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Climbing perch threaten Australian waterways
Climbing perch.

The ABC reports that a climbing perch (Anabas testudineus) that can survive several days out of the water, travel across dry land and choke birds and other fish could enter Australia from Papua New Guinea. It has already established itself on Queensland’s Boigu and Saibai islands in the Torres Strait. The climbing perch is a freshwater fish but can survive in briny water.  Scientists and the Queensland Department of Agriculture and Fisheries are currently concerned that the climbing perch could soon be making its way onto the Australian mainland.

The climbing perch, Anabas testudineus, is a freshwater fish native to Southeast Asia. Yet over roughly the past four decades, it has spread through to Indonesia and into Papua New Guinea. It has already been found in two islands in Australian territory of the Torres Strait. The first observations of this, occurred a decade ago back in 2005.  Dr Nathan Waltham, a scientist from James Cook University, is concerned that if the climbing perch is not managed in the Torres Strait, it’s likely the noxious fish could continue its journey southwards to Australia.    Previously the fish have only been found on  Boigu and Saibai islands, and these are the islands that are closest to Papua New Guinea.

What is remarkable about the climbing perch, is its ability to survive. It’s a freshwater fish, but can survive in salty water. As a labyrinth fish, it has the capacity breathe air provided its labyrinth organ is kept moist. Allowing it to survive for prolonged periods, potentially up to weeks, on land. It may also bury into the mud to hibernate, reportedly being able to survive up to six months in this manner.

It’s an aggressive and opportunistic predator. Plus its defence mechanisms include flaring its gill covers. Which typically results in the fatal choking of other fish and birds that try to eat the climbing perch, getting them stuck in their throats. In addition to all that, the climbing perch can ‘walk’ across the land and even climb trees.

This is what the climbing perch looks like:

The director of TropWater at James Cook University, Damien Burrows, said the climbing perch could survive a trip from the Torres Strait on the bottom of a fishing boat. The research team is trying to educate Torres Strait fishermen to throw the fish away before traveling to Australia.  But the Queensland government apparently does not hold out much hope of stopping them. “There is no viable means of eradicating the fish from these islands and an awareness campaign was conducted with island communities to help prevent any further dispersal of these exotic fish,” a spokeswoman said.

Further reading:

Are climbing perch a major incursion threat for Australia?

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