Warming seas linked to Bluefin tuna surge in UK waters

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Bluefin tuna is said to be one of the biggest and quickest fish on Earth – they measure about 900 kilograms and can travel up to 70 kilometers per hour.

In the 1930s, this species was familiar in the depths of Scarborough and also was given a high price by lots of big-game fishers, but in the 1940s, their numbers started to drop, and at the beginning of the 1990s, they had all but vanished. However, for the last 5 years, the findings on this species have heightened in the UK once more, and these are posted on social media.

Experts now consider that the Atlantic Multidecadal Oscillation (AMO)’s cooling and warming effect of the long-term current is the solution to the decline and growth of these species. AMO is the common climate cycle in the Northern Atlantic that oversees grow and decline of temperatures in a long period of time.

The scientists’ research entitled Atlantic Multidecadal Oscillations drive the basin-scale distribution of Atlantic bluefin tuna is about the shifting abundance and circulation of these species for the last 200 years in the Atlantic. These showed that the primary factor of the movement is the AMO.

“The ecological effects of the AMO have long been overlooked and our results represent a breakthrough in understanding the history of bluefin tuna in the North Atlantic,” said lead author Dr. Robin Falllettaz from the University of Lille.

He considers that if the species sightings have increased for the UK, it does not mean that this would be the case everywhere.

“When water temperature increases during a positive AMO, bluefin tuna move further north. However, the most positive (warming) phases of the AMO also have a detrimental effect upon recruitment in the Mediterranean, which is currently the most important spawning ground, and that will affect adult abundance a few years later.”

“If the AMO stays in a highly positive phase for several years, we may encounter more bluefin tuna in our waters but the overall population could actually be decreasing.”

As of the moment, catching Bluefin tuna is banned in the UK. However, the latest growth of this species has encouraged campaigners to start a petition that the government should permit amateur fishers to fish for this endangered species.

“Bluefin tuna have been extensively overfished during the 20th century and the stock was close to its lowest in 1990, a fact that further indicates the recent changes in distribution are most likely environmentally driven rather than due to fisheries management and stock recovery,” said co-author Dr. Richard Kirby from the Secchi Disk Foundation.

“Before we further exploit bluefin tuna either commercially or recreationally for sports fishing, we should consider whether it would be better to protect them by making the UK’s seas a safe space for one of the ocean’s most endangered top fish.”