Here's Andy Thomas' presentation from last year's (2009) annual WTT get together in Yougreave, Derbyshire.

There are two 10 minute videos (part 1 and part 2) with a short gap during which video tapes were changed. Many common questions, comments and statements that we come across with respect to stocking during our day to day work with the WTT are tackled.

Part 1
YouTube- Andy Thomas and WTT position statement on stocking_1.mp4

Part 2 (including just a few of the big practical problems with wild brood stock egg stripping)
YouTube- WTT Position on Stocking_2.mp4

Basically, everything that applies to triploid stock fish also applies equally to diploid stock fish. Its just that triploids won't interbreed with the wild fish and reduce their ability to survive and reproduce.