The strong currents around the island provide for an abundance of marine life, particularly on the north coast, where the depths reach . Many people enjoy fishing trips departing from Beaumaris in these waters, catching mainly mackerel, but many other species are caught. The abundance of fish feeds a large colony of grey seals, and bottlenose dolphins and harbour porpoises regularly visit the area. Pleasure cruises are also available from Easter to October to view the island, its seal colony and birdlife.