Eating fish is good for you, it's low in fat, and oily fish in particular are high in omega-3 fatty acids, or the "good" fats that the human body isn't that good at making. But some fish, tuna in particular, are also high in dangerous mercury, that they absorb from the water and the things they eat. So it's possible to eat too much of a good thing. New research shows that efforts to clean up the oceans may also be cleaning up Atlantic tuna. VOA's Kevin Enochs reports.