There are few historical references to sea pollution, but the Skibbereen and West Carbery Eagle reported ‘an extraordinary appearance in the sea’ on 6 May 1865 in which a streak of coloured matter appeared in the sea along the West Cork coast. It was reported in Castletownsend, Lough Hyne, Baltimore, Cape Clear and Crookhaven. The reporter described the strange phenomenon thus:
Rowing along we saw that all the ocean waters were not so tinged but that the colour was confined to a streak or river, as it were, in the sea, and along the rocks where no tide swept for about 20 to 30 feet the water was clear as ever.
The water has been described as ‘muddy and forbidding’ as well as being described as looking like ‘the blood of American patriots’. Others thought it may be the ‘mud, scoria and ashes’ from a volcanic eruption. These descriptions suggest it was a reddy-brown colour, which means this could be an example of algal blooms that cause red tides.