Historical clue formulations

• Manatee — 2023-04-16
• Manatee — 2023-01-15
• [Answer found elsewhere] — 2018-01-04
• Underwater behemoth — 2016-05-12
• Creature with a paddlelike tail — 2010-08-20
• Docile marine mammal — 2010-01-08
• Large marine herbivore — 2004-07-29
• Gentle underwater creature — 2004-02-13
• Placid Everglades denizen — 2003-09-25
• Endangered animal in Florida — 1998-08-24
• Endangered swimmer — 1996-01-21
• Sirenian — 1995-09-16
• Manatee — 1994-03-18