Harbour porpoise is the smallest species of whale in Irish waters. They are 1.5 – 1.9 metres in length. They frequent Clew Bay but are averse to boat engine noise and are more likely detected by sailors in sea state 2 or less. Porpoises have been seen in Clew bay regularly from Curraun to Inishgort.
Due to their slow, forward rolling movement, they rarely produce splashes and can be quite difficult to see in choppy seas or large swells. In calm conditions they can be detected by the sound of their short, sharp blows, which are generally not visible. Diving gannets and feeding seabirds often associate with foraging porpoises and may point to their whereabouts.
Porpoises typically surface briefly 3-4 times in a row before diving for up to eight minutes, although when not hunting may surface less frequently. Porpoises eat herring, mackerel, sprat, pollack, hake, sardines, and sand eels. Foraging areas are often associated with strong tidal currents, especially off headlands or between islands.
Of the 24 species of whales and dolphins in Irish waters 16 species have been recorded in Clew Bay including astonishingly Beluga whales in 1948 (O’Riordan 1972).
Between May and September 2005 and 2007 visual and acoustic survey work revealed bottle nose dolphin and harbour porpoise frequenting Clew Bay. 11 Bottle nose dolphins were photo-identified. Static acoustic monitoring using TPODS carried out at Clare island salmon farm at Portlea, east of Clare Island revealed the presence bottlenose dolphins and harbour porpoise (O’Brien J 2009).
If anyone is interested in helping record Harbour porpoises in Clew Bay please text sighting records to me at mob:0834658374