Saline Lagoons

Lagoons are natural or artificial bodies of saline water partially separated from the sea by shingle, sand, a rocky shore or sea wall. Seawater input can be through percolation, via a channel or by overtopping.

Saline Lagoon

Photo: Peter Wakely/Natural England

Why are they important?

  • The salinity of lagoons can vary considerably, and they support specialised species of plants and animals, which reflect the degree of salinity.
  • Lagoons often have soft sediments (mud or sand) making them important for burrowing invertebrates, and stoneworts some of which are extremely rare.
  • Lagoons provide important habitat for birds.

Saline Lagoons in Sussex

In Sussex saline lagoons cover about 190 hectares over around 30 sites, which is around 3% of the total UK resource.

What are the threats?

  • Saline lagoons will often naturally fill-in through vegetation succession. This would naturally be offset by lagoon creation; however this may be limited by human activity.
  • Pollution, particularly through nutrient enrichment, affects the vegetation community.
  • Artificial control of water input to lagoons will affect salinity.
  • Coastal defence work can interrupt natural sediment movement which affects coastal habitats and structures including lagoons.
  • Sea level rise will lead to the loss of some lagoons; however it may also result in the creation of new ones.

Some associated species

  • Three-spined Stickleback Gasterosteus aculeatus
  • Knot Calidris canutus
  • Sea Slater Ligia oceanica
  • Lagoon Cockle Cerastoderma glaucum
  • Tasselweed Ruppia spp.
  • Foxtail Stonewort Lamprothamnium papulosum


Photo: Ian Rose

Advice on saline lagoons

After Minerals

Sussex Targets

Biodiversity Action Reporting System Website

Download the Saline Lagoons Habitat Action Plan