over 30 cm.
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.
around 1808. From there it may have spread by rafting or floating in the sea. Approximately 30 years later, it was found in Scotland
. Codium fragile subsp. atlanticum 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
.
, from the Gulf of St. Lawrence in Canada to North Carolina
. It is a rapidly spreading invasive species.
It originated in the Pacific Ocean
around Japan, and was introduced into New York
from Europe
in 1957. Its presence was first recorded in 1964 in the Gulf of Maine
at Booth Bay
.
This is a dominant subspecies in the subtidal zone, attaching to almost any hard surface. This results in increased maintenance labor for aquaculturists, while reducing the productivity of cultured species of marine life. In established shellfish
beds, this species can become a nuisance; when wave energy lifts the alga, it floats away and carries the host shellfish away with it. This is the source of the common name "oyster thief".
in 1919.
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
of seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
in the family Codiaceae
Codiaceae
In taxonomy, the Codiaceae are a family of algae, specifically of the Bryopsidales....
.
This siphonous alga is dark green in colour. 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 branches, or fingers, are up to 1 cm wide, and can extend to lengths of over 30 cm.
Codium fragile occurs in the low intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...
, and subtidal on high energy beaches.
It has no asexual (sporophyte) stage, and male and female gametes are both produced on separate plants.
Codium fragile subsp. atlanticum
Codium fragile subsp. atlanticum (A. Cotton) Silva, is known to have arrived in the southwest of IrelandIreland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
around 1808. From there it may have spread by rafting or floating in the sea. Approximately 30 years later, it was found in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. Codium fragile subsp. atlanticum is thought to have originally come from the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
near Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
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
Berwick-upon-Tweed
Berwick-upon-Tweed or simply Berwick is a town in the county of Northumberland and is the northernmost town in England, on the east coast at the mouth of the River Tweed. It is situated 2.5 miles south of the Scottish border....
and St. Andrews, Fife
Fife
Fife is a council area and former county of Scotland. It is situated between the Firth of Tay and the Firth of Forth, with inland boundaries to Perth and Kinross and Clackmannanshire...
, a distance of 80 km. Populations of this algae occur mostly in northern Britain. Elsewhere in Europe, it is found only in Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
.
This species displaces the native Codium tomentosum.
Codium fragile subsp. atlanticum is used as food in the Far East
Far East
The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...
.
Codium fragile subsp. tomentosoides
The subspecies Codium fragile subsp. tomentosoides (van Goor) P.C. Silva, (synonym Codium mucronatum var. tomentosoides (van Goor)), commonly known as dead man's fingers, green fleece, green sea fingers, oyster thief, and Sputnik weed, occurs along nearly the whole coastline of the eastern United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, from the Gulf of St. Lawrence in Canada to North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
. It is a rapidly spreading invasive species.
It originated in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
around Japan, and was introduced into New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
from Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
in 1957. Its presence was first recorded in 1964 in the Gulf of Maine
Gulf of Maine
The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America.It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. It includes the entire coastlines of the U.S...
at Booth Bay
Boothbay, Maine
Boothbay is a town in Lincoln County, Maine, United States. The population was 2,960 at the 2000 census. It includes the villages of East Boothbay and Trevett. The Boothbay region is a center of summer tourist activity, and a significant part of its population does not live there year...
.
This is a dominant subspecies in the subtidal zone, attaching to almost any hard surface. This results in increased maintenance labor for aquaculturists, while reducing the productivity of cultured species of marine life. In established shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
beds, this species can become a nuisance; when wave energy lifts the alga, it floats away and carries the host shellfish away with it. This is the source of the common name "oyster thief".
Codium fragile subsp. scandinavicum
This subspecies was introduced from Asiatic coasts of the Pacific to Norway, and to DenmarkDenmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
in 1919.
Further reading
- Hardy, F.G. 1990. The green seaweed Codium fragile on the Berwickshire coast. History of the Berwickshire Naturalists' Club
