Sponges, kelp & seals

Seal at Rue Point


Rathlin Island is one of the most important areas in Europe for sponges. In 2007, a team of scientists discovered 28 new species in the seas around the island during a six-week expedition, and three species which had never before been seen in the British Isles. Project director Bernard Picton, curator of marine invertebrates at the Ulster Museum’s department of zoology, said the findings confirmed the significance of the area for these small marine animals.

Sponges feed by filtering particles from the water and play a key role in the marine environment. There are about 15,000 species in the world yet only 400 of these have so far been found in the waters around Britain and Ireland.

Divers from the same team, from the Environment and Heritage Service and Ulster Museum, made another discovery in June 2007. A specimen of the rare Fan Mussel (atrina fragilis), Britain’s largest and rarest bivalve mollusc, thought extinct in Irish waters, was found off Rathlin. The mollusc is extremely vulnerable to pollution, trawling and dredging and this is a significant find, especially if a larger population exists.

Rathlin seabed fly-by

Old Kelp Store at Church Bay


A prominent feature of the waterfront of Rathlin’s Church Bay is the old kelp store (left). Until the 1930s, when artificial methods replaced it, kelp was a rich source of iodine and soda for glass and soap manufacture and the islanders made an income by gathering it. Once dry, the kelp was burned and the sites of 83 kilns have been found on the island – though 150 were recorded in the mid-19th century. Kelp production ended in Rathlin in 1938 – 25 years after the Antrim mainland.

Kelp on Rathlin

Parliamentary Debate, Dublin, 1938

Uses of kelp

Seal at Rue Point


A colony of about 100 seals can be found at Rue Point on the east of Rathlin. They are easy to approach but care should be taken not to disturb them, particularly in the breeding season. A boat trip is the best way to see the colony, as they will investigate the boats in their home environment,




Rathlin has been selected as a Special Area of Conservation:

SAC website

The threat of plastic