I have not personally, but I have stayed up to date on the science.
One thing you need to really be careful of is that seals and sea lions, for example, eat an enormous amount of hake, and hake is a fish that preys on juvenile salmon. Once you start messing with the natural order of things.... We also have a growing transient or big killer whale population that are currently feasting on these pinnipeds, so it's a dangerous path.
As was mentioned earlier, if you have five stressors on your salmon and you can remove a couple of them, you are way out ahead. We know that wild salmon are not surviving exposure to salmon farms. They're not surviving it anywhere in the world. This is an impact that not only can be removed, but it can be put somewhere else. If you want to go and shoot all the pinnipeds, you may well unleash a greater problem, which are the hake and other species that are happy to prey on these juvenile salmon. It's a tricky road to walk.