I rarely say anything about television shows; this is because I rarely watch them. I did watch one recently which, frankly, disturbed me:
In case you haven’t watched the new Animal Planet series “River Monsters,” allow me to get you up to speed. This guy is a biologist, I suppose; that’s what it says here, anyway. I have a few scruples with the most recent show in which bull sharks were discussed. I hesitate to be critical of most shows on Animal Planet, however, this one, frankly, irritated me on many levels. It was stated that bull sharks are living permanently in a river system. I have serious issue with such a claim for a number of reasons. The first of which is the physiological demand required to maintain osmotic balance. Bull sharks must produce twenty times more urine (and far more dilute) than those in saltwater. Additionally, they must lower sodium and chlorine ion concentration (~20%) in order to survive in the low salinity environment. This is very metabolically demanding.
Knowing this about bull sharks, I would hesitate to make any claim about bull sharks living and reproducing in fresh water. What is far more likely is that these sharks travel in and out of fresh water during their lives. On the show, I noticed a fishway. If you are not familiar with this, either. Read up on the Lake Nicaragua sharks.
I would expect an organization such as Animal Planet to at the very least look on Wikipedia prior to airing something. Then again, similar channels have been running shows with little or no scientific consensus or discussion for years now.
This is not all I have to add to this-I have much, much more to add; unfortunately I do not wish to devote any additional time to the matter.