An interesting report today. I suppose it's not news to realise that we have an effect on the world's oceans, I was just surprised at the extent of man's impact.
This study is perhaps more comprehensive than others as it combined a variety of environmental factors rather than just focusing on, say, fish stocks. More details here. The UK comes out with a very poor score.
If you have time, watch the fly-through on the first link above. And if you're really keen/bored count how many times the presenter says "activities". Lots.