This video from the USA is called Snorkeling & Kayaking with the Manatees of Three Sisters Springs, Florida on February 17, 2013.
From daily The Independent in Britain:
Manatees descend on Florida springs in record numbers
A rush in tides prompted a dramatic surge in numbers
Tuesday 03 February 2015
Officials said the springs reopened to the public on 3 February but would be closed again as manatees returned to the interior of the springs with the rising tide.