Wildlife of Ireland’s Lakes

The great variety of Ireland’s lakes, both in size and in nature, provide a range of habitats that hold a wide spectrum of wildlife species, from the tiniest aquatic insects to the huge flocks of wintering waterfowl. Some of these animal and plant species are well-known and studied, but many are not and there is much scope for the wildlife enthusiast to explore.15282070766_61aa003cc4_z

The most important mammal to be found in Ireland’s lakes is the otter Lutra lutra, a species which has undergone declines over much of its range in Europe and for which Ireland represents a remaining stronghold. However, its elusive nature and mainly nocturnal habits result in fewer sightings than those of the introduced American mink Mustela vison with which it is sometimes confused.

It is the birds of Ireland’s lakes that are the best known, most studied and most observed. Many of the large and medium sized lakes hold good breeding and wintering populations of ducks, swans and other waterfowl such as coots. The Birdwatch Ireland coordinated Irish Wetland Bird Survey (IWeBS) (see www.birdwatchireland.ie) which carries out regular counts of wintering waterfowl provides a wealth of information on the species to be seen on the lakes. In addition, some of the lakes have colonies of breeding gulls and terns, as well as many other aquatic or semi-aquatic species.


The apex predator on Ireland’s waterways has to be the White-Tailed Sea Eagle Haliaeetus albicilla. These spectacular birds of prey  have a wingspan of 2.18 m (7.2 ft), which is the largest of any eagle. White-Tailed Sea Eagles from Norway were reintroduced back into the south-west Ireland after an absence of 110 years. A breeding pair has successfully established themselves on Lough Derg.


The reed beds fringing many of the lakes are also important roosting habitats for several species of birds including swallows, sand martins, starlings and pied wagtails.

At international level, populations of many amphibians are known to be in decline and, although our lakes support only two species, the common frog Rana temporaria and the smooth newt Triturus vulgaris, they are still relatively widespread and abundant.

The fish species are particularly interesting, with salmonids (Atlantic salmon, brown trout and arctic char) being common and the rare pollan Coregonus autumnalis occurring in some lakes. Pike, perch, roach, bream, tench and carp are also widespread.

Dragonflies are abundant, with close to 30 species in Ireland, most of which occur in the lakes. But there are also many other aquatic and semi-aquatic insects of interest, including mayflies, caddis flies, water boatmen, water beetles and even some species of moths that have caterpillars reliant on aquatic vegetation.

The fauna of turloughs, the seasonal ‘disappearing’ lakes of limestone west of the Shannon, is particularly interesting. Many species of aquatic crustaceans have special adaptations to enable them to survive the dry summer period. These lakes are also often important wintering grounds for visiting waterfowl, especially ducks and swans.

For those interested in flora, there is a wealth of aquatic plant species in the lakes, notable among which are the charophytes (stoneworts) found in many of the limestone lakes in the west and midlands.