Whale
The IWC has designated two whale sanctuaries: the Southern Ocean Whale Sanctuary, and the Indian Ocean Whale Sanctuary. The Southern Ocean whale sanctuary spans and envelopes Antarctica. The Indian Ocean whale sanctuary takes up all of the Indian Ocean south of 55°S. The IWC is a voluntary organization, with no treaty. Any nation may leave as they wish; the IWC cannot enforce any law it makes.
North Atlantic right whale
Parts of the western group, especially for those seen regularly in the Gulf of St. Lawrence, display different migratory or calving routines than other whales and these are so-called "Offshore Whales". There could be various areas along or off the west coasts where could have been frequented by whales potentially and might be re-colonized in the future such as Quoddy, Eastport, Plymouth Harbor, Sagamore Beach, Island of Nantucket, Florida Bay, Pamlico Sound, Gulf of Mexico (as far as to Texas), Bahamas, Long Island Sound and vicinity to New York City, the mouth of Potomac River, Delaware and Chesapeake Bay, the mouth of Altamaha River, Cape Canaveral, Sebastian Inlet and around Melbourne, and so on. As the population grows, it's also highly possible that more whales would start using rivers or river mouths, shallow estuaries, smaller inlets or bays. Whales have already seen repeatedly at various of these such as Indian River Inlet, Delaware River, Cape Cod Canal, Jacksonville Drum, and so on.