I actually don't eat seafood. Well, Tuna on the odd occasion, but basically that's it. Unfortunately my shopping habits will not make a difference.
I do agree with Steve that apathy and money are the keys, but I kinda look at them a little differently. I think people in a general sense care about the environment, they don't want to destroy the oceans through bottom-trawling. They probably don't know or feel they cannot afford to care. 80% of the worlds population lives in poverty. We have 6 billion people on this planet that we have to clothe, feed and provide shelter. In Thailand they used (still do?) to use dynamite to catch fish as it was far more effective than trawling! How insane is that?! Coral reefs were being blown apart to catch fish. I think people are far more pre-occupied with getting dinner on the table than where it came from. I am NOT one of these - I just like to point that out. We can argue how can people ignore what is going on, but if you ask the everyday person (in developed countries) what they care about it is usually health, education and their personal chequebook that occupies most of their time. The only way to get bottom trawling banned is to get the pollies to care. The only way the pollies are going to care is if people care. The only way to make people care is ? Actually, I have no idea. If I did I would probably be in great demand for pollies PR services.
I definately endorse Steve's stance on one person making a difference through the signature or supermarket stance. By setting examples we can possibly influence those around us. I'm afraid it will take too long to change enough habits to save species. We must keep the issue in the public eye. The media is powerful and influential. To change a mass of habits, you need to appeal to the masses. However, we just don't want to be 'another environmental problem'. Any thoughts would be great.