Giving up eating tuna?

A lot of people ask about the sustainability of eating tuna.
With the new Sushi food habits worldwide, people are more aware about this fish.
It always depends on which tuna species we are talking about.
There are several...from different oceans, different stocks and caught in different ways.
Above all, tuna is a top predator.
It is the same as eating a lion.
Nowadays Portuguese eat more tuna than ever.
It is one of the most consumed fish.
Why?
Because it is canned, available and easy to prepare.
The stocks are one problem but there is another one:
tuna accumulates bio-toxins, as mercury.

Turns out that about three-quarters of it comes from coal-burning power plants; it dissolves in water, where micro-organisms convert it to methylmercury, a bio-available and highly toxic form that builds up in fish. 
The longer a fish lives, the more mercury builds in its flesh.

So if environment is not enough, a health message seems to be an efficient way to communicate to reduce fish consumption.