NGO Best for tuna
When it comes to applying restrictions, there are many (profit and non-profit) organisations more than willing to support new rules.
The BIG question is, how can fishermen survive all these restrictions, with prices @ rock bottom level (which can only be compensated by catching more).
The canners, who proclaim sustainability, import their tuna form all over the world and try to stretch the limits and buy pre-cooked loins (caught by non-ISSF compliance fleet) to avoid following their ISSF-regulations.
Tuna buyers should not buy immature tuna (especially Skipjack < 1,5 kgs.) at any extend. In West Afrika – mainly Ivory Coast – is a market for small size Skipjack, but this is not the case in other oceans. It will make the boatowners reluctant to let their boats fish on all tuna that moves!
For the boatowners, if you keep landing small Skipjack, the buyers/canners will always find an excuse to pay lower prices too for the other tuna which is mature and more valuable.