Atlantic Bluefin tuna is a highly migratory species managed at an international level by the International Commission for the Conservation of Atlantic Tunas (ICCAT), the Regional Fisheries Management Organisation competent for managing Atlantic Bluefin tuna. Separate Bluefin stocks are understood to exist across different areas of the Atlantic. For several years Eastern Bluefin tuna appeared more or less absent from UK waters.
Sightings by scientists conducting surveys, and by members of the public on fishing vessels and leisure boats suggest potentially increased incidence of Eastern Atlantic Bluefin tuna in UK waters in recent years. The reasons for this are not clear, but could include a shift in distribution due to changes in environmental and prey conditions and/or increasing stock size associated with the stock's recovery. The UK has funded the Thunnus UK project, as part of the ICCAT Grand Bluefin Tuna Year Programme(GBYP) research activities, to provide a baseline understanding of the ecology of Atlantic Bluefin tuna (Thunnus thynnus) in waters of the British Isles. This work is on-going.
The IUCN (International Union for the Conservation of Nature) revised their Eastern Atlantic Bluefin tuna entry from "endangered" to "near threatened" in 2015. This reflects the improving state of the stock but underlines the continued need for a cautious approach to its management.
In 2017, ICCAT received advice from its scientific committee (the Standing Committee on Research and Statistics, SCRS) that the stock was increasing and unlikely to be subject to overfishing. However, these assessments and stock projections are acknowledged by SCRS to include a degree of uncertainty relating to a number of biological and ecological aspects of Bluefin tuna life history and the models used.
