Thanks Divers for adding some perspective..

You guys are absolutely correct! For you it isn't dark, but for a salmon it is a different story... My bubble... I guess I needed to clarify a little better...

... light as a (King) salmon sees it. His world is near dark at 30 feet because of the way his vision is set up to absorb and deflect light. And it is extremely poor vision (acutity) for that matter too. This is the main reason he hunts for food via sound along is lateral line. If Kings had to soley rely on sight, we would have some small, thin fish! For salmon, it would be very similar to someone walking in to a dark room with a little light creeping through a crack in the curtains. You certainly could see, but how about distinguishing colors?

I threw those numbers (feet) out there because this is the general consensus on where it is believed a (King) salmon threshold begins when it comes to light sensitivity. He won't break this threshold unless it is absolutely necessary. E.g., to feed.

I pose this .... With sunlight starting to decrease in water at the 120-150 foot range, and with salmon being light sensitive, wouldn't that mean we need to fish a lot deeper than the normal 60-150 foot range for blackmouth? Or ocean fishing at 40-80 depths?

Other species of salmon have different thresholds. The main reason would be migration routes to the sea. Silvers, chums, pinks, sockeyes all travel close to the shoreline in shallow water when migrating.

One of the reasons we fish suspended for returning Kings at depths greater than 40 feet is there routes... which is below their sunlight intensity levels. You certainly can fish shallower at periods of darkness or "gray light." Gray light is just prior or after twilight. You can even fish off the mouth of the Pew all day at 30-60 feet because of surface silt blocking the light.

I couldn't imagine trying a catch a salmon with a visual acutity of a human! Could you? A salmon's vision is 180 degrees out from our vision...