Dugong calf numbers, wiped out on the Great Barrier Reef six years ago, have recovered and are thriving, new research has found.

An aerial survey conducted late last year has shown a significant recovery of the large sea mammal's population since Cyclone Yasi and widespread flooding damaged their seagrass food supply in 2011.

The number of dugong calves on the Great Barrier Reef have increased, researchers have found. Credit:Sarah Thomas

Numbers in the southern region of the reef have increased to more than 10 per cent of the current population, according to the James Cook University survey.

Scientists estimated there were some 5500 dugongs in the waters between Hinchinbrook Island and the Queensland-New South Wales border at the time of the survey, with just over half found in the reef's world heritage area.