What would a tropical reef look like if it escaped the dangers of global warming and overfishing?
A new study suggests that it will look like Rowley Shoals, an isolated coral reef archipelago 260 km off the northwest coast of Australia.
“Once you dive in, you realize that there is something special,” says fish biologist Matthew Birt. “Incredible coral cover.”
Birt recently led research on the three coral reefs that make up the uninhabited Rowley Shoals, using a bait camera that allowed Birt and his colleagues to analyze marine life over 14 years.
The study found the relative isolation of Rowley Shoals, protection from commercial fishing, and their shape and location have sustained threatened species and rich biodiversity during a time of “unprecedented coral reef degradation” elsewhere around the world.
“What’s amazing is that there is no real change in abundance [of fish] passing time. We don’t see any evidence of decline, ”said Birt, of the Australian Institute of Marine Sciences (Aims).
The three Rowley Shoals atolls – Imperieuse, Clerke and Mermaid – are about 30 km away. Mermaid Reef is a marine park managed by the Australian government where fishing is not allowed.
The Imperieuse and Clerke reefs are managed by the state government of Western Australia which also imposes a fishing ban on all reef areas.
Across the three atolls, some 752 sq km are classified as “no-take” where fishing is not allowed. Its location – further off the coast of Australia and even further from Indonesia – also provides regional protection.
Birt and colleagues mounted camera sets 88 times on three atolls and compared their results with previous observations on atolls in 2004.
The researchers also compared fish species and numbers with other locations in the same area but further north – Scott Reef, Browse Island, Ashmore Reef, Cocos Islands and Christmas Island – where protection from fishing has not been that strong.
The diversity of fish in the Rowley Shoals stands out, making it one of the last coral reef systems in the Indian Ocean free from human disturbance, studies in the journal. Ecology and Evolution the word.
“Under the right conditions, this is what coral reefs look like,” said Birt.
Although the Rowley Shoals have been hit by typhoons in the past years, the reef has escaped the devastating bleaching that has hit reefs further north in previous years.
Coral ecologist Dr James Gilmour said Rowley Shoals are now one of the healthiest reef systems in Australia.
The high number and types of fish make the coral ecosystem more resilient, he said.
Last year, a Global studies find fishing is unsustainable on tropical reefs around the world have led to a drop in shark numbers – a species marine scientists think is essential for healthy ecosystems.