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Explosion of feral carp after flooding


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Explosion of feral carp after flooding

October 7, 2012

Nicky Phillips

THE number of feral carp in some NSW rivers has exploded by up to 4000 per cent in the past two years, say fisheries experts, who are expecting a further incursion of the pest as juveniles reach sexual maturity in the next year.

Drought-breaking rains in 2010 filled the state's parched rivers, and the subsequent floods led to an outbreak of the invasive fish species, known as the rabbit of the waterways.

The chief executive of the Invasive Animals Co-operative Research Centre, Andreas Glanznig, said the carp competed with native fish for food and habitat.

''After the last major floods the number of new carp in the system increased by up to 4000 per cent,'' Mr Glanznig said.

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According to the NSW Department of Primary Industries, carp were widespread through most of NSW, particularly in the Murray-Darling Basin and the rivers of the mid-north coast, and the central and southern tablelands.

In some places in the Murray-Darling carp make up 80 per cent of the fish biomass, Mr Glanznig said.

Females reach sexual maturity at three to five years of age and produce 1 illion eggs, on average, when they spawn each year. Males can procreate from two years of age, which means those fish born after the drought will be ready to reproduce this spring.

As bottom feeders carp increase water turbidity, which means less light reaches water vegetation, and they also consume the eggs of other fish and invertebrates.

European carp have been present in the state's waterways for more than a century. To manage the pest, the Department of Primary Industries place cages that collect carp while allowing native fish through to waterways.

Unlike in Europe and Asia, there is limited demand for carp as a food source in Australia.

Scientists at the CSIRO's Australian animal health laboratory in Geelong are testing a biological control for the pest.

A research veterinarian, Ken McColl, said their experiments had shown the carp herpes virus was highly specific to carp and did not affect native fish or other animals.

The team hope to have the virus ready for approval within three years.

The varieties of freshwater fish introduced into Australian river systems have increased from 22 to 34 in the past 20 years.

Read more: http://www.smh.com.au/environment/animals/explosion-of-feral-carp-after-flooding-20121006-2761l.html#ixzz28Z2dQq5R

Edited by MallacootaPete
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These noxious fish are choking some of the skinny waterways here in Vic as well. Some of the channels contain huge numbers of carp in XOS sizes. It will be interesting to follow the progress of this study. Interesting article Pete! :thumbup:

Cheers

Hodgey

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A bit more reading on the technical side for those interested.

It seems this virus can knock them over in about a week and

eradication levels can reach 100%, given the right water temps.

I just hope they do their homework thoroughly, as Australia's history is littered

with failed biological control attempts and our waterways are too important to

get it wrong.

http://www.feral.org.au/wp-content/uploads/2012/04/CPFS7.pdf

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A bit more reading on the technical side for those interested.

It seems this virus can knock them over in about a week and

eradication levels can reach 100%, given the right water temps.

I just hope they do their homework thoroughly, as Australia's history is littered

with failed biological control attempts and our waterways are too important to

get it wrong.

http://www.feral.org.au/wp-content/uploads/2012/04/CPFS7.pdf

I think it is a great strategy with potential for great results. If they are correct and the virus cannot jump to native species then go ahead. The only disadvantage of using a virus is the fish will adapt and eventually become immune, just like rabbits and the myxoma virus. Maybe the use of a virus and other strategies to fully purge systems before the carp population becomes resistant.

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Chewy, a 4000% increase is 40 Carp to maturity for each breeder :)

Still its a scary number if you think that in 3 years, those 40 carp will breed another 1600, and within 3 years after that 65,600.

100 carp now = 6,560,000 in 6 years....

It's probably capped based on food and environmental factors, but it's easy to see how they choke a waterway.

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maybe we should have a carp bash i used to fish one at lake ladell up the hunter it was a week end comp you can camp by the lake and it was a fun weekend there are also monster eels there so big they would restrict water flow into the power station cheers gary

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Carp are good fun to catch and fight better than most native fish. Pity they're not good on the plate or they would be an asset.. However ,they are a major problem in our waterways and I hope the scientists can help to reduce their numbers, which are at epidemic proportions. Neil.

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  • 8 months later...

Carp cost more to buy in the shops than Australian Salmon and I actually see people buying them. If anyone can suggest where I can get these on my line around Parramatta that would be great. Ive tried parramatta lake but its near impossible to burly for them without 2000 ducks coming and stealing the bread. I saw a few guys fishing down near the bats meeting point in parra park. They looked setup with heavy gear I did laugh quite alot but I assume there is carp there. Not to keen to fish near those bats incase they carry bat lyssavirus.

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Sarge RX8,it's easy to berley for Carp by sinking the bread to the bottom where the Carp will congregate. Saturate several slices of bread then wring out most of the water, whilst squeezing the bread into a firm ball. As long as it's got no air in it , it will sink to the bottom and the Carp will come from everywhere. Best distributed in small ( 1cm dia.) balls over an easily accessible area. Cheers, Big Neil.

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I'll try that next time I go out for them. I'm gonna try corn for bait. A mate suggested I'll have a better chance on corn than I would on bread. Are there any scents which attract them? Would SFactor on a corn kernel give any benefit?

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