Long Island waters have seen yet another massive fishkill, with fish seen floating near the shores of Glen Cove Creek - many dead, but others just fighting to survive. "There's a lot of fish in a small area, they use up the oxygen and they're fighting to breathe," Lt. Lawrence Demmler, of the Glen Cove Harbor Patrol, said. Demmler estimates well over a hundred thousand bunker fish have crowded the creek this year, opening their gills and mouths to desperately try to draw in more oxygen. Dozens of fish have already died, with some sinking to the bottom. Others have floated to the shore to be picked apart by seagulls, CBS2's Elise Finch reported. "They're just waiting for an easy meal," Demmler said of the seagulls. "They've been doing it all morning." This recent die-off follows another massive fish die-off earlier this year on Long Island's East End, where tens of thousands of dead fish were seen floating along the shores of the Peconic Bay. Environmentalists believe the Glen Cove die-off is being caused by more than a lack of oxygen in the water, WLNY TV 10/55's Long Island Bureau Chief Richard Rose reported. "We could do more testing of the water, we could understand the science better of what's happening and we could put into action keeping people accountable," Adrienne Esposito, of the Citizen's Campaign for the Environment, said. Esposito said the state needs to go after tankers spilling oil in the Long Island Sound. She also said the state should target leaking shoreline septic tanks and the excessive use of pesticides and fertilizers that decrease oxygen levels.