BIOTIC

BIOTIC Species Information for Himanthalia elongata
All Taxonomy Biology Distribution Reproduction

Researched by	Nicola White	Data supplied by	MarLIN
Refereed by	Dr Dagmar Stengel
Distribution and Habitat
Distribution in Britain & Ireland	All coasts of Britain and Ireland, except south east England.
Global distribution	Norway, Britain, Ireland, north west coast of France, northern Spain and Portugal.
Biogeographic range	Not researched	Depth range	Not relevant
Migratory
Distribution Additional Information	The distribution of Himanthalia elongata appears to be controlled by the degree of wave exposure, presence of tidal currents and the availability of suitable substrata. The species grows best in areas with strong tidal currents and is most commonly found on semi-exposed shores where, it can be locally abundant. It is rarely found in exposed shores and occasionally forms dense stands on sheltered shores. The degree of exposure to waves is also important in determining the persistence of adult plants on the shore. On exposed sites, adult plants may only be present until October, whereas on sheltered sites, plants may be present until February. Zygotes of this species are intolerant of lowered salinity and silt, restricting the species' distribution. Himanthalia elongata is typically found in the lower eulittoral and sometimes extends into the shallow sublittoral. The species can tolerate the physical conditions found further up the shore, but it is prevented from growing there by grazing pressure. Plants from exposed sites tend to be shorter and have fewer, narrower receptacles. Plants grow well in the presence of a red algal turf, which offers protection to young vegetative stages from wave action.

Substratum preferences	Bedrock Large to very large boulders	Physiographic preferences	Open coast Strait / sound Sealoch Ria / Voe
Biological zone	Lower Eulittoral Sublittoral Fringe	Wave exposure	Moderately Exposed Sheltered
Tidal stream strength/Water flow	Strong (3-6 kn) Moderately Strong (1-3 kn) Weak (<1 kn)	Salinity	Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References	Stengel et al., 1999, Moss et al., 1973, Hardy & Guiry, 2003,