Yep - I caught my black marlin trolling a spread of live 8 lb bonita for bait. Had a number of 50 lb yellowfin tuna bit in two while fighting them. Had a ten ft hammerhead eat a five ft barracuda we were fighting. Almost everything in the ocean is bait for something else.I used to work as an engineer for the long island fossil power plants. Used to fish the plant discharges lunch time and after work. The outflow would be 10 degrees warmer. Also, some dead baitfish would be in the discharge. Was litterally a buffet table for fish in the area. Was a real lucky guy back them.
Typical freshwater fish you catch is about the same size you use as bait in the ocean. Certain things you see in the ocean folks dont even believe. Like a bluefish blitz on bait. The thousands of baitfish can make a wave of their own. OR they go on shore to avoid capture. Had a few bunkers go down my waders over the years. Seeing shark play with sea lions is a sight too.