Fin whales with Risso’s dolphins off West Cork

How do you trump a week like the one we’ve just had with a humpback whale being tracked between Rathlin Island and Howth Head? Well heading out with Colin Barnes on the MV Holly Jo when fin whales are inshore in West Cork is always a good bet.

On Fri. 23rd July we observed a most unusual sighting on one such trip, as favourable conditions and a run of fin whale sightings suggested Friday would be a good opportunity to attempt some final Photo ID fieldwork. This work was supported by West Cork Development Partnership during the 2009/10 field season.

After two hours searching the waters 12-14 miles SW of Galley Head, a distant surface disturbance lead us to a group of three fin whales….the first I’ve personally seen since Feb 2010 when they were off the Waterford coast, prior to leaving Irish waters. Their behaviour suggested fast travel.

As is common with such fin whale encounters, they were travelling with dolphins, whose splashes ahead of the fin whales, gave away the whales’s presence. But these were clearly not the common dolphins we frequently observe associating with fin whales, but Risso’s dolphins. And having discussed this with Colin and colleagues within IWDG, this is to the best of our knowledge the first time an association between fin whales and Risso’s dolphin has been documented in Irish waters.

Alas due to the high speeds that the fin whales were travelling at, which we estimated at c16 knots+ it was not possible to capture either images of the association or photo ID images of the fin whales. But it is great to see fin whales returning to their West Cork haunts. On the Previous day Thurs. 22/07/10 Colin obseved the fin whale known as “Scar” FWIRL2 in the same area. This easily recognised individual has been seen most years in West Cork since it was first recorded in 2005.

Also observed during the trip were grey seals, harbour porpoises and blue shark (on surface), bringing our sightings tally to an impressive five species in just over 4 hours. 2010 is indeed looking like it’s going to be another fascinating year for large whale studies and observations in Irish inshore waters.

Pádraig Whooley

IWDG Sightings Co-ordinator