Walls of Death?

I was reading this article arguing against a "vegetarian diet" and came across a this quote about current fishing practices:

...With the North Sea almost fished out and now highly regulated, third-world fishermen, hungry for foreign currency, are plundering their own declining stocks in other unregulated oceans.

With fish becoming increasingly difficult to catch in quantity, modern fishermen and their equipment are becoming increasingly sophisticated. Cornish fishermen are using four-mile-long drift nets to catch tuna in the northern Atlantic. The nets are called 'walls of death' because of the numbers of dolphins and other unwanted fish they catch. The Japanese fish for tuna with lines up to sixty-five miles long with thousands of baited hooks. In the North Sea, trawling does more damage than pollution.

Fish are very good at renewing themselves – if they are allowed to do so. But few will let them. Despite international agreements and quotas, in the northern seas, no-one, with the possible exception of Iceland, is managing their fish stocks properly and the problem of over-fishing is spiralling out of control.

I'm not ready to give up my vegetarian lifestyle. After being a vegetarian since 1995, I don't even like the taste of meat, or fish. I can't stand the thought of factory farming...