At least 28 species of cetacean have been recorded in the NE Atlantic from strandings and sighting surveys, with 24 species recorded in the Irish Economic Exclusion Zone. A further 52 species of seabirds have been recorded in Irish waters. Despite the importance of our waters for marine mammals and seabirds, only a small number of dedicated cetacean and seabird surveys have taken place over this wide geographic area.

Under the OBSERVE Programme, a series of four combined line-transect and strip-transect aerial surveys for cetaceans and seabirds in Irish offshore waters will be conducted. The core purpose of these surveys is to estimate and describe animal density, abundance and distribution within the Irish offshore region.

Deriving abundance estimates is an important element in cetacean and seabird conservation management.  Although there are a number of techniques available to estimate abundance, dedicated ship-based and aerial line transect surveys are the most commonly used approach to generate estimates across a wide range of species and over a wide geographical area.  This approach has been used successfully in the Pacific and Atlantic.


The figure shows the extent of the aerial survey transects for marine mammals and seabirds. Surveys were conducted four times, twice in Summer, and twice in Winter, covering over 37,200 kilometers of survey track.

The choice of the most suitable aircraft is vital to the success of the survey. The plane needs to have twin engines for safety, be high-winged to allow an unobstructed view of the area below the plane, be equipped with bubble windows for view of the trackline, be able to travel at low speeds of 80 to 100 knots and have an endurance that allows the safe completion of offshore surveys. We are using the Britten Norman BN2 Islander which meets all the needs of offshore surveys.

The BN2 is equipped with bubble windows that enable unobstructed views of the full track line.