Robert Krulwich has more to say on topics we referred to in several links and observations about dwindling fisheries.  Is it just a matter of perception?

Yes, there are more and more people on the planet, and yes, there are fewer and fewer fish in the sea, but do we really notice? After all, fish live in water and we live on land; so we don’t mingle that much. If fish were sparrows, we might see a dramatic decline, but who misses what they don’t see in the first place?

Click the image to go to the full line of reasoning.