The chum salmon are almost impossible to see (or photograph) since their colouring is so similar to the river's gravel bottom.
This short video makes them a bit easier to spot:
Click arrow to play video
In the end, after spawning, they will end up as food for seagulls, bear, and raccoons.
Once whatever's left starts to rot, the eagles pick up the scent and will swoop in for the leftovers.