Eelgrass (Zostera marina) beds



GB distribution

Compiled by: Keith Hiscock, English Nature, Northminster House, Peterborough PE1 1UA. UK.

Derived, in part, from: the UK marine biotope classification (Connor et al. 1997b) and a review undertaken for the UK Marine SACs Project (Davison 1998).


Classification Code Biotope(s)
Europe (EUNIS Nov. 1999) A4.5/B-IMS.Sgr.Zmar Zostera beds in lower shore or infralittoral clean or muddy sand.
Wadden Sea 03.02.05 Benthic zone of the shallow coastal waters with muddy and sandy bottom, rich in macrophytes
Britain/Ireland (MNCR BioMar 97.06) IMS.Zmar Zostera marina/angustifolia beds in lower shore or infralittoral clean or muddy sand
France (ZNIEFF-MER) II.3.3


Herbiers de Zostera marina, Zostera noltii (= Z. nana pro parte) du médiolittoral inférieur

Herbiers de Zostera marina


IMS.Zmar. Expanses of clean or muddy fine sand in shallow water and on the lower shore (typically to about 5 m depth) can have dense stands of Zostera marina/angustifolia [Note: the taxonomic status of Z. angustifolia is currently under consideration but is most likely a dwarf form of Zostera marina]. In IMS.Zmar the community composition may be dominated by these Zostera species and therefore characterised by the associated biota. Other biota present can be closely related to that of areas of sediment not containing Zostera marina, for example, Laminaria saccharina, Chorda filum and infaunal species such as Ensis spp. and Echinocardium cordatum (e.g. Bamber 1993) and other bivalves listed below. It should be noted that sparse beds of Zostera marina might be more readily characterised by their infaunal community. Beds of this biotope in south-west Britain may contain conspicuous and distinctive assemblages of Lusitanian fauna such as Laomedea angulata, Hippocampus spp. and Stauromedusae. Some examples of Zostera marina beds have markedly anoxic sediments associated with them.

GB distribution (from MNCR database March 1999)













Habitat requirements

Species composition and biodiversity

Ecological relationships

Sensitivity to human activities

Conservation and protection status