Tag-a-Giant are discovering lots of new things about the tuna's previously hidden lives. Firstly they have found that the fish are as faithful to their spawning grounds as salmon are to theirs. Over 90 percent of Bluefin tuna spawned in the Gulf of Mexico return there to spawn. And the same is true for the population of Bluefin tuna which spawn in the Mediterranean sea.
Scientists have also found that there is far more mixing between these two populations of fish than previously thought. Although the Western ones are faithful to the Gulf of Mexico for spawning - and the Eastern ones show site fidelity to the Mediterranean - in between times, when the fish are out foraging for food, they mix a great deal. It seems that each Bluefin is potentially using the whole of the Atlantic ocean as its feeding ground.
The reason this is so significant is because of fish quotas and trying to set them correctly. Counting Bluefin tuna off the east coast of the States and setting a fishing quota for that number of adults could be nothing short of disastrous: a good proportion of those fish may be of Mediterranean origin, so the numbers could seem artificially high. At a time when Bluefin tuna population numbers have dropped dramatically and they are of the utmost conservation concern, this research on where the fish go could be the key to securing their future.
For more information, go to www.tagagiant.org