There's an analogy I sometimes use to explain the problem of overfishing.
Imagine you are in a car hurtling at full speed down a hillside towards a cliff. Your foot is fully down on the accelerator. You have four options. Keep the foot down and plunge to your certain doom. Slam on the brakes and try to stop before you reach the cliff. Take your chances and jump out of the moving car. Or take your foot off the accelerator and just hope you slow down in time.
Applying that analogy to Atlantic bluefin tuna, what needs to happen is the brake-slamming option.