Olifants River ecosystem change & croc mass mortality

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Toko
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Olifants River ecosystem change & croc mass mortality

Post by Toko »

Ecosystem change and the Olifants River crocodile mass mortality events. Ecosphere
3(10):87. 2012

Nile crocodile (Crocodilus niloticus) mass mortality events in the Olifants River between the Letaba River confluence in South Africa and Lake Massingir in Mozambique have been attributed to pansteatitis: a disease that affects fat depots of the animals. The disease is also found in sharptooth catfish (Clarias gariepinus) in the same area, and the cause of the disease is attributed to pollution. Although the Olifants River Valley is polluted, the impact of interventions such as dam construction on biodiversity receives little attention. We show that the onset of the pansteatitis epidemic in crocodiles and sharptooth catfish at the Olifants/Letaba confluence coincided with back-flooding of Lake Massingir that changed the Olifants River from a rock and sand substrate river to a clay substrate lake. Isotopic analysis shows that sharptooth catfish shifted from a predominantly vegetarian to a piscivorous diet that is highly correlated with pansteatitis prevalence, and crocodiles and tiger fish (Hydrocynus vittatus) show coincident trophic level increases. The evidence suggests that the ecosystem change altered the structure of the lotic foodweb and that an exotic or extralimital fish has invaded the confluence and is the vector of the pansteatitis
epidemic. The invasive fish species is yet to be identified. The pansteatitis epidemic is an unintended ecological consequence of damming this river.


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Re: Olifants River ecosystem change & croc mass mortality

Post by dup »

Thanks Toko,I have a big interest in this story and like to hear every bit of info.


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Re: Olifants River ecosystem change & croc mass mortality

Post by Richprins »

Ja!

Just to clarify, the Massingir Dam wall was raised...leading to the Dam backing up into the Park.


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Re: Olifants River ecosystem change & croc mass mortality

Post by dup »

The interesting thing will be the invading fish specie ,the Silver carp(not Grass carp) was introduce as food source in some rivers in Moz. We saw Silver carp of 6-8 kg been caught at Komatipoort by local line fishermen. :-?


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Re: Olifants River ecosystem change & croc mass mortality

Post by Richprins »

This is still pretty experimental re. an inveder species, I think. Remember the huge croc die-off in the Olifants a few years back? That was before the dam was raised, an along much of the length of the river in Kruger... :-?


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Pollution of Selati river

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Pollution affects the Olifants River in Kruger National Park
Back to all newsDate: 6th January 2014


The South African National Parks (SANParks) today announced that there has been spillage of polluted water from a tailings dam at Bosveld Phosphate, a mining operation, into the Selati River near Phalaborwa. The incident was detected by Kruger National Park (KNP) staff, after a tip off by a local fisherman on 30 December 2013, who had witnessed a massive fish kill.


Heavy rains in Phalaborwa over the weekend of 28 to 29 December 2013 contributed to the overflow of the tailings dam. This resulted in highly acidic water being discharged directly into the Selati River just upstream of its confluence with the Olifants River. The Selati River is an important tributary of the Olifants River, arguably the most environmentally stressed major river system in South Africa and an important shared watercourse with Mozambique.

Investigations into the environmental impact of the spillage are continuing and will be made public once they have been concluded. There is also continuous monitoring of the rivers affected to assess their condition.

SANParks took immediate precautions to ensure safe water supply to tourist camps in the park. Currently those camps dependent on water from the Olifants River have been switched onto back-up borehole water, with associated water use restrictions to ensure that the water demand can be met. Water quality is thus unaffected in KNP tourist camps.

The Department of Water Affairs and South African National Parks are cooperating closely on investigations into this incident and are conducting in-depth investigations into the associated environmental impacts. Intensive monitoring of the environmental conditions are on-going to evaluate the scale of the degradation.

Issued by:
South African National Parks (SANParks) Kruger National Parks Communications Tel: 013 735 4300/ Cell: 082 908 4328 / Email: lerato.mathole@sanparks.org

Enquiries:
Nigel Adams, Director: Compliance Monitoring and Enforcement, Department of Water Affairs. Cell: 082 806 5306.

Ike Phaahla, Media Specialist, SANParks. Cell: 083 673 6974; or email: isaac.phaahla@sanparks.org.

Dr Eddie Riddell, Manager: Water Resources, Kruger National Park, SANParks. Cell: 072 337 1274.

Dr Stefanie Freitag-Ronaldson, General Manager: Savanna Research Unit, Scientific Services, SANParks. Cell: 082 908 2678.


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Re: Pollution of Selati river

Post by nan »

oups 0*\


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Re: Pollution of Selati river

Post by Sprocky »

Big oops!! :shock: Bosveld are in a financial crisis already, something like this could shut them down. 0-


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Re: Pollution of Selati river

Post by H. erectus »

Sprocky wrote:in a financial crisis already, something like this could shut them down.
Just hope they clean the mess and take responsibillity before
shutting door!! This is where ethical standards are last to be
noticed!!!!


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Re: Pollution of Selati river

Post by Richprins »

We had a similar thing down here on the Kaap river...the mining company methodically checked everything and gave their side of the story, and it wasn't so bad... 0()


But anyway, another reason not to blow up dams and artificial water points just yet, IMO! ;-)


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