Jim I love ya... but the return rate does not lie.
It's flawed methodology. This seems painfully obvious to me. Growing them in pens is a mistake. They should hatch them then release them immediately. Obviously fish that grow up in pens lack the skills necessary for life in the wild. Larval seabass develop in the plankton for about five weeks. They should release them in that planktonic stage in areas that they are known to be found so they then develop naturally with the instincts they need to survive long term. It would save time money and have a much higher success rate.
Fish grown in tanks or pens only understand tanks or pens, they imprint to that environment, this is why the tank grown butts do not know how to properly bury themselves.
I appreciate the idea and all the effort but to succeed with a hatchery they are going to have to release those fish into the wild ocean in a larval non imprinted stage.