That's a really good point Martin. I live in a province with over 100 lakes, 59 species of fish (51 native), and an abundance of wildlife around those lakes.
But it's easy to assume that a lake will have fish in it...could be a dangerous assumption. There are quite a few lakes around here that just don't have fish in them. They're not all 'dead' lakes but some just have small organisms but no fish.
The bigger concern to me are the animals you can get which you shouldn't eat because of other environmental issues. Right now the government recommends eating no more than one fish from the North Saskatchewan River due to Mercury content (zero if you're under 15). One of the largest lakes in the area (Wabamun) has fish you can't eat right now becuase of a major oil spill. If you didn't know, you could ingest a lot of toxins 'living' off of those fish. It's better than starving to death but the long term damage to your body could really suck.