The world's first continent-wide survey of reef sea life has found big fish gone around much of the Australian coastline.

A year-long circumnavigation of Australia ended in Hobart on Wednesday with a trove of data from 700 coral and rock reef sites surveyed by volunteer divers for the Reef Life Survey Foundation.

Exhaustive: Jemima Stuart-Smith collects data for the first continent-wide survey of reef sea life which ended in Hobart. Credit:Rick Stuart-Smith

Program co-founder Graham Edgar, of the University of Tasmania, said the first comprehensive study of any continent's reef systems found biodiversity losses, compared to earlier local counts.

''Virtually all of our coastline has had all the larger predatory organisms reduced - from the big fishes to the lobsters,'' said Professor Edgar, from the UTAS Institute of Marine and Antarctic Studies.