A so far unknown spawning area of the Atlantic Bluefin Tuna (BFT) may be off Madeira. This is the result of a now published DNA study on the origin and return to the “birthplace” of almost 1,000 BFT in the Atlantic. According to the study, about 83% of the tunas off Norway originate from the spawning grounds in the Mediterranean and some from the Gulf of Mexico. However, 13% of the tissue samples could not be assigned to either of the two traditional spawning grounds!
The following diagrams show the origin of the Bluefins. Yellow is of Mediterranean origin, purple is fish from the Gulf of Mexico and grey is tuna of unknown origin.
According to data from satellite tags, scientists are now suggesting that a possible spawning area could lie off Madeira. Big BFT are therefore there during the spawning season! Source: Rodríguez-Ezpeleta, Naiara, et al. Determining natal origin for improved management of Atlantic bluefin tuna. Frontiers in Ecology and the Environment (2019).