The marine net pen releases of FCS were never very successful and were not in production during the heyday late 70's and early 80's that you and I remember. Freshwater releases of FCS yearlings were driving the "success" of those fisheries. Certainly some of those FW releases where from "net pens" like the ones in Percival Cove, but others were just normal hatchery releases. I only put quotes around "success" because that success was driven by at least one other factor besides survival. For instance, the minimum size limit for resident Chinook was lower then and a successful trip with limits of smaller resident fish turned into unsuccessful trips with nothing but shakers once the size limit was raised. It's been too long for me to remember how low the size limit was in that heyday, but when that treaty/non-treaty allocation imbalance that was mentioned above occurred, one of WDF's responses was to raise the size limit, thus lowering the non-treaty catch. I know that it happened at least once, going from 20" to 22", but I believe it actually happened at least twice, arriving at the final limit. [CM and SG might remember] If you looked strictly at survival, (which took some time, since WDFW simply assumed the marine FCS programs and some other new FW programs would be successful and didn't bother tagging most of them), entire programs accounting for 10's of tons of fish released contributed only 10's of actual fish in the catch. Again, pay attention to the time frame when the marine net pens switched to FCS and other programs started to tap into the PS enhancement fund money. It was not during the heyday that you remember. (BTW, WDF's other response to deal with the allocation imbalance was to pay for increased releases of zero-age FCS in areas where they would increase the treaty catch, primarily in the S. Sound region of origin, since that is where the imbalance occurred.) [Again, CM and SG, check for accuracy.]

Edit: After I read this, I remembered that during the heyday, the yearlings raised in Percival Cove were actually allowed to swim freely around the cove. It wasn't until fish eating birds discovered the easy picking there and the hatchery folks couldn't continue setting off fireworks to discourage them just below the Capitol, was the production moved to net pens in the cove.