If they were jumping, it was one of two things. Insects were emerging and they were going after them. (Usually happens in a caddis hatch as these bugs take off fast.) Or the females were spawning, with leaps to loosen their eggs.

#2 son and I had an experience with the latter one day where we both got skunked while wading a river with fish leaping all around us. It got so we were laughing about it. I think I may also have heard the trout laughing as they leapt while we fished in frustration.