It was news to me that fish don't metabolise those fabled fish oils — DHA and EPA — themselves; rather, these come via the food that the fish eat. The oils are made by single-celled algae which then pass through the food chain before being consumed by salmon, etc.
Thus it is that farmed salmon have to be fed on smaller fish such as anchovies if they are to work their nutritional magic on us. About 10% of all fish caught is used for this fish food.
But now there seems to be a way to avoid having to do this, and to avoid all those heavy metals that unfortunately lurk in these smaller fish. The problem is that the alternative feedstock is a GMO. A recent Economist carries the details of this development.
So, is this a no-brainier, or a no-hoper? It's certainly another test for those crusading folk who wake up each morning knowing they're agin GM in all circumstances and at all costs, and go to bed at night even more convinced. If they bother to think about it, they'll find they're caught on the horns of a trilemma.