Seasons, populations and approach rules are quoted from NOAA Fisheries, NOAA National Marine Sanctuaries including Stellwagen Bank, Gray's Reef, Monterey Bay, Channel Islands and the Hawaiian Islands Humpback Whale sanctuary, the National Park Service, Oregon State Parks, California State Parks, Maine Department of Marine Resources, New York Department of Environmental Conservation, Georgia Department of Natural Resources, the Florida Fish and Wildlife Conservation Commission and the Washington Department of Fish and Wildlife. Federal material is public domain. The monthly observation counts come live from the iNaturalist API, which is open and carries no commercial restriction, and are used as aggregate counts only.