The Isles of Scilly are a granite archipelago situated approximately 28 miles off the south west coast of Cornwall, renowned for their pristine marine environment. Due to their southerly location, lack of coastal influences and range of exposures, the range of species found here is different from mainland UK. The five main islands - St. Mary’s, St. Martin’s, Tresco, St. Agnes and Bryher - are permanently inhabited, supporting tourism, fishing and small-scale farming. Hundreds of smaller islands and rocks make up the archipelago.

The Isles of Scilly Special Area of Conservation (SAC) was designated in 2005, and encompasses all of the main islands and outlying rocky islets and protects a range of habitats and species: sub-tidal sandbanks, reefs, intertidal mudflats and sandflats, grey seals, shore dock. Key pressures that may be impacting the site are commercial and recreational fishing, commercial and recreational boating, and other watersports, as well as potential nearshore water quality impacts.

Great Little Bay St Martins Isles of Scilly. Credit BareFoot Photographer
Great Little Bay St Martins Isles of Scilly/BareFoot Photographer

Extensive intertidal sandflats are present in the shallow water between the islands, and these sandflats often extend into the subtidal, where they support one of the main surviving seagrass habitats around the UK.

Seagrass meadows around Scilly have been found to contain plants with the longest and thickest leaves (an indication of plant health), but even Scilly’s seagrass is potentially under threat and studies in recent years have shown declines in extent and an increase in the patchiness of some its seagrass beds.

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View from St Martins. Image: Fiona Crouch

Scilly Seagrass Survey 2020

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