Survey of coastal lagoons within Hampshire and Isle of Wight

The Solent, on the south coast of England, encompasses a series of coastal lagoons, including percolation, isolated and sluiced lagoons. The site includes a number of lagoons in the marshes in the Keyhaven - Pennington area, at Farlington Marshes in Chichester Harbour, behind the sea-wall at Bembridge Harbour and at Gilkicker, near Gosport. The lagoons show a range of salinities and substrates, ranging from soft mud to muddy sand with a high proportion of shingle, which support a diverse fauna including large populations of three notable species: the nationally rare foxtail stonewort Lamprothamnium papulosum, the nationally scarce lagoon sand shrimp Gammarus insensibilis, and the nationally scarce starlet sea anemone Nematostella vectensis.

The lagoons in Keyhaven - Pennington Marshes are part of a network of ditches and ponds within the saltmarsh behind a sea-wall. Farlington Marshes is an isolated lagoon in marsh pasture that, although separated from the sea by a sea-wall, receives sea water during spring tides. The lagoon holds a well-developed low-medium salinity insect-dominated fauna. Gilkicker Lagoon is a sluiced lagoon with marked seasonal salinity fluctuation and supports a high species diversity. The lagoons at Bembridge Harbour have formed in a depression behind the sea-wall and sea water enters by percolation. Species diversity in these lagoons is high and the fauna includes very high densities of N. vectensis.

Natural England wishes to commission a repeat condition monitoring survey, following the surveys conducted in 2013 by Bamber et al. (2013), of twenty coastal lagoons within the Solent and Isle of Wight region, to be conducted during summer/autumn 2020. Survey data will inform the update to the condition assessment for the Solent & Isle of Wight Lagoons SAC and Solent Maritime SAC planned for Spring 2021.