Summary

Age 0+ spring Chinook continue to make up the largest proportion of precocious males on the spawning grounds.
Environmental conditions appear to play a large role in determining the abundance of hatchery precocious males on the spawning grounds
No detectable difference between natural production and hatchery precocious males per female on the spawning grounds
Hatchery precocious males continued to be most abundant in areas downstream of spawning locations.

Age 0+ spring Chinook continue to make up the largest proportion of precocious males on the spawning grounds.