Threatened fish thrive in Rowley Shoals, WA, a coral safe haven that’s free from overfishing and other human interference

By Australian Geographic April 8, 2021
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Rowley Shoals, a marine reserve in the Indian Ocean, provides a stark but important contrast to areas suffering from overfishing.

About 260km west of Broome, Western Australia, in the Indian Ocean, Rowley Shoals – a group of coral atolls – boasts greater fish diversity than areas currently facing overfishing and is providing a safe haven for globally threatened fish, including the humphead Maori wrasse and bumphead parrotfish. 

A long-term study of Rowley Shoals conducted by the Australian Institute of Marine Science (AIMS) found that fish diversity has remained “remarkably stable”, which the authors attribute to the marine protections it was given two decades ago. 

The scientists harnessed 14 years of data from baited remote underwater video stations (BRUVS) from Rowley Shoals and compared it to fish diversity on remote reefs still facing fishing pressure in northern WA.

AIMS lead author and fish biologist Matthew Birt says the study demonstrates the importance of marine reserves that protect the ocean from human interference. 

“Rowley Shoals is one of the last coral reef ecosystems left in the Indian Ocean largely spared from human interference,” Matthew says.

“There’s no human population nearby, low visitation rates and, importantly, has large no-take areas that have been enforced for decades.”

Related: Underwater and underrated: the truth behind fish intelligence

Matthew was particularly thrilled to see a strong population of humphead Maori wrasse and bumphead parrotfish, which are being pushed to the brink in other areas.

“These species are highly sensitive to fishing pressure because they are large, slow growing and late maturing,” he says.

“Comparably, Ashmore Reef and Christmas Island had no recorded humphead Maori wrasse or bumphead parrotfish – likely a result of historical fishing pressure and a lack of suitable habitat.

“Rowley Shoals is an example of a well-managed marine reserve, with diverse habitat types and low historical fish pressure, making it a unique baseline to compare with other isolated reefs under human pressure.”

Related: Parrotfish: the coral crunching, sand makers

Co-author of the new research and coral ecologist James Gilmour says Rowley Shoals is a unique haven for fish. 

“It’s one of the only places in Western Australia with consistently high coral cover and diversity for more than 20 years,” he says.

“It is far from the coastline which means it has excellent water quality and is largely free of wide-scale bleaching events.

“Having diverse and abundant fish on coral reefs also supports the resilience of coral reef Communities.”