Saline and brackish lagoons are among the rarest coastal habitats in Britain. There are only around 360 saline lagoons covering 5,200 hectares in the UK, and they are listed as a priority Natura 2000 community. Formed where the sea is partially cut off from the open coast by shingle banks, sandbars or man-made sea defences, lagoons develop a unique chemistry — part salt, part fresh — that supports highly specialised communities of plants and invertebrates found nowhere else. Some species are endemic to only one or two lagoons in the entire country.

Widewater is one of the finest examples on the south coast. This 8.8-hectare coastal saline lagoon is separated from Lancing Beach by a man-made shingle bank, and is owned by West Sussex County Council and managed by Lancing Parish Council. It was granted Local Nature Reserve status in recognition of its exceptional wildlife interest. Comparable protected lagoons nearby include the Ferry Pool at Pagham Harbour — an SSSI, Special Protection Area and Ramsar site — and the lagoons within Chichester Harbour. What makes Widewater particularly extraordinary, however, is its association with Ivell’s sea anemone (Edwardsia ivelli), a tiny worm-like species endemic to England and known from only one site in the world — Widewater Lagoon itself, where it was first discovered by Professor Richard Ivell in 1973. It has not been recorded since 1983, and is considered possibly extinct by some conservationists, its habitat threatened by reduced seawater inflow and pollution from garden run-off. The installation of the sea inlet pipe visible in the images below was part of efforts to restore the lagoon’s salinity and hydrology.