 to replace those at bridges. Rescuers who had helped free more than 100 dolphins from Cape Cod's shoreline say they've confirmed that mass stranding last month was the largest involving dolphins in U.S. history. The International Fund for Animal Welfare says there were two prior events in Hawaii and the Florida Keys where dolphins were observed in shallow waters, but the Cape Cod event marked the highest number of dolphins that were beached in a single stranding. 146 dolphins were involved on the Cape.