Mysis salemaai in Ireland: New occurrences and existing population declines

We report three new occurrences of Mysis salemaai, a conservationally important glacial relict at the southern limit of its range, in Castlewellan Lake, Lough Scolban and Lough Macnean Upper, in the north of Ireland. This increases the number of lakes in Ireland where the species has been recorded to fourteen.We consider lake area and maximum lake depth as factors that might determine the long-term survival of M. salemaai populations and show that these populations tend to occur in relatively large, deep lakes. We also show that population densities in Lough Neagh and Lough Erne are declining.