Bait Fish?

Lately the "bait fish" I've been seeing at my go-to area 10 beach have been young salmon in the 6-10 inch range. They're jumping all over the place, skipping across the water, etc. Are they the bait, or are they pursuing smaller bait (amphipods and the like) and bursting the surface in their zeal, sort of like trout going wildly after salmonflies? As far as I can tell, there's nothing chasing these fish, at least nothing I can see. And big silvers are NOWHERE in evidence.