Curt-
5 years was about how long it took to fall apart after the State stopped us from hauling fry all over the system. It worked and it worked well.

BUT-and it is a big Butt---
Back in the 70's when we were doing this, the fry were from hatchery stock, that stock came from the biggest fish each season and some fry came from brood stock. (Fish we went out and caught, put in tubes and matured) before taking the eggs/sperm and then put the brood back in the river.
The hatchery was clean and the pens were well maintained and only the best fish were used, the runts or brats as many call them were recycled back down stream to be caught.
Once the State put a stop to it, budgets were cut and the hatcheries went down hill and they took every egg no matter what the condition or size of the fish. There was a time when hatcheries worked well and put out quality fish.
I know that for the purist, it does not matter and only natives mean anything, but back then you could not tell the difference between hatchery and wild fish until February when the big ones came in and most of the hatchery fish were not an issue.
I shared a picture a few weeks ago of a 19lb. clipped Snoqualmie fish from 1976, I caught 4 that year that were in that class, with the largest right at 22lbs. The hatchery haters cannot deny those fish were big and strong and every bit as nice as a 22lb. native and without the clipped fin, you would never have known!
The State messed it up all based on politics and budget.