Isotopic analysis of the ear bones of Atlantic bluefin tuna (Thunnus thynnus) has shown, for the first time, that an ocean-roaming fish returns to where it was born before spawning.
Jay Rooker of Texas A&M University in Galveston and his colleagues studied the ratio of oxygen-16 to oxygen-18 in the otoliths of these fish. Their findings indicate that 99.3% of the bluefin tuna spawning in the Gulf of Mexico and 95.8% of those spawning in the Mediterranean had swum back to their natal waters.
Populations of the fish have seen a precipitous decline from overfishing; the authors hope that their results will contribute to the species' future management.
About this article
Cite this article
Zoology: Boomerang bluefins. Nature 455, 710 (2008). https://doi.org/10.1038/455710d