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Japanese kelp, Undaria pinnatifida


Short description of Undaria pinnatifida, Japanese kelp

A large brown seaweed, the stipe has very wavy edges or ‘ruffles’ at the base, giving it a corrugated appearance. The blade is broad and flattened with a distinct midrib. The margins of the blade are wavy and ribbon-like at the base. Individuals can reach an overall length of one to three metres. Wakame is an annual species with two separate life stages.

Description of Undaria pinnatifida, Japanese kelp status in GB

Wakame has been recorded from the Hamble (Solent), Isle of Wight, Torquay, Plymouth and Jersey.

Habitat summary: Undaria pinnatifida, Japanese kelp

May be found on hard surfaces, including man-made structures from the low tide mark down as far as 15 metres in clear water. May also attach to bottom dwelling creatures, empty shells, loose cobbles and other seaweed species.

Overview table

Environment: Marine
Species status: Non-Native
Native range: Northwestern Pacific
Functional type: Algae (macroalgae)
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: Hamble estuary
Date of first record: 1994

Distribution map

Map of the UK with areas shaded to show the UK distribution of Japanese kelp

GB Distribution from NBN Atlas

Author's name:

Jack Sewell

Last updated:

October 3rd 2019

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