plenty more fish in the sea?

I am a new subscriber to 43 things.
I read some comments by people who like me have committed to reducing their environmental footprint. One comment referred me to this excellent article in the Guardian by Lucy Siegle

Both Tone and I have been vegetarians in the past. I don't eat any mammals anymore. I often eat vegetarian meals and try to buy organic food. I find organic food very expensive and hard to come by locally. We have been eating more fish recently - for health reasons as well as for the taste. We have found a fantastic fresh fish stall in Tunstall - the owner buys fish from Liverpool dock every morning that he opens. The provenance of all the fish is known and labelled - e.g. Iceland, Faroes etc. However I'm certain much of it is farmed although I have not asked. He does sell organic salmon. (Having said that the Soil Association have decided to label farmed fish as organic - which makes a mockery of the idea it seems to me. This could mean that the organic salmon sold by the fishman in Tunstall is farmed.)

The article has concentrated my mind on a few things. I am shocked to discover that farmed fish is often fed on wild fish - 3 tons of wild for every one ton of farmed. Farmed fish is ecologically unsound. I am concerned about over-fishing. I find it hard to conclude anything other than only buying organic wild fish, if any at all.

Lucy Siegle concludes like this -
"Although I now understand how hard it is to turn a profit from ethical fishing, the alternatives are unappealing. There's still no overall strategy to maintain and develop ocean ecosystems. Partial fishing hasn't worked, total allowable catches are set too high, prone to abuse and do not allow species to recover.
I'm not given to breaking into restaurants to rescue crustacea, but I can't get over the thought that ranching a large oceanic predator (which essentially means keeping it in a cage) is wrong. Add on the problems in the supply chain, doubtful provenance and food miles involved in shipping certified fish and I arrive at the conclusion that I no longer want to eat it. I will not, therefore, be following the FSA's guidelines on two portions of fish a week, and I no longer subscribe to the view that there are plenty more fish in the sea. There aren't."