There isn't enough known about the open ocean migration of specific stocks of salmon to accurately predict where they are going to be and precisely when to target them.

So do foriegn fleets target salmon that originate in the U.S. and Canada? They certainly do outside the 200 mile limit (international waters) and they probably wander into the 200 mile limit occasionally to grab whatever salmon they can get their nets around. However, it's highly unlikely or even impossible to target, say Columbia River spring Chinook salmon in the open ocean. That's not to say foreign fleets don't catch them. They probably do. But since scientists aren't even sure where they go with any precision, I wouldn't expect any commericals guys to either. But it does raise the question of why is the springer run so small on the Columbia when all the pre-season signals pointed towards a strong run?