Just because your sounder is marking schools of fish it does'nt necessarily mean they're herring, candlefish or anything else that salmon are actively feeding on. Last summer while fishing the Bubble I was marking huge schools of what I thought were baitfish and when I dropped my jig down into the schools I ended up snagging small True Cod. The whole bay was full of these small cod. I dont normally pay too much attention to the bait balls suspended off the bottom unless they are scattered, with larger fish intermingled. Or unless they are near the bottom Hope this helps.