Multiple datasets spanning a 16-year period have shown an increase in bluefin tuna, which arrive into the waters of the Celtic Seas and off SW England, the Scilly Isles, and NW Ireland to feed in late summer and autumn according to research led by Cefas and the University of Exeter, published in ICES Journal of Marine Science (open access).

The study is part of the Defra-funded “Thunnus UK” research project, established to improve knowledge of this species, as an essential first step in ensuring a positive future for Atlantic bluefin tuna around the UK.

Central to the project’s success has been a concerted effort to share and combine important data on where people have observed Atlantic bluefin tuna. Nearly 1000 unique observations were recorded between 2013 and 2018 by citizen scientists, scientists, fishers and eco-tour leaders, with three eco-tourism vessels collecting data on more than 1600 boat tours off the SW coast of England between 2008 and 2018.  Researchers found that Atlantic bluefin tuna begin to arrive in May and stay as late as January. However, peak numbers were recorded between August and October each year.