What is the largest aquatic Herbivore?

The Manatee (dugong, mermaid or sea cow ) is one of four Herbivorous living species of the order Sirenia. They are the only living representatives of the once-diverse family Dugongidae; its closest modern relative,pp Steller's sea cow (Hydrodamalis gigas), was hunted to extinction in the 18th century. Dugongs are long-lived, and the oldest recorded specimen reached age 73.

Manatees are the largest herbivores in the ocean, they. can be up to 4 metres long and weigh up to 1300kg. The dugong is largely dependent on seagrass communities for subsistence and is thus restricted to the coastal habitats. Its snout is sharply downturned, an adaptation for feeding in benthic seagrass communities.