The three species of bluefin tunas can be found throughout the world's oceans from the equator to sub-polar seas. A suite of physiological adaptations has allowed bluefin to range widely, exhibiting some of the greatest individual ranges of any fish. Some fisheries targeting bluefin tunas have been operating since ancient times, mainly supplying fish to small, local markets.
Recent changes in the globalization of fish markets, coupled with industrial-scale fisheries and a high price in the global sushi market, have driven exploitation of bluefin tunas beyond sustainable levels. As a result, global populations have declined considerably, in some cases to as low as 3 percent of unfished population levels.
The threat from overfishing is compounded by life history traits, such as slowness to reach maturity and a long life span, which means rebuilding depleted populations will be a lengthy process. Greater knowledge of the underlying biology of bluefin will allow scientists to understand how much fishing pressure is sustainable and how fast populations can recover. Ultimately, the recovery of bluefin tuna populations depends on the willingness of managers to enact scientifically sound management measures and on the ability of governments to enforce agreed upon rules.