As part of a scheme to monitor the distribution of otters throughout the UK, two otter surveys in Northern Ireland have been carried out covering the years 1980-81 (funded by The Vincent Wildlife Trust as part of an all Ireland survey) and 2001-02 (Environment and Heritage Service (EHS), NI). The 1980-81 survey covered 10km areas within alternate 50km squares of the Irish National Grid using sites that were accessible and where there would be a likelihood of finding signs of otter activity—typically road bridges and the confluences of watercourses. In the second survey (2001-02) 131 positive and 50 negative sites of the 1980 survey were re-sampled plus 441 new sites and combined with an intensive survey of Lough Erne (a designated cSAC for otters).
There are also Otter Survey databases for Scotland, England and Wales.
