Oyster Thief

Colpomenia peregrina

"Colpomenia peregrina" is a brown seaweed not native to the British Isles, but recorded in Ireland since 1934. It appears to have been introduced from the Pacific and was first noticed in Europe in 1906 on oyster beds.
Oyster Thief - Colpomenia peregrina *I'm wearing gloves because I promised my husband that I would try to stop touching everything -- specifically things that I don't know are safe to touch. ;P I found a lot of these in and around the tide pools during low tide. They felt like big, rotten grapes. Habitat: Tide pools during low tide https://www.jungledragon.com/image/153751/oyster_thief_-_colpomenia_peregrina.html https://www.jungledragon.com/image/153753/oyster_thief_-_colpomenia_peregrina.html https://www.jungledragon.com/image/153752/oyster_thief_-_colpomenia_peregrina.html Colpomenia peregrina,Geotagged,Oyster Thief,Summer,United States

Appearance

"Colpomenia peregrina" Derbès et Solier var. "peregrina" Sauvageau) is a small brown alga, bladder-like, hollow and membranous, up to 9 cm across. The surface is thin and smooth but often collapsed or torn when older. Olive brown in colour and attached by rhizoidal filaments to rock at the base.
There are two species in Europe: "C. sinuosa" Derb. & Sol. and "C. peregrina" Hamel. "C. sinuosa" was present at least as far back as the 1840s in Spain and "C.peregrina" was introduced and first noticed by oyster fishermen in the Bay of Biscay in 1906. It was first noticed in Britain in 1907 in Cornwall and Dorset.
The two species are superficially similar and in older texts, such as Knight and Parke, "C.peregrina" is referred to as "C.sinuosa".

"Leathesia difformis" is similar, it is yellow brown in colour, fleshy and mucilaginous in texture. It is globose and smooth when young becoming hollow and convoluted with age and growing to 5 cm in diameter. It is easily distinguished as it readily squashes when pressed under finger and thumb.
Oyster Thief (Colpomenia peregrina) This is a thin walled brown algae with broad semi spherical thallus (algal body). This free-floating specimen was found in a rock pool having been torn off its "moorings". The algae look like shower caps with puckered edges. These spherical algae are usually epiphytic on other algae or grow on oysters or mussels attaching themselves with filamentous growths. The sphere is inflated with gas and when there is enough gas, the algae floats away with the oyster that it is attached to - hence the name "oyster thief" - an interesting story ! Natural to the Pacific ocean, they spread through Europe in oyster catches and now are found as far south as the southern Australian Coast. Australia,Colpomenia peregrina,Geotagged,Summer

Distribution

;Ireland
"Colpomenia peregrina" has been recorded in Ireland from Counties: Down, Donegal, Kerry, Galway, Clare and Cork. Apparently this alga was first recorded in Ireland by M.J.Lynn from Strangford Lough in March 1934 and from Lough Larne near Ballycarry and Magheramorne in 1935. It was also recorded from Portballintrae, on the north coast, and in the south at Lough Ine. In 1936 it was found at Rush and at Killough. There are further records of from: Portstewart, cast ashore at Hood's Ferry, Islandmagee,. It is now abundant.

;Britain
Generally around the British Isles. In Hardy and Guiry it is shown to be generally recorded around Ireland, south west England, Wales and the west coast of Scotland. Records from the east of Scotland are few and it not shown as present on the east or south east coast of England.
It is noted as a recent addition to the flora.

;Europe
"C. peregrina" was first recorded in Europe in 1908.Mediterranean.

;North America
Alaska to La Jolla, California.
Oyster Thief - Colpomenia peregrina I found a lot of these in and around the tide pools during low tide. They felt like big, rotten grapes. Habitat: Tide pools during low tide https://www.jungledragon.com/image/153751/oyster_thief_-_colpomenia_peregrina.html https://www.jungledragon.com/image/153753/oyster_thief_-_colpomenia_peregrina.html https://www.jungledragon.com/image/153752/oyster_thief_-_colpomenia_peregrina.html Colpomenia,Colpomenia peregrina,Geotagged,Oyster Thief,Summer,United States,bladder weed,brown seaweed

Habitat

Found in littoral rock pools, not exposed and in the sublittoral to 3m depth.

References:

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Taxonomy
KingdomChromista
DivisionOchrophyta
ClassPhaeophyceae
OrderScytosiphonales
FamilyScytosiphonaceae
GenusColpomenia
SpeciesC. peregrina
Photographed in
Australia
United States of America