The species is protected under Jersey law, with anyone found to have killed one liable for up to two years' in prison, and could be fined.

The project to tag the Bluefin tuna, which began in 2021 with a collaboration between Marine Resources and the University of Exeter, aims to help keep a closer eye on the protected species. The Bluefin Tuna are tagged using state of the art satellite tags which will be on the fish for one or two years until it automatically detaches. 

Pictured: a Bluefin tuna displaying a satellite tag. 

This year, a further seven bluefish tuna have been tagged on top of the seven tagged in 2021. Four of the seven tags deployed in 2021 have now been collected by Marine Resources and analysed by the University of Exeter.

The data from these tags shows, amongst other things, that the fish are arriving from further south, some from the Bay of Biscay and some as far as the Mediterranean spawning grounds. Not all fish are spawning – some are juveniles whereas others are sexually mature and are returning to known spawning grounds in the winter. Two bluefin tuna tagged in 2021 returned to Channel Island waters in 2022 with the tags being retrieved by Marine Resources and local commercial fishers.

Watch: A Bluefin tuna being tagged by researchers. 

A number of the fish tagged last year were caught before the tags detached, demonstrating the vulnerability of this species. 

Alex Plaster, Marine Science and Research Officer, said: “It’s great to work collaboratively with the team from the University of Exeter and Fishing Jersey for a second year running. Two of the tags we deployed last year popped off within reach for us to go and collect them - one was 70 miles west of Jersey and the other just west of Les Minquiers. These fish are travelling incredible distances and with this satellite data we can calculate the migration route of the animal.

Pictured: Alex Plaster, Marine Science and Research Officer, in the process of tagging a Bluefin tuna. 

"The Norman le Brocq collected one of these using tracking equipment and we also had two volunteers from the Jersey fishing fleet who collected the other tag. The data we receive from the satellite tags tells us crucial information to manage this resource such as how long they are in our waters for and what they are doing here.

"We have found out some of these fish are travelling as far as Turkey and three of the fish tagged in 2021 were caught within 12 months in the English Channel, Bay of Biscay and Mediterranean. Marine Resources will be publishing a report on the findings next year.”