Menhaden — also known as pogies or bunker — are small oily fish that feed nearly everything in the Atlantic. They are the foundation of the East Coast’s marine food web, fueling striped bass, bluefish, tuna, whales and seabirds. Yet each year, a single industrial operation hauls out hundreds of millions of pounds of them — not to feed humans but to grind them down into oil and meal for aquaculture, supplements and animal food, much of it for export.