Following from several of the superb and well-informed comments to the post below, I recommend a piece in today's Indie on the rape of African fish stocks.
It's not perfect. The author for example in writing "Fishmeal plants in Senegal typically produce just 200 kg of fishmeal
powder from one tonne of wet fish, protein that would otherwise be
destined for human mouths in one of the hungriest regions on earth." clearly has little idea that what fishmeal plants actually do is to de-water the 80% water content of milled fish prepatory to transport.
We're far from the 1970s, when battery eggs in the UK had yolks glowing bright orange with Xanthophyll and tasting strongly of fish from the crudely compounded feeds. Now the fish are fed to factory cows in vast, automated robotic farms using mutant and deformed Fresians as living milk plants, and technology has made the milk utterly tasteless as well as pulversing the fat globules down to a size in which our tongues not only cannot taste the rotten-fat taste of sour milk but the milk takes three times as long, once rotten, to de-emulsify. So filling stations can sell milk that can be six weeks old by the time you pour it over your cornflakes.*
And of course EU farmers maximising their CAP incomes can supplement the cows' staple feed of fish with silage or hay cut from the deserted and wildlife-barren meadows surrounding the cow plants, so long as they soak them in enough nitrate fertilizer, pesticides and herbicides.
* Until you come here - where milk is fresh, local and just pasteurised and tastes like milk tasted when you were a kid (not the free 1/3 pint stale vomit-flavoured wastings that were sold to schools but the real stuff your mum bought).