This is probably the most destructive method of fishing ever thought up. Basically, what happens is you get an absolutely massive boat, put out between 2000-3000 meters of net in a big circle around a FAD - a fish aggregating device. Now, these FADs are placed out in the open ocean, and attract small bait fish - herring, sardines, mackerel, all that. In turn, this attracts tuna. This, in turn obviously attracts al kinds of larger predatory aquatic animals - sailfish, dolphin, giant manta rays, sharks. As the net encircles the FAD it scoops up everything within it. Yes, even the dolphin, sharks, manta rays. Everything.
Most of this is thrown back into the sea - dead. A lot of sharks often have their fins cut off before being thrown back.
What can you do to prevent this? well first off, make sure you buy canned tuna that’s pole caught - in England, brands like Sainsbury’s and Marks & Spencer’s are very good. Brands like John West however still use destructive methods like this, so please try steer clear of them.
I would love to see the oceans outlive me.