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Hopes for Fungie to return to Dingle are fading, but new research suggests that “lost” dolphins are more likely to have migrated than to have 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).
Kim Ellen Ludwig’s study from the Galway-Mayo Institute of Technology (GMIT) found that the “missing” dolphins had “migrated” to Kerry’s Tralee and Brandon Bays.
The Shannon Estuary 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 Shannon’s bottlenose dolphins since 1993. It is the longest running whale or dolphin study in Ireland.
The group recently explored its 27-year-old identification data set to see if it could answer the question of when to consider a dolphin “dead” rather than missing.
Dolphins and whales are very mobile, stretching thousands of miles.
Survival of young dolphins or calves is easier to monitor when they depend on their mothers for survival, and more difficult when they are weaned.
The study with Ms Ludwig indicated that the survival rate was 95.6 percent for “well-tagged individual dolphins”, which means that about 4.4 percent of adult dolphins die each year.
“For the less tagged individuals, survival increases to 5.8 percent, due to the greater likelihood that a dolphin will be lost during censuses,” he says. The IWDG said that Ms Ludwig’s work highlights “a really important confounder, that of migration out of the Shannon Estuary to the adjacent bays of Tralee and Brandon.”
The dolphins are presumed dead as these two bays are not routinely sampled. Only by expanding its studies did the IWDG realize that the dolphins were alive and well, and had expanded their range.
However, relative to Fungie, estimated at 37 years, the IWDG strikes a grim note. He said that “as the time without a sighting increases and the search effort continues,” it is “more likely” that he is dead rather than missing. He added: “His legacy will live on for years.”
Irish independent
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