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Risso’s dolphin off the Blasket Islands, Co Kerry. Photograph © Simon Berrow/IWDG.
Risso’s Dolphin (Grampus griseus)
Deilf Liath
Risso’s dolphin was the sixth most frequently sighted species
with 252 sightings (3%) totalling 1,983 individuals. They were
consistently the third most frequently reported dolphin
species, after short-beaked common and bottlenose dolphins.
The average group size encountered was five individuals. Most
sightings were between May and July suggesting a late spring
inshore movement, but they were recorded in all areas and in
all months. They were reported off all coasts and were the
dolphin species most regularly recorded in the Irish Sea, with
counties Wicklow and Wexford accounting for 41% of all
inshore Risso’s dolphin sightings. Offshore records were
largely confined to the shelf edge off the southwest coast.
There were 63 recorded strandings since 1926, representing
3.1% of all cetacean strandings. Nearly one-half (48%) of
records have been received since 2000 and there was a
noticeable peak in 2003 with seven recorded strandings.
Three live strandings have been recorded with one in 2002
and two in 2003. The most frequent months for strandings
were May and July, each accounting for 17% compared to the
least in March (3%) and November (2%).
Number of records
6
4
2
0
Records
Live strandings
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Figure 73. Yearly distribution of Risso’s dolphin records 2000-2009.
36
Irish Cetacean Review 2000-2009