If FF's are having an effect on the wild salmon populations then it doesn't really matter if we have an exact % or ranking on what that effect is. Ecosystems are incredibly complex and to think we can rank factors that influence wild salmon populations is unrealistic if not impossible and precisely WHY the FF supporters ask for this level of certainty... so that they can go about business as usual while the science continues to pump out findings that FF are harmful but not being able to quantify exactly what impact they are having to 2 decimal places
If FF's had ZERO (or close to it) impact on the environment or even if they had a small impact and made up for their small impact with financial contributions to improve the environment/province I would be on board with them. The reason I can now be categorized as an 'anti-FF' is because they have a 'more than ZERO' negative impact on the environment (including wild salmon) coupled with the fact they are subsidy-receiving, foreign-owned, evidence-hiding corporations who are not looking out for BC's environment as a whole or wild salmon specifically.
I will grant you that wild salmon face impact from many other causes that open-net pen fish farms. Human impacts are top of the list, with habitat degradation probably at the top of 'my' list. Habitat in the nearshore environment, specifically, is a large problem as estuaries and inlets have been hardened/developed to the point where this important habitat is severely worsened. Increasing ocean SST and acidification (climate change issues) are also clearly have substantial negative impacts. Overfishing in certain areas/species is not helping with the overall sustainability of wild salmon populations either. So what can we do? Well, start with some short-term solutions to tackle those issues negatively impacting wild salmon.... namely fish farms. Stop new tenures ASAP, move them off migration routes ASAP, hold them accountable for disease/waste and work to move them on land in a timely manner. Land-based operations have their own issues but they will help eliminate many of the current impacts the open-net pens are having on wild salmon.