Exmouth gulf home to secret whale nursery

Two whales

A study led by The University of Western Australia and Oceanwise Australia has revealed the remarkable biodiversity of the Exmouth Gulf in Western Australia’s remote North West, including a secret nursery where whales whisper to their calves.

Led by Dr Ben Fitzpatrick, an adjunct research fellow from UWA’s Oceans Institute and director of Oceanwise Australia, the studyfound that Exmouth Gulf estuary was home to more than 1800 fauna species.

The researchers found 790 species of fish, 63 species of sharks and rays, 173 species of crustaceans, 831 species of molluscs and 95 species of birds.

Located next to the World Heritage-listed Ningaloo Reef, Exmouth Gulf is also a global sea snake hotspot. The researchers were surprised to discover more than 15 species of sea snakes – including two species previously thought to be extinct.

The gulf is an important nursery for a range of vulnerable species and a globally significant pupping site for the endangered green sawfish. The gulf also supports endangered juvenile hawksbill turtles and is one of the world’s most significant whale nurseries and plays an essential part in one of the greatest conservation successes – the recovery of humpback whale populations.

Dr Fitzpatrick said Exmouth was a relatively pristine wilderness area that had not been industrialised.

“It is a quiet place where the whales need only whisper to their calves, enabling them to feed, rest, elude detection by predators and raise them successfully,” he said.

“Keeping Exmouth Gulf quiet will be the key to the ongoing success of our humpback whales and the sustainable ecotourism industries worth millions of dollars annually to local communities.”

The 2600sqkm estuary has large, unmodified mangrove forests, inter-tidal habitats, fossil coral reefs and subterranean waterways of global conservation significance.

“Exmouth Gulf is even richer and more significant than we anticipated. In terms of bony fish alone, it has nearly twice as many species as Ningaloo Reef, which is a World Heritage Area,” Dr Fitzpatrick said.

“Surprisingly, given the value of this ecosystem to conservation, fisheries and ecotourism, very little is understood of the importance of the diverse range of habitats in the Exmouth Gulf and their role in sustaining the populations of species that occur there.”

The report notes Exmouth Gulf is vulnerable to climate change and other human impacts, including industrial development. Dr Fitzpatrick said during the past 40 years many state and federal agencies and international bodies had recommended the Gulf should be protected for its biodiversity value.

“Our study has highlighted that the biodiversity, social and economic value of this area is far greater than previously known and that the Gulf is a very significant ecosystem that deserves study and protection.”

A collaboration of UWA’s Oceans Institute, Oceanwise Australia, James Cook University and Curtin University, the research is endorsed by the International Union for the Conservation of Nature.

Oceanwise Australia is a specialised environmental sciences firm contributing research, management, conservation and monitoring of marine and coastal ecosystems. Dr Fitzpatrick established Oceanwise in 1998 to promote awareness of the marine environment of the Ningaloo Reef.

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