How Salmon Adjust from Fresh Water to Salt Water, and Back Again

In the salmon sequence of Living Waters: Intelligent Design in the Oceans of the Earth, one of the stories documentary producer Lad Allen wanted to tell was about osmoregulation. That is, the control of body fluids and ions during the transition from fresh water to salt water and back again. This is an important transition in the life of every Pacific salmon.

Allen's crew researched this fascinating topic, but in the final cut they only had time to mention it briefly, stating, "In preparatio...