Sea Guernsey - Seaweeds & Eelgrass

Various kelp species, thong weed, and other seaweeds, in a gully on the south coast of Guernsey.

The abundant kelp forests which thrive on the lower shore reefs of the rocky coastlines all around the islands of the Bailiwick of Guernsey support a vast variety of marine life. These teeming forests are essential nurseries, feeding grounds, and shelter, for hundreds of different species from tiny colourful sponges and nudibranchs to commercially important crab and fish species.

Various small brown, red, and green seaweeds, amongst a forest of Wireweed (Sargassum muticum), in shallow sunlit waters on Guernsey's west coast.

These habitats of mixed short seaweeds on stone and sand are home to a multitude of macro life, including hundreds of small blennies, shrimps, gardens of anemones and juvenile wrasse. The Wireweed is a non native invasive species that has now been present in Guernsey for over 30 years and, anecdotally, seems to have reached a balance. Whilst relatively new to our shores, it does create visually stunning forests and can provide cover for a variety of fish species.

A meadow of the eelgrass (Zostera marina) in clear shallow sandy waters on the west coast of Guernsey.

Unlike seaweeds, seagrasses are actually flowering vascular plants, similar to terrestrial grasses, which have adapted marine conditions. Seagrasses provide important ecosystem services including creating habitats for numerous marine species, both above and below the seabed, and their root system binds the sand preventing erosion and, importantly, locking away carbon.