SYDNEY -- The world's pristine marine areas are rapidly disappearing amid the growing impact of human activity, with just 13 percent of the ocean that can still be classified as wilderness, according to latest Australian-led research.

"Marine areas that can be considered pristine are becoming increasingly rare as fishing and shipping fleets expand their reach across almost all of the world's oceans, and sediment runoff smothers many coastal areas," University of Queensland researcher Kendall Jones said on Friday.

"Improvements in shipping technology mean that even the most remote wilderness areas may come under threat in the future, including once ice-covered places that are now accessible because of climate change."

The international study, led by the university's scientists, identified marine areas devoid of intense human impacts by analyzing 19 "stressor" agents including commercial shipping, sediment runoff and several types of fishing.

The researchers found little wilderness remaining in coastal habitats such as coral reefs because of the nearby human activities. Most marine wilderness was located in the Arctic and Antarctic or around remote Pacific island nations such as French Polynesia.

The findings, which were published in scientific journal Current Biology, highlight "an immediate need for conservation policies to recognize and protect the unique values of marine wilderness," said the university's Professor James Watson, who is also director of science at the Wildlife Conservation Society.

"Marine wilderness areas are home to unparalleled levels of life, holding massive abundances of species and high genetic diversity, giving them resilience to threats like climate change," said Watson.

"We know these areas are declining catastrophically, and protecting them must become a focus of multilateral environmental agreements," he added.