Lake Bursts & a Mermaid Becomes a Saint

A lake-burst, in Irish, tomhaidhm is a phenomenon referred to in Irish mythology, in which a previously non-existent lake comes into being, often when a grave is being dug. Part of the lake-burst stories may originate in sudden hydrographic changes around limestone-based inland plains or turloughs.

in the legend surrounding the lake burst of Lough Neagh, a woman turned mermaid. Her family was drowned, but she survived in an underwater chamber in the lake for a year, after which she was transformed into a being who was half-human, half-salmon.

In her mermaid form, she was spotted a monk carrying a messenger sent by St Comgall to Rome. She promised to meet at the seaport inlet of Inbhear nOllarbha in Ireland after one year, and was captured in a fishnet. There she was baptised by Comgall, and given the Christened name Muirgein ("sea-born"). She appears canonized as St. Muirgen in genealogies of Irish Saints and her feast day assigned to 27 January.