Bottlenose Bonanza for N. Ireland - a sign of change?

3rd Jun 2008 The past few days has seen an exceptional run of Bottlenose Dolphin Tursiops truncatus records in counties Derry, Antrim and Down. The first sighting of a group of c12 was in Portrush , Co. Antrim on Friday 30th May with possibly the same group spotted by surfers at Portstewart and later at Portballintrae. Finally on Saturday a smaller group of c7 was seen off the Outer Ards coast in Co. Down, off Burial Island.

Bottlenose Dolphin was thought of as being comparitively rare around the Northern Ireland coast and indeed right down the east Irish coast. From Donegal west and south to Kerry, the Atlantic coast has been the stronghold for this robust and often acrobatic dolphin. But are things changing?

Before 2005 a total of 15 sighthings were recorded from coastal sites between Derry, east and south to Wicklow. Since 2005 this figure is now 51 (with some of the recent sightings still to be validated and listed) - more than a three-fold increase. It is notable that Bottlenose Dolphin hotspots e.g. in Cork, Kerry and Clare for the same periods show a more even sightings distribution over time. This may simply be a reflection of greater recent observer effort and public interest away from the traditional cetacean watching areas in the west and south-west. However the Dublin area has a good history of recording (631 records in the database) of which, prior to 2005 only 1 record referred to Bottlenose Dolphin - since then 16 records have been accepted.

Coastal populations of this species are thought to be affected by sea warming events off California - this associated with El NiƱo events. There the dolphins are pushed further north by sea temperature rises presumably reflecting a redistribution of prey. With evidence of temperature increases in the Irish Sea over the past 20 years especially, perhaps conditions are now more suitable for this magnificent dolphin in the Irish Sea basin. An east coast gain from climate change?

Thanks as always to Helen White (IWDG) and Richard Weyl (EHS) for reporting this latest activity to us.

Ian Enlander

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