Hopes are fading of Fungie returning to Dingle, but new research suggests that “missing” dolphins are more likely to have migrated than died.
Dolphins in the Shannon estuary which were initially presumed to have perished had in fact moved to nearby bays, according to research published by the Irish Whale and Dolphin Group (IWDG).
The study by Kim Ellen Ludwig of Galway-Mayo Institute of Technology (GMIT) found that the “missing” dolphins had “emigrated” to Tralee and Brandon bays in Kerry.
The Shannon estuary’s population of around 140 dolphins provided a good sample for the study. The IWDG – a registered charity founded by Dr Simon Berrow in 1990 – has been monitoring the Shannon bottlenose dolphins since 1993. It constitutes the longest running whale or dolphin study in Ireland.
The group recently explored its 27-year-old identification dataset to see if it could answer the question as to when to consider a dolphin “dead” rather than missing.
Dolphins and whales are highly mobile, ranging thousands of kilometres.
Survival of young dolphins or calves is easier to monitor when dependent on their mothers for survival, and more difficult when they are weaned.
The study with Ms Ludwig indicated that survival rate was 95.6pc for “well marked individual dolphins” – which means around 4.4pc of adult dolphins die each year.
“For less well-marked individuals, survival increases to 5.8pc, due to the higher chance a dolphin is “missed” during surveys,” it sais. The IWDG said that Ms Ludwig’s work highlights “a really important confounding factor, that of emigration outside the Shannon estuary to adjacent Tralee and Brandon bays”.
The dolphins had been presumed dead as these two bays are not routinely sampled. Only by extending their surveys, did the IWDG realise the dolphins were alive and well, and had extended their range.
However in relation to Fungie, estimated to be 37 years old, the IWDG sounds a sombre note. It said that “as the time increases without a sighting and the search effort continues,” it is “more likely” that he is dead rather than missing. It added: “His legacy will live on for years.”
Source: Irish News