A valid question would be whether those sample hatchery smolt actually experienced a higher attrition rate than (a) other non-surgically altered hatchery smolt released at the same time and (b) wild hatchery smolt outmigrating at about the same time. And if not, what is the variation and why?

Where this is going to get really interesting is when the Orca folks push harder for Chinook to feed the Killers. Maybe pitting Orca lovers against seal lovers. Wow, I'd pay to witness that face off! Just hope we don't end up paying for Chinook and then being told sorry, need'em for the Killers.