Download . Japanese kelp, Undaria pinnatifida Overview Overview table

Japanese kelp, U n d a r i a p i n n a t i f i d a
Overview
.
Short description of U n d a r i a p i n n a t i f i d a, 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 U n d a r i a p i n n a t i f i d a, Japanese kelp status in GB
Author's name:
Wakame has been recorded from the Hamble (Solent), Isle of Wight, Torquay,
Plymouth and Jersey.
Jack Sewell
H a b i t a t s u m m a r y : U n d a r i a p i n n a t i f i d a, Japanese kelp
Last updated:
January 6th, 2012
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.
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Overview table
Environment:
Marine
Species status:
Non-Native
Native range:
China, Kazan-retto, Nansei-shoto, Ogasawara-shoto,
North Korea
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:
2015
Invasion history: U n d a r i a p i n n a t i f i d a, Japanese kelp
Origin
Native to cold temperate areas of Japan, China and Korea
First Record
The first GB record of Wakame is from the River Hamble Estuary, in the Solent in 1994.
Pathway and Method
Introduced to GB via secondary introductions from France, where it was introduced
unintentionally with Pacific oysters and intentionally to be grown as a commercial food
crop. It is thought to have been accidentally introduced to GB from continental Europe
attached to ships’ hulls.
Species Status
Wakame has been accidentally introduced to Australia, New Zealand, Tasmania, and
the Mediterranean Sea (France, Italy). It was deliberately introduced to Brittany for
commercial exploitation. Following introduction, wild communities have been recorded
in France, GB, Spain and Argentina. After being recorded from the Hamble in 1994 its
range had extended between Ramsgate and Torquay, in 2004 and Wakame Is now also
found on the shores and marinas around Plymouth and elsewhere on the South Coast
of England.
Ecology & Habitat: U n d a r i a p i n n a t i f i d a, Japanese
kelp
Dispersal Mechanisms
Wakame has two distinct life stages. A large macroscopic (sporophyte) stage
produces microscopic spores, which may be dispersed by water currents although
sporophytes must settle in sufficient densities for fertilization to take place.
Sporophytes may themselves attach to loose objects, allowing them to be naturally
dispersed by currents.
Reproduction
In its native habitat, sporophytes grow rapidly in winter and spring when sea surface
temperatures are 5-13°C. Growth is optimal at 10°C. The zoospores are released in
late spring or early summer, when temperatures are between 7 and 20°C. The
zoospores germinate at 20°C, and are sexually mature in about 3 weeks. At higher
temperatures, the longevity and chances of germination of the sporophyte decline.
Wakame’s two-stage life history, requires high densities of spores to settle together
before fertilisation can occur. Release of spores can continue even when the stipes
are devoid of their blade.
Known Predators/Herbivores
Possible predators in GB could include blue-rayed limpets (Helicon pellucidum), sea
hares (Aplysia spp) and species of sea urchin.
Resistant Stages
The zoospore stage is microscopic, making detection difficult. This stage and can
survive in a range of temperatures.
Habitat Occupied in GB
Found subtidally and in the very low intertidal can rapidly colonize new or recently
disturbed man-made structures such as floating marina pontoons, rope, pylons, vessel
hulls and navigation buoys. It can grow at depths of up to 18 m and can grow in a
wide range of wave exposures, from sheltered marinas to the open coast. May also
grow on loose cobbles and shells.
Distribution: U n d a r i a p i n n a t i f i d a, Japanese kelp
Native to cold temperate areas of Japan, China and Korea, it has been accidentally
introduced to Australia, New Zealand, Tasmania, and the Mediterranean Sea (France,
Italy). It was deliberately introduced into the North Atlantic, to Brittany for commercial
exploitation. Following introduction, wild communities have been recorded in France,
GB, Spain and Argentina. On the British coast its range had extended between
Ramsgate and Torquay, in 2004. Wakame Is now also found on the shores and marinas
around Plymouth and elsewhere on the South Coast of England.
I m p a c t s : U n d a r i a p i n n a t i f i d a, Japanese kelp
Environmental Impact
Wakame is likely to compete for space and resources with native species of kelp and
other brown seaweeds. It may also compete with other epibenthic animals and
seaweeds.
Health and Social Impact
None known.
Economic Impact
Fisheries and mariculture: Industry may be adversely affected by increased costs
associated with handling and marketing fouled shellfish. Commercially important
species may also be adversely affected by indirect ecosystem impacts.
References & Links: U n d a r i a p i n n a t i f i d a, Japanese
kelp
Identification
MarLIN Alien Fact Sheet
MarLIN Species Fact Sheet
Biology, ecology, spread, vectors
Arenas, F., Bishop, J.D.D., Carlton, J.T., Dyrynda, P.J., Farnham, W.F., Gonzalez, D.J.,
Jacobs, M.W., Lambert, C., Lambert, G., Nielsen, S.E., Pederson, J.A., Porter, J.S., Ward,
S. & Wood, C.A. (2006) Alien species and other notable records from a rapid
assessment survey of marinas on the south coast of England. Journal of the Marine
Biological Association of the United Kingdom, 8 6, 1329-1337.
Castric-Fey, A., Girard, A. & L'Hardy-Halos, M.T. (1993) The distribution of Undaria
pinnatifida (Phaeophyceae, Laminariales) on the coast of St. Malo (Brittany, France).
Botanica Marina, 3 6, 351-358.
Castric-Fey, A., Beaupoil, C., Bouchain, J., Pradier, E. & L’Hardy-Halos, M.T. (1999) The
introduced alga Undaria pinnatifida (Laminariales, Alariaceae) in the rocky shore
ecosystem of the St Malo area: growth rate and longevity of the sporophyte. Botanica
Marina, 4 2, 83-96.
Sliwa, C., Johnson, C.R., Hewitt, C.L. (2006) Mesoscale dispersal of the introduced kelp
Undaria pinnatifida attached to unstable substrata. Botanica Marina, 4 9, 396–405.
Farell, P. & Fletcher, R. (2000) The biology and distribution of the kelp, Undaria
pinnatifida (Harvey) Suringar, in the Solent. Amsterdam: Elsevier Science B.V.
http://www.marlin.ac.uk/marine_aliens/species.asp?SpID=22
http://www.marlin.ac.uk/speciesinformation.php?speciesID=4547
Management and impact
Wotton, D.M., O’Brien, C., Stuart, M.D. & Fergus, D.J. (2004) Eradication success down
under: heat treatment of a sunken trawler to kill the invasive seaweed Undaria
pinnatifida. Marine Pollution Bulletin, 4 9, 844-849.
General
MarLIN Alien Fact Sheet
MarLIN Species Fact Sheet