Unusual Presence of Bluefin Tuna in the Gulf of Aden and in the Indian Ocean

The unusual presence of an adult bluefin tuna individual, fished off the coast of Yemen in May 2021, stimulated a discussion among several fishery scientists. This is the third event in the Indian Ocean concerning vagrant adult bluefin tunas in recent times and this paper is proposing various hypotheses about the possible species concerned. The most probable seems the Pacific bluefin tuna, but this is not the only possible option, at least for the latter event. This paper also reports some old catches of bluefin tuna juveniles between the Gulf of Aden and the Arabian Sea, in the NW Indian Ocean. All these events should induce initiatives by the IOTC for improving the knowledge on recent distribution changes of bluefin tunas in the Indian Ocean.