Bluefins have only recently reappeared in Irish waters due to improved management; their migration north could impact coastal communities
An Atlantic Bluefin Tuna in the Mediterranean Sea. Photo: iStock
The Atlantic bluefin tuna, one of the most overfished fish species globally, now faces a new threat: warming seas. Marine heatwaves are causing bluefins to migrate to the north, according to a new study by Trinity College Dublin.
Scientists from the Irish Marine Institute, along with Irish anglers, deployed satellite tags on over 50 tuna, according to a statement by Trinity College.
Atlantic bluefins visit the coast of the island of Ireland during the summer and autumn, in the course of their annual migration.
The researchers were able to track the route of the fish for up to 12 months once they left Irish waters with the help of the electronic tags.
“Some fish travelled to the Mid-Atlantic while others travelled to the Mediterranean Sea, possibly to spawn. Several tagged tuna returned to Ireland the following year,” the statement noted.
The monitoring of the fish revealed to the scientists that there are early indications of bluefins moving further north than would be expected. The researchers believe this is due to warming seas.
Bluefins have historically been abundant in Irish waters, like most of the North Atlantic. However, the commercial fishery of the species has been one of the most lucrative globally. This has led to global population crashes and their disappearance from Ireland in the 2000s.
The species has recently made a reappearance in historic feeding grounds around Ireland due to what the College said was improved management over the last decade.
“However, the suitability of these areas for the visiting tuna may be threatened as our climate continues to change,” the statement added.
According to Trinity College, the migration of bluefins northwards could have significant impact on various coastal communities, including some of those in Ireland. This is because Atlantic bluefin are a hugely important species for lots of reasons, it added.
The researchers plans to research other important marine species to gain a fuller picture of how the marine ecosystem surrounding the Irish coast is likely to change in the coming years, so that Ireland can better adapt to those changes.
Seasonal variability of high-latitude foraging grounds for Atlantic bluefin tuna (Thunnus thynnus) was published on June 10 in the Diversity and Distributions journal.
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