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Has Australia found a solution to our Carp problems?


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#21 Guest_FishheadDave_*

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Posted 15 November 2010 - 09:01 AM

I don't think it would work as well here. Gar, among others, are good jumpers that are likely to be taken with carp. I've caught several gar in turtle traps with no submersed entrance. Still, it's interesting stuff.


Just for sake of argument - would it be worth killing huge numbers of gar as bycatch if we could substantially reduce asian carp populations? For that matter, would it be worth sacrificing a few RTE fish species to maintain or restore the basic ecology and function of the ecosystem?


This strategy could also be highly effective and practical in the Great Lakes, where asian carp are not yet well established.

#22 Guest_Newt_*

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Posted 15 November 2010 - 11:03 AM

We would need far more information and better models of the consequences of such actions before we could make any judgements on whether they are "worth" the sacrifice. I think the Hippocratic injunction to first do no harm is as important in conservation as it is in medicine.

#23 Guest_Newt_*

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Posted 15 November 2010 - 11:21 AM

I'm also very dubious of the ability of any sort of removal effort to make a serious impact on adaptable and fecund species such as carp.

Look at the long and only partially successful efforts to remove feral hogs and goats from various islands and parks. These are limited populations of large animals with low reproductive rates in isolated areas- about the best conditions you could hope for in terms of ease of removal- and these animals still often defy eradication efforts.

Now consider carp: enormous populations of animals with incredible reproductive potential widespread in vast interconnected drainage systems. Trying to eradicate carp from the American landscape would be like trying to eradicate dandelions, Norway rats, starlings, Chinese cockroaches, or any of the other high-r-strategy exotic "weeds". Not to say that there isn't a way, but trapping carp is like pulling up dandelions. Other methods must be sought.

There are certainly instances of successful elimination or near-elimination of once absurdly populous species. Passenger pigeons, bison, and cod are three familiar North American examples. We did it by destroying crucial habitat- feeding grounds, nesting areas, migration corridors- or by interrupting the food chain. The wholesale slaughter usually blamed for their declines is a secondary issue- salt in the wound.

However, these were species of established communities; carp, like other weed species, specialize in taking advantage of disturbed communities. Attempting to restore these areas to something like an undisturbed state might help, but unfortunately carp are very good at maintaining their habitat in a disturbed state. They uproot stabilizing vegetation and keep water turbid with their benthic foraging.

#24 Guest_FishheadDave_*

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Posted 15 November 2010 - 06:47 PM

I'm also very dubious of the ability of any sort of removal effort to make a serious impact on adaptable and fecund species such as carp.

Look at the long and only partially successful efforts to remove feral hogs and goats from various islands and parks. These are limited populations of large animals with low reproductive rates in isolated areas- about the best conditions you could hope for in terms of ease of removal- and these animals still often defy eradication efforts.

Now consider carp: enormous populations of animals with incredible reproductive potential widespread in vast interconnected drainage systems. Trying to eradicate carp from the American landscape would be like trying to eradicate dandelions, Norway rats, starlings, Chinese cockroaches, or any of the other high-r-strategy exotic "weeds". Not to say that there isn't a way, but trapping carp is like pulling up dandelions. Other methods must be sought.

There are certainly instances of successful elimination or near-elimination of once absurdly populous species. Passenger pigeons, bison, and cod are three familiar North American examples. We did it by destroying crucial habitat- feeding grounds, nesting areas, migration corridors- or by interrupting the food chain. The wholesale slaughter usually blamed for their declines is a secondary issue- salt in the wound.

However, these were species of established communities; carp, like other weed species, specialize in taking advantage of disturbed communities. Attempting to restore these areas to something like an undisturbed state might help, but unfortunately carp are very good at maintaining their habitat in a disturbed state. They uproot stabilizing vegetation and keep water turbid with their benthic foraging.



I mostly agree with you, and was just throwing that tradeoff out there for discussion.

In MD, nutria (a highly fecund, in mammalian terms, rodent) were abundant and widespread in Blackwater National Wildlife Refuge, and yet managers were able to implement a successful eradication program. How? Turns out they aggregate in the winter months to stay warms, and could be killed by the dozens. Although the Mississippi drainage seems impossible huge, this story offers a glimmer of hope.

#25 Guest_Newt_*

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Posted 15 November 2010 - 08:53 PM

Other pest species that are being successfully controlled (sea lampreys in the Great Lakes, screwworms and boll weevils in the southern US and Mesoamerica) have some weakness in their biology- breeding runs into streams for lampreys, population concentration in cotton fields and extra susceptibility to pesticides at the onset of diapause for the boll weevil, single-copulation mating strategy in screwworms- that makes them vulnerable to eradication efforts, just as in your nutria example.

Do carp have such a weakness? They do move into newly flooded areas in spring to breed over the submerged terrestrial vegetation, but these are still pretty spread out. There's no real funnel effect to make catching them easier. I hope further research will reveal such a weakness. I also hope that at some point carp elimination will attract funding. They do not cause the obvious damage that the previously listed species do. A dollar amount makes cost-benefit analysis much easier.

#26 Guest_smilingfrog_*

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Posted 16 November 2010 - 01:52 PM

Do carp have such a weakness? They do move into newly flooded areas in spring to breed over the submerged terrestrial vegetation, but these are still pretty spread out. There's no real funnel effect to make catching them easier. I hope further research will reveal such a weakness. I also hope that at some point carp elimination will attract funding. They do not cause the obvious damage that the previously listed species do. A dollar amount makes cost-benefit analysis much easier.


Here's something they were trying in Minnesota.
http://www.startribu...Yyc:aUycaEacyUs
It certainly won't work in all applications, but apparently there is a weakness that can be exploited in some situations.

#27 Guest_wargreen_*

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Posted 19 November 2010 - 09:07 AM

Here's something they were trying in Minnesota.
http://www.startribu...Yyc:aUycaEacyUs
It certainly won't work in all applications, but apparently there is a weakness that can be exploited in some situations.






Excellent article....thank you, I am always encouraged by people looking for solutions; I believe there is one it just may not be easy to find.




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