Radio or acoustic tagging to demonstrate progressive inland movement up the system.

Extremely expensive and labor intensive.

AK just spent 700K on the Kintama project for UCI.
"Let every angler who loves to fish think what it would mean to him to find the fish were gone." (Zane Grey)

"If you don't kill them, they will spawn." (Carcassman)

The Keen Eye MD
Long Live the Kings!