Kings surfacing in deep(er) water

[RH93]

First off, this is the latest I've kept the boat in the water, so maybe what I'm seeing is normal.

 

Was fishing in 100' of water last night just off of Sandy Creek. Every few minutes I would see kings surfacing. I'm used to seeing it in shallower water, and in the estuary. Just find it abnormal to see it that far from shore.

The last few weeks I have been fishing in deeper water, and was regularly seeing marks on the sonar going from the bottom of the lake all the way to near surface, in an almost straight vertical line. What's the science behind kings coming to the surface and intentionally coming into warmer surface water temps, when cooler water is available? 

 

 

[Silver Fox]

All summer off Sandy I was seeing smaller kings chasing bait up to the top. More than I ever seen. 

[fisherman21]

Just now, Silver Fox said:

All summer off Sandy I was seeing smaller kings chasing bait up to the top. More than I ever seen. 

I took a 15 pounder off the surface one morning in July as I was attaching the spoon to the rigger. Many mornings this summer salmon were surfacing out there