[1] The name comes from the island of Anhatomirim, on which a fortress was built by the Portuguese in 1735, later used as a political prison in the time of Floriano Peixoto.

Specific goals include protecting the feeding and reproduction area of the resident population of Tucuxi (Sotalia fluviatilis) freshwater dolphins, and protecting remnants of the Atlantic Rain Forest and water sources needed for survival of local fishing communities.

Migratory species include southern right whale (Eubalaena australis), common bottlenose dolphin (Tursiops truncatus), La Plata dolphin (Pontoporia blainvillei), swallow-tailed kite (Elanoides forficatus), South American tern (Sterna hirundinacea) and rufous-thighed kite (Harpagus diodon).

[1] Protected species include loggerhead sea turtle (Caretta caretta), green sea turtle (Chelonia mydas), La Plata dolphin and restinga tyrannulet (Phylloscartes kronei).

[1] The numbers of tourists visiting the waters by boat for dolphin watching has disturbed these animals, and some researchers have suggested limits if not an outright ban on this activity.