Marine and coastal policy

EU Life-Nature Saline Lagoons Project

Background to saline lagoons

Little tern on nest
A large proportion of England's little terns depend on saline lagoons

Saline lagoons are rare and localised in Britain and Europe - because of this, they are a priority habitat in the EU Habitats Directive.

There are only about 1,300 hectares of saline lagoons in England, and most of these are threatened by loss and degradation.

Saline lagoons are extremely important for wildlife; the avocet breeds on almost no other habitat in north west Europe; a range of terns and gulls also breed including a large proportion of Englands little terns and Mediterranean gulls; they are used by tens of thousands of waders and ducks for feeding and roosting on migration and in winter.

Saline lagoons are extremely important for wildlife; the avocet breeds on almost no other habitat in north west Europe

However, much of the importance of saline lagoons lies beneath the surface; there are species of invertebrate and plant that can live in no other habitat, and 13 of these are so rare and threatened that they are listed in the UK Red Data Book.

What are saline lagoons? They are areas of open water on the coast that are influenced by the sea and by freshwater from the land. They are usually shallow and although connected to the sea to receive salt water, do not suffer the full range of the tide. It is these relatively stable conditions at or often a little less than the salinity of the sea, which are the conditions that specialist wildlife needs.

Avocets feed on small invertebrates in the soft mud at the bottom of the lagoons (the benthos). They can breed at higher densities and more successfully when the density of invertebrates (the biomass) is high.