I read an article on a study conducted a couple of years ago by the Canadian Dept. of Fisheries and Oceans. I for the life of me can't remember the name of the river. Their biologists analyzed a salmon to determine the mineral/nutrient level(not sure what species). They determined that nitrogen was the largest component. They manufactured a charcoal briquette comprised of the same amount of nitrogen as a salmon carcasse(these were time release to mimic the natural decay of a salmon). They dropped these briquettes in based on the number of salmon that usually spawn . When the progeny of the actual spawners out-migrated they trapped the fish and measured the smolt. Based on previous out-migration studies these particular smolt were much larger and healthier than those of the previous studies. Canada is looking at this as a short term aid(not a solution) towards recovery. As far as the lower parts of the river is concerned, out-migrating fish only hang around short term so I don't think this would be a big issue. Besides, most of this activity as well as carcass seeding occurs in the middle upper reaches of most watersheds.
I like the idea as long as it is used to jumpstart mother nature and not as a cure all.

Chumcatcher