Tuesday, May 18

Rowley Shoals: Australia’s Thriving Reef Shows What’s Possible When Humans Don’t Touch Ecosystems | Coral

What would a tropical reef look like if it could escape the man-made dangers of global warming and overfishing?

A new study suggests it would resemble Rowley Shoals, an isolated archipelago of reefs 260 kilometers off the northwest coast of Australia.

“As soon as you dive in, you realize there is something special,” said fish biologist Matthew Birt. “The coral cover is amazing.”

Birt just led a study on the three reefs that make up the uninhabited Rowley Shoals, using bait cameras that allowed Birt and his colleagues to analyze marine life for 14 years.

The study found that the relative isolation of Rowley Shoals, the protection of commercial fisheries, and its shape and location have sustained threatened species and rich biodiversity during a time of “unprecedented coral reef degradation” in other parts of the world. .

Giant fish like maori napoleon and hunchback parrotfish -Both grow to over 1.5m- were seen regularly at Rowley Shoals, despite their globally threatened status.

“What was remarkable was that there was no real change in abundance [of fish] through time. We don’t see any evidence of decline, ”said Birt of the Australian Institute of Marine Sciences (Aims).

Wrasse (Cheilinus undulatus) in the Rowley Shoals archipelago off Western Australia.
Wrasse (Cheilinus undulatus) in the Rowley Shoals archipelago off Western Australia. Photography: Nick Thake

The three atolls of Rowley Shoals, Imperieuse, Clerke and Mermaid, are about 30 km apart. 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 Western Australian state government, which has also imposed fishing restrictions on the entire reef area.

Coral reefs at Rowley Shoals
Cameras deployed at Rowley Shoals capture reef changes over time. Photography: Matt Birt BRUV

In the three atolls, some 752 square kilometers are classified as “no fishing” where fishing is not allowed. The location, off the coast of Australia and even further from Indonesia, also gave the area protection.

Birt and his colleagues deployed camera arrays 88 times across the three atolls and compared their results with previous observations at the atolls dating back to 2004.

The researchers also compared fish types and numbers to other locations in the same region but further north: Scott Reef, Browse Island, Ashmore Reef, Cocos Islands and Christmas Island, where protections against fishing have not been as strong.

The diversity of fish at Rowley Shoals stood out, making it one of the last coral reef systems in the Indian Ocean free from human disturbance, according to the journal study. Ecology and Evolution saying.

“In the right conditions, this is what a reef can look like,” Birt said.

Despite the fact that Rowley Shoals had been hit by cyclones in years past, the corals had escaped the damaging bleaching that had affected reefs further north in previous years.

The tiger shark (Galeocerdo cuvier), in the Rowley Shoals archipelago off Western Australia.
The tiger shark (Galeocerdo cuvier), in the Rowley Shoals archipelago off Western Australia. Photography: Matt Birt BRUV

Aims coral ecologist Dr James Gilmour said Rowley Shoals was now one of the healthiest reef systems in Australia.

The large number and variety of fish made the coral ecosystem more resilient, he said.

Last year, a global study found that unsustainable fishing on tropical reefs around the world had caused a drop in the number of sharks, a species that marine scientists say is vital to the health of ecosystems.


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