Sid Valley Biodiversity Group report: bluefin tuna seen in local waters

PUBLISHED: 12:00 27 September 2020

A bluefin tuna has been spotted in Lyme Bay. Picture: Charles Sinclair/Getty Images

A bluefin tuna has been spotted in Lyme Bay. Picture: Charles Sinclair/Getty Images

Picture: Charles Sinclair/Getty Images

In this week’s report by the Sid Valley Biodiversity Group, publicity officer Charles Sinclair looks at the return of bluefin tuna to local waters.

Would anyone believe me if I said while I was canoeing for mackerel, I saw a tuna jumping in Lyme Bay?

I find it hard to believe myself but it was very distinctive.

It happened twice.

They were 100 metres away and it had me questioning what I saw, but their shape is so familiar.

That was early one evening two weeks ago and since then the local press has reported sightings of tuna in Exmouth, so I don’t feel so daft.

Apparently UK sightings of bluefin tuna have been on the increase since 2012, with one fisherman in Falmouth reporting 45 sightings in 2018.

The University of Exeter is involved in a study of tuna to try and understand their movements and distribution.

The evidence is clearly indicating a return of tuna to UK waters.

They were once quite common here, hence the foundation of the British Tunny Club in 1931.

Then 1940 saw the beginning of the decline in numbers in UK waters and by 1990 they were all but gone.

So why are they back?

Climate change is playing a part but the greatest influence is as a result of the Atlantic Multidecadal Oscillation.

This is a swing in the currents in the Atlantic that bring warmer waters to our shores about every 60 years and we are about 20 years into the warmer cycle.

The tuna are moving up from the Mediterranean and are being found in increasing numbers in the North Atlantic.

They are a globally endangered species; the fact that they are now more common in our waters is not necessarily an indication of their numbers increasing.

What to look out for?

Maybe the best thing to look for if you want to spot tuna is a feeding frenzy.

These are large circular areas of splashing water often with seabirds diving into the sea amongst the foaming waves.

Otherwise, look out to sea for tuna jumping, their bubble-like body and fine tail make them easily recognisable.

The Sid Valley Biodiversity group would be very interested in any of your wildlife sightings, please email sidvalleybiodiversity@yahoo.com


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