There's a foul odor coming from the American River that smells disgusting but is natural.

That smell is Chinook salmon.  They moved up river to spawn, and of course, after they've done their deed, they die.  Now, because of low water levels, the smell is much more noticable.

Families out by the river got a nature lesson first hand when they visited.

The Department of Fish and Wildlife says this is all part of the natural life cylcle of salmon and the smell should only be around for about another month.

PHOTOS: Salmon Carcasses Line American River