As someone who grew up in coastal Downeast Maine and has been lobster fishing on multiple occasions, it is my understanding that the lobsters partially feed off the dead herring used as bait. Fresh herring (freshly dead) is used as bait in the traps. Every time the trap is pulled up to check for lobsters (every 1-7 days), the old herring is pulled out of the bait pocket and fresh herring (freshly dead) is put back into the bait pocket. The old herring is tossed overboard where it sinks to the bottom and becomes food for lobsters. In a sense, the fishermen are cultivating the lobsters by feeding them. Here is a photo that I took, while lobster fishing, of herring that was used, pulled out of a bait pocket, and subsequently tossed overboard. Warning: graphic picture of dead fish. https://c2.staticflickr.com/2/1120/5100863905_1d9520e7eb_b.j...