The bluefin was identified through a hand-held genetics tool that assigned a barcode to various species of tuna in much the same way that barcodes identify products in stores.
The barcodes were assigned after a DNA sample was taken from each species of tuna and other endangered fish, the Sackler Institute for Comparative Genomics in Washington said in a release.
It may not be long before wildlife management teams could "seamlessly and efficiently identify a species and maybe the geographic origin of specific samples," George Amato, the institute's director said.
In restaurants sampled recently in New York and Colorado, the device showed 25 percent of what was labeled as tuna on sushi menus was bluefin, Amato said. The device also has been used to identify the presence of endangered whales in Asian markets and fraud in the labeling of caviar and red snapper.