I'm not a fisherman, but I do like to eat salmon. I haven't met one fisherman who felt his life has been enriched by sea lions--especially those who chase the salmon up the Columbia and some of the tributaries.
As a kayaker, I feel much more enriched when the sea lions are out in the Pacific, which is "the sea" where they belong. Hey, I would even concede the mouth of the Columbia to these beasts, but I will never believe that they are doing anything but harm when they transgress beyond the saltwater.
I have witnessed many times the malicious killing of salmon, sturgeon and other species, just for the sport of it, by sea lions--seemingly when their bellies are full.
PhilS, I hope you're right that sea lions don't pose a danger to kayakers, but I know for a fact that the same does not apply to dogs that are swimming where sea lions are present. Last year, a black lab was killed by a lion as it was retrieving a stick that its master had thrown in the river.