Research into rare bum-breathing turtles
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Brian Williams
September 10, 2008
SCIENTISTS are trying to figure out why some turtles benefit from breathing through their bottoms and are investigating their diet and lifestyle.
The so-called bum breathers can breathe by absorbing air from water taken in through their cloaca.
James Cook University physiologist Suzy Munns and ecologist Ivan Lawler are investigating the turtles, in particular the Irwin’s turtle.
It was found by Bob Irwin and later named after his late Crocodile Hunter son Steve. It is known only in north Queensland’s Broken-Bowen River and the lower Burdekin.
With about 5000 left in the wild and proposals for the Urannah dam to be built on the river, the turtles’ future is bleak.
“We believe that one of the major benefits of cloacal breathing is the amount of energy spent on having to surface is reduced significantly simply because they can obtain their oxygen from the surrounding water and so don’t have to surface to breathe,” Dr Munns said.
“We have not yet established how widespread cloacal breathing is and what advantage it confers, if any.”
During digestion a turtle’s resting metabolic rate may increase by up to three to five times the resting level.
“This increase may consume up to 30 per cent of the energetic value of the meal,” Dr Lawler said.
“Couple that with the fact that many have to then haul their body weight to the surface to breathe and it’s a significant cost.”
Another mystery is why different species choose to live at different points in the river and rarely cohabit.
One theory is that because Irwin’s turtle does not need to use energy to surface, it can live in areas where food is scarce. The turtle does not have to compete with neighbouring species.
Last year University of Queensland scientist Natalie Mathie found the endangered Mary River turtle, also a bum breather, could stay submerged for at least three days, possibly up to a week.
This allowed the turtle to avoid predators such as birds and hide from fish or eels.
Update on Wednesday, September 10, 2008 at 07:57AM by
stevem
stevem
Rare fish not threatened by Traveston dam, says report
Brian Williams
September 10, 2008
THE planned Traveston Dam will not put any rare lungfish, cod and turtles in danger, according to a report into the controversial development.
The Queensland Water Infrastructure paper - which summarises the project’s Environmental Impact Statement and supplementary EIS - addresses environmental concerns raised by the public and scientists about the dam’s impacts on the Mary River.
It says the lungfish, arguably the world’s most scientifically significant fish, is not the rarest fish in the Mary River and is well represented in the Burnett and Brisbane rivers.
The dam will provide suitable habitat and conditions for breeding, the report says.
Written by QWI environment manager Lee Benson, the report says the Mary River cod also is expected to breed despite the dam.
And it says the Mary River turtle, which does not rely on running water for breeding, should prosper.
Dr Benson says 78 per cent of the dam’s catchment is below the dam wall and 90 per cent of mean average flows will still make it to the rivermouth.
Protesters hoping to quash plans for the dam have pinned their hopes on it being rejected by Federal Environment Minister Peter Garrett, who will make his decision in coming months.
Mary River Action Group spokesman Kevin Ingersole said the paper was pathetic.
“This is just spin,” he said. “It’s plausible stuff until you dig into the details.
“We are outraged the community spent hundreds of thousands in preparing comments on the EIS and then they won’t show us the supplementary although they’ve sent it to all departments.”
Macquarie University lungfish expert Jean Joss said the dam should not be approved.
“It’s not going to be fine for lungfish,” she said.
“Eighty per cent of prime spawning sites went when they built the Paradise Dam (on the Burnett River).”
Professor Joss said dam managers would not release water in dry seasons. “They want water for people, not fishes,” she said. “That’s why they are spending $2 billion on it.
“This dam is absolute stupidity and I don’t care if they knock me off their advisory committee for saying so.”
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Reader Comments (2)
Where is this paper????
Here's the link to the new paper
http://www.springerlink.com/content/003p3904l8n3l26t/fulltext.pdf
and here's the abstract:
Quote:
Australian lungfish, Neoceratodus forsteri , threatened by a new dam
Angela H. Arthington
Australian Rivers Institute and eWater Co-operative Research Centre, Griffith University, Nathan, Queensland, 4111, Australia
Received: 11 February 2008 Accepted: 13 August 2008 Published online: 5 September 2008
Abstract The Australian lungfish, Neoceratodus forsteri, exists as remnant natural populations in two rivers of south-east Queensland, Australia, and several translocated populations. Lungfish habitats have been impacted by agriculture and forestry, alien plants and fish and by river impoundment and regulation of flows. The species has been listed as vulnerable under Australian Commonwealth legislation. A proposal to construct Traveston Crossing Dam on the free-flowing main channel of the upper Mary River could seriously threaten the lungfish. The dam can be stopped by Commonwealth legislation if important populations of lungfish in the Mary River are likely to be significantly impacted by the new dam. This paper assembles evidence that impoundment of the Mary River and regulation of river flows are likely to decrease and fragment important lungfish populations, disrupt the breeding cycle, reduce juvenile recruitment, and isolate and decrease habitat availability/quality to such an extent that the species is likely to decline. Proposed mitigation strategies include fish transfer facilities, provision of flow releases from the dam (environmental flows) to sustain lungfish habitat and breeding downstream, and translocation of hatchery-reared juvenile lungfish into suitable natural habitats. These mitigation efforts may not be sufficient to secure the genetic diversity and long-term viability of lungfish populations in the Mary River.