Porpoises
The Harbor porpoise is actually known for its close hunting of herring. Harbor porpoises also are called herring porpoises among fishermen. Harbor porpoises are found in North Atlantic oceans, like the Gulf of Maine and Bay of Fundy. In the summer, herring moves inshore in large schools. The porpoises use echo location to find and follow herring for a fishy feast.
Seabirds and Puffins
Herring larva and juveniles are common sources of food for seabirds. These birds dive in and hunt herring from the skies. Herring gulls actually do not actively hunt herring, though they have been known to scavenge a fisherman's herring. Atlantic puffins, razorbills, common terns and Arctic terns love herring. These birds actively hunt herring in the Gulf of Maine.
Seals
Herring travel in large schools. This schooling behavior detects incoming behavior, but it also allows for large marine animals like seals and porpoises to take advantage. Harbor seals and gray seals also enjoy hunting herring schools. With their vibrissae whiskers, seals sense herring and dart into schools to get their catch. Harbor seals often get trapped in fishing gear since they closely hunt the fish.
Other Predators
Juvenile, larvae and adult herring are major sources of food for cod. Sculpin also eat herring eggs. Other fishes that enjoy herring are dogfish, hake, tuna, bluefish, pollock, striped bass and some species of sharks. Killer whales also have been known to drive schools of herring into shore and up to the surface to feed.