How to Tell If You're Poisoning Yourself With Fish

When the halibut on my hook breaks the surface, writhing in a splash of seawater off the coast of Bolinas, California, I am thinking less of this fish’s fate than of my own. Considering that I plan to kill and eat it, this might seem cruel. Yet inside the fat and muscle cells of this flat, odd-looking creature is a substance as poisonous to me as it is to him: methylmercury, the most common form of mercury that builds up inside people (and fish).

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