The Berry Islands chain represents one of the 22 bank systems of the Bahamian archipelago, essential fish habitats comprising juvenile nurseries, foraging and sheltering grounds. The 12,000-feet Tongue of the Ocean surrounds the southern cays, offering a large variety of marine life that makes these islands great for marine eco-tours. Three blue holes here include one on Chub Cay that is part of the Southern Berry Islands Marine Reserve, an ecologically sensitive area, and one on Hoffman Cay, whose only living inhabitants are said to be oysters. There are also hundreds of acres of fertile black and red mangrove shrub wetlands, which support a variety of bird life. One of the private islands, Little Whale Cay, was originally developed as a residence and bird sanctuary by Wall Street mogul, Wallace Groves, in the 1930s. It has become a lush paradise for numerous birds, including the endangered West Indian Whistling Duck and the Bahama Woodstar, which can be traced back to Groves' original collection.