The Wash

Great article here from the Southern Fried Science website, simply titled:  The Ecological Disaster that is Dolphin Safe Tuna.

In brief, the way they "used" to fish for tuna was to find large swarms of dolphins, and follow them to where the tuna was.  This worked well (because dolphins are great at finding tuna), but obviously some dolphins were caught, and killed at the same time.  People like dolphins so this wasn't acceptable, and a change was needed.

Now they fish for tuna by leaving floating objects in the sea, which attracts a large variety of fish species including tuna.  This means that less dolphins are killed, but more OTHER sea life is netted at the same time as tuna.  This includes animals that are either endangered, or close to it, like sea turtles and sharks (dolphins aren't and have never been an endangered species).

The simple answer would be to stop eating fish all together, but this is not really a reality for most, as  the author mentions in the comments on the article:

According to the U.N., something like 2 billion people get at least 1/3 of their daily food intake from the sea, and many of these people are desperately poor and don’t have the option to eat something that is more expensive but more sustainable. It doesn’t seem right to me to tell people who have known starvation that they aren’t allowed to eat something.

Food for thought.