What's Eating My Herring?

[STEVE IN MASS]

Have made a number of trips to the Ditch the past few weeks. Each time, aside from throwing about everything I could think of, I drifted dead herring, both whole and chunks.

Kept getting small taps. Many times, the herring would come back with a bite out of it, about the circumferance of a quarter, whether it be whole or chunked.

So, what's hitting it? I thought it might be those Bergalls, or whatever they are, but thought the size of the bites was a bit big for them....

At times, the hits were a bit more than taps, but not so hard as to be bass or bluefish.....

Any ideas?