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The game may be over: Asian carp beyond electric barriers

Started by Guest_az9_* , Nov 21 2009 11:41 AM

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#21 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 29 December 2009 - 10:44 PM

Biological control (using one species in an effort to control another species) has been employed successfully for many years.

Not to pick a fight, but please name a few of these successfully employed situations. I am mostly aware of some of the huge failures (rats, snakes, and mongoose in Hawaii comes to mind immediately).

Either write something worth reading or do something worth writing. - Benjamin Franklin

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#22 Guest_DavidPT40_*

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Posted 30 December 2009 - 07:13 AM

This is a list of effective biological controls when dealing with agriculture. I'll add some more examples when I have more time:

Some biocontrol agents that can be introduced include;

* Encarsia formosa. This is a small predatory chalcid wasp which is parasitical on whitefly, a sap-feeding insect which can cause wilting and black sooty moulds. It is most effective when dealing with low level infestations, giving protection over a long period of time. The wasp lays its eggs in young whitefly 'scales', turning them black as the parasite larvae pupates. It should be introduced as soon as possible after the first adult whitefly are seen. Should be used in conjunction with insecticidal soap.

* Red spider mite, another pest found in the greenhouse, can be controlled with the predatory mite Phytoseilus persimilis. This is slightly larger than its prey and has an orange body. It develops from egg to adult twice as fast as the red spider mite and once established quickly overcomes infestation.

* A fairly recent development in the control of slugs is the introduction of 'Nemaslug', a microscopic nematode (Phasmarhabditis hermaphrodita) which will seek out and parasitize slugs, reproducing inside them and killing them. The nematode is applied by watering onto moist soil, and gives protection for up to six weeks in optimum conditions, Nemaslug nematodes are mainly effective with small and young slugs under the soil surface.

* A bacterial biological control which can be introduced in order to control butterfly caterpillars is Bacillus thuringiensis. This available in sachets of dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees. The bacterial disease will kill the caterpillars, but leave other insects unharmed. There are strains of Bt that are effective against other insect larvae. Bt israelensis is effective against mosquito larvae and some midges.

The European Rabbit (Oryctolagus cuniculus) is seen as a major pest in Australia

* A viral biological control which can be introduced in order to control the overpopulation of European rabbit in Australia is the rabbit haemorrhagic disease virus that causes the rabbit haemorrhagic disease.

* A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma viride. This has been used against Dutch Elm disease, and to treat the spread of fungal and bacterial growth on tree wounds. It may also have potential as a means of combating silver leaf disease.

* Several species of dung beetle were introduced to Australia from South Africa and Europe during the Australian Dung Beetle Project (1965-1985) led by Dr. George Bornemissza of the Commonwealth Scientific and Industrial Research Organisation in order to biologically control the population of pestilent bush flies and parasitic worms[8].

* The parasitoid Gonatocerus ashmeadi (Hymenoptera: Mymaridae) has been introduced to control the glassy-winged sharpshooter Homalodisca vitripennis (Hemipterae: Cicadellidae) in French Polynesia and has successfully controlled ~95% of the pest density[9]

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#23 Guest_fundulus_*

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Posted 30 December 2009 - 10:37 AM

But the rabbits in Australia have largely evolved an immunity to the hemorrhagic disease in a classic example of microevolutionary response. The virus has killed as many as 99.9% of the rabbit population, few rabbits are seen for about 10 years, and then they're back. It's the same reason that many formerly effective antibiotics are of little use against tuberculosis. The problem in the Great Lakes is that the original ecosystem has been badly degraded; will successive introductions of exotics "fix" that problem?

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#24 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 30 December 2009 - 10:58 AM

Some of those are quite good. I like the idea of using something natural. And in a controlled space like a greenhouse (or an aquarium) I think they are preferable to chemical methods. So from that standpoint, I would support their use. But in a large scale situation (like australia or hawaii), there are too many factors to control, and too great a risk of unanticipated consequences.

Either write something worth reading or do something worth writing. - Benjamin Franklin

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#25 Guest_smilingfrog_*

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Posted 30 December 2009 - 12:25 PM

Why can't native piscivorious fish populations be increased in response to the carp invasions? I know that nothing in the Great Lakes will eat a full grown carp, but fry, fingerlings, and juveniles are all fair game. Pike, muskie, salmon, and bass are all native to the Great Lakes. Increase these populations, and hypothetically the carp populations will go down too, right?

Increasing predator populations in a localized area around the site of carp introduction could certainly reduce the number of individual carp that make it to adulthood assuming that the predator and the smaller juvenile carp occupy the same type of habitat (ie predator will be able to find and eat small carp). To have the desired effect though, the number of predator fish would have to be sustained in unnaturally high numbers at a size where they could prey upon the carp. In other words it wouldn't work to just start tossing in half a million northern pike fry and hope they grow up and eat the carp as most of them will starve to death or be eaten by larger predaotrs that are already in the area. Sustained stocking of larger pike might work to reduce carp if the previously mentioned assumption holds true. One problem, it would be quite expensive. Since you need the pike to stay in the localized area, stocking needs to be an ongoing effort. The unnaturally high numbers will exhaust the local food supply of the area (the whole point, since part of this food supply is the juvenile carp) and the pike will respond by leaving and or starving to death. I doubt that those leaving the area would have a profound effect on the rest of the lake as they would be competing with pike in other parts of the lake and in essence, either they or another pike would lose out and starve.
Electricity and rotenone are simply cheaper than sustaining large numbers of large pike.
I used pike as an example, but you could obviously interchange any or all of the predator fish you mentioned though salmon aren't actually native to Lake Michigan.

Edited by smilingfrog, 30 December 2009 - 01:01 PM.

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#26 Guest_Irate Mormon_*

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Posted 30 December 2009 - 11:13 PM

There was an old lady who swallowed a fly...

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#27 Guest_keepnatives_*

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Posted 30 December 2009 - 11:43 PM

Why can't native piscivorious fish populations be increased in response to the carp invasions? I know that nothing in the Great Lakes will eat a full grown carp, but fry, fingerlings, and juveniles are all fair game. Pike, muskie, salmon, and bass are all native to the Great Lakes. Increase these populations, and hypothetically the carp populations will go down too, right?

Maybe, but perhaps the frog, panfish and other smaller fish species populations will be impacted more than the carp population.

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#28 Guest_panfisherteen_*

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Posted 31 December 2009 - 01:16 AM

i agree with keepnatives, the minnows and small panfish as well as frogs (tadpoles) would be affected from the carp inferstation (them eating all that stuff whose name eludes me right now), and when the minnows and small panfish populations fall, then everything else except the carp will drop in population

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#29 Guest_DavidPT40_*

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Posted 31 December 2009 - 09:59 AM

Normally, when biological control is used, the predatorial species is chosen by strict criteria. It must only be able to prey upon and/or reproduce in the presence of the prey species. But with native species of fish, these requirements could be reduced. Asian carp could be combatted on different levels. They could be directly preyed upon, out-competed for food resources, and out-competed for nesting habitat.

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#30 Guest_centrarchid_*

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Posted 31 December 2009 - 10:29 AM

I am of the opinion the carps will make it into the Great Lakes basin. We may slow them down a bit and be able to control to a limited extent their population size (at great expense) but unless profitable use of the harvested crop is found, control may prove diffult to justify to tax payers.

The fishery the Asian carps (common carp, grass carp, goldfish, silver carp and bighead carp) threaten is in itself largely not native. Most of the "political will" is going to be focused on the most valuable components of the fishery. The most valuable components of the existing fishery (largely for sport) are based on salmonids native to the west coast. The existing fishery is part of the challenge the original natives, those that have not gone extinct, must deal with.

If (when) the Asian carps get more than a toe-hold in the Great Lakes basin, then I recommend we let a combination of existing predators / parasites in the system adapt to the invaders and help where we can with a selective commercial harvest. Do not add more crap (exotics to system) which could prove additive in the threats they impose on the existing stocks we are concerned about protecting. Establishing an equilibrium where at least some of the native stocks persist or regain lost glory must be expected to take several generations (human). As we mess around with moving species outside native, we need to start realizing impacts are not going to be short term, even with biological control organisms that might / will develope taste for non-target organisms.

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#31 Guest_DavidPT40_*

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Posted 01 January 2010 - 12:56 PM

I am of the opinion the carps will make it into the Great Lakes basin. We may slow them down a bit and be able to control to a limited extent their population size (at great expense) but unless profitable use of the harvested crop is found, control may prove diffult to justify to tax payers.

The fishery the Asian carps (common carp, grass carp, goldfish, silver carp and bighead carp) threaten is in itself largely not native. Most of the "political will" is going to be focused on the most valuable components of the fishery. The most valuable components of the existing fishery (largely for sport) are based on salmonids native to the west coast. The existing fishery is part of the challenge the original natives, those that have not gone extinct, must deal with.

If (when) the Asian carps get more than a toe-hold in the Great Lakes basin, then I recommend we let a combination of existing predators / parasites in the system adapt to the invaders and help where we can with a selective commercial harvest. Do not add more crap (exotics to system) which could prove additive in the threats they impose on the existing stocks we are concerned about protecting. Establishing an equilibrium where at least some of the native stocks persist or regain lost glory must be expected to take several generations (human). As we mess around with moving species outside native, we need to start realizing impacts are not going to be short term, even with biological control organisms that might / will develope taste for non-target organisms.

I agree with you, introducing more exotics would be a bad idea. However, the whole point of Fisheries Management is to adjust the ecosystem in a manner which achieves pre-set goals. The most basic of these principles is the bass/bluegill ponds. You can find thousands of websites on how to manage ponds by adjusting fish ratios, fish sizes, types of habitats, types of prey items. Of course it gets more complicated with a body of water the size of the Great Lakes.

But that does leave one question to mind. Why are Asian Carp so much better suited for our native waters than our native fish?

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#32 Guest_fundulus_*

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Posted 01 January 2010 - 03:14 PM

The Asian carps prefer eutrophic waters and are able to take advantage of the disturbed habitats and ecosystems that are typical of the Mississippi drainage. They lack predators keyed to their life history. The same could be said of starlings. They were only able to establish themselves in North America once carolina parakeets and passenger pigeons had been exterminated by European settlement, leaving huge areas of clearcut land with no competitors open for an opportunistic generalist like the starling. We could introduce European predatory birds, but would that make a difference in such a degraded habitat? The same question is faced with the Asian carps. I wasn't joking earlier when I suggested snakeheads; but of course that's a stupid idea, since we already have bowfins in at least some river systems, and a host of other obvious problems. A fisheries management approach is way too little way too late; the fisheries management people have already contributed to the collapse of marine fish stocks such as cod on the Great Banks so I don't think they have much to contribute anyway.

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#33 Guest_centrarchid_*

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Posted 02 January 2010 - 10:25 AM

The Asian carps prefer eutrophic waters and are able to take advantage of the disturbed habitats and ecosystems that are typical of the Mississippi drainage. They lack predators keyed to their life history. The same could be said of starlings. They were only able to establish themselves in North America once carolina parakeets and passenger pigeons had been exterminated by European settlement, leaving huge areas of clearcut land with no competitors open for an opportunistic generalist like the starling. We could introduce European predatory birds, but would that make a difference in such a degraded habitat? The same question is faced with the Asian carps. I wasn't joking earlier when I suggested snakeheads; but of course that's a stupid idea, since we already have bowfins in at least some river systems, and a host of other obvious problems. A fisheries management approach is way too little way too late; the fisheries management people have already contributed to the collapse of marine fish stocks such as cod on the Great Banks so I don't think they have much to contribute anyway.

The Carolin a parakeet and passenger pigeon would not have competited with starlings for much more than airspace with possible exclusion of the parakeet for nesting habitat. The starling specializes on extracting invertbrates from soil. The preferred starling foraging habitat during the breeding season is early succesional grassland in close proximity to naturally occuring cavities suitable for nesting. These criteria are met best in areas where humans maintain pastures / lawns based on cool season grasses and where trees have holes or buildings have eves suitable for nesting. Our native acciptors (Cooper's and sharp-shinned hawks) are every bit as capable of capturing starlings as their Eurasion equivalents. The area around my ponds provides an area where predator - prey interactions involving starlings can be watched with regularity. I like starlings, they are just as American as the rest of us!

What predator(s) are most important in the regulation of Asian carp? Bowfins do not occur in the same habitats where the Asian carp densities are highest, they simply look a little like snakeheads.

I agree fisheries managers will likely be unable to control the Asian carp problem. Effectively, the managers are not just the fisheries biologist paid for the task but are also EVERYONE ELSE affecting environment / landscape managenment, movement of the carp, harvest of carp, harvest of carp predators already present, and harvest of carp competitors. The problem is complex. Also an Asian carp management effort characterized as success by fisheries biologist might, and likely will be, deemed a failure by those interested in preservation of native fisheries or systems.

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#34 Guest_DavidPT40_*

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Posted 02 January 2010 - 11:33 AM

Well, there is only one real method I know of for totally destroying a fishery. Start commercial fishing for the carp. There has been success with marketing them to Asian immigrants. Also, they could be ground up as fertilizer, or their oils could be used for lubricants and cosmetics (like the Menhaden). But at the same time, I'd like to see native habitats (the limiting factor in reproduction in most rivers according to the American Fishery Society) boosted so that the niche left by the carp could be filled as their populations declined.

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#35 Guest_fundulus_*

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Posted 02 January 2010 - 03:32 PM

The preferred starling foraging habitat during the breeding season is early succesional grassland in close proximity to naturally occuring cavities suitable for nesting. These criteria are met best in areas where humans maintain pastures / lawns based on cool season grasses and where trees have holes or buildings have eves suitable for nesting. Our native acciptors (Cooper's and sharp-shinned hawks) are every bit as capable of capturing starlings as their Eurasion equivalents. What predator(s) are most important in the regulation of Asian carp? Bowfins do not occur in the same habitats where the Asian carp densities are highest, they simply look a little like snakeheads.

Since we destroyed the chestnut-dominated forests that passenger pigeons in particular needed, we completely set the stage for starlings: no dominant bird, radically altered habitat. And I'd guess that the Cooper's and sharp-shins aren't able to make a big dent in starling populations.

And DavidPT40 is right, restoring native habitats (and fauna) would be the best way to block Asian carps. Unfortunately it's a tall order, but hope springs eternal!

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#36 Guest_Moontanman_*

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Posted 02 January 2010 - 04:45 PM

Aren't the Asian Carp filter "type" feeders? Possibly we should reintroduce paddlefish into the lakes to provide some completion? I know there was some small talk about the possibility of reintroduction of paddlefish into the lakes. Wouldn't the carp compete directly with the paddlefish or am i thinking of the wrong carp?

Establishing a fishery for the carp does seem like a good idea, I saw a show a few weeks ago that stated the Asian carp are quite good to eat, they said better than native catfish and other river fish.

I know these are either unworkable or already thought of possibilities but lets not give up. The introduction of exotics is a big problem, I think far too much publicity has been given the aquarium releases in the past and the non aquarium release possibilities were ignored. So much effort is put into making sure aquarium fish are not released (and they should not) but it seems that when making money for fish farmers and or attracting fishermen is in the equation the danger of release isn't quite as scary until it is too late. I know the horse has already left the barn but what can be done to correct this problem? Do these fish rely on disturbed habitats that native fish cannot or will not live in? Do their numbers decline when habitats become more desirable to native fishes? What natives are they directly competing with? Is the problem direct competition or more general?

I remember carp almost taking over some polluted rivers when I was a kid, these rivers were cleaned up and carp numbers have gone down. Will making the lake waters more native friendly or restocking natives in areas where they have left or died out result int these Asian carp declining? I guess i am full of questions here.

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#37 Guest_farmertodd_*

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Posted 02 January 2010 - 04:47 PM

Actually, the hawks are quite adept at hunting starlings. I've seen formations of sharpshin hawks dive bomb starling flocks, just as I imagine they used to do with passenger pigeons (it's really something to see!). I think the problem here is that we reduced hawks so much with DDT etc that starlings didn't have any predators at all, along with all sorts of new crevices to breed, again, from our activities. Now that hawks are reaching their population thresholds for logistic growth, I think we're going to see a difference in starling populations in the Upper Midwest, and I'd be curious to see if birders are studying these effects.

But your point is well taken Bruce. I disagree with Centrarchid that starlings have even been nudged toward using their specialization since there were so many resources available due to the vacated niches. Starlings are a good generalist, and they've been quite able to live in the fullness of their functional niche (all the places they can live) rather than a discrete realized niche (the places they ARE living).

The same could be said about this entire argument in the Great Lakes. I'm not sure what part of an annual 10-15 million pounds of Coregonids from Lake Erie alone is unimportant in understanding this "invasion" problem... But managers, scientists and conservationists alike have looked sideways from this gap in the historic resources of the lakes, yet seem surprised other similarly adapted species (white perch, smelt, alewife) blow through and then find "lack of predation" and "lack of parasites" as the reasons? This is not a "Top Down" problem in the food chain, thus, there is no top down solution (salmonoids, for example).

I find bitter irony in the fact that we, as a species, are probably going to eat crow on our pet trouts when a disruptive member to the community comes in and effects bottom-up process (goby have to some degree). It will be honestly gross to see Lake Erie hypereutrophication swimming around as the jumping plague, but I am curious to see what can be gained in understanding from the invasion where resources are more fixed than in river systems.

If it really mattered that this suite of species stayed out, we'd fill the damned canal in. If I were king, it'd been done a long time ago. But I'm not, and it hasn't. The only way to stop these problems in the Great Lakes is to quit introducing species. The systems are PRIMED for invasion.

Todd

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#38 Guest_Moontanman_*

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Posted 02 January 2010 - 04:59 PM

I find bitter irony in the fact that we, as a species, are probably going to eat crow on our pet trouts when a disruptive member to the community comes in and effects bottom-up process (goby have to some degree). It will be honestly gross to see Lake Erie hypereutrophication swimming around as the jumping plague, but I am curious to see what can be gained in understanding from the invasion where resources are more fixed than in river systems.

If it really mattered that this suite of species stayed out, we'd fill the damned canal in. If I were king, it'd been done a long time ago. But I'm not, and it hasn't. The only way to stop these problems in the Great Lakes is to quit introducing species. The systems are PRIMED for invasion.

Todd

Todd do you think there is anything to be gained by trying to restock both currently native and by reintroducing extinct species to try and compete with he carps or is it just too late and we will just have to sit back watch the great lakes become carp ponds?

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#39 Guest_schambers_*

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Posted 02 January 2010 - 05:20 PM

Todd do you think there is anything to be gained by trying to restock both currently native and by reintroducing extinct species to try and compete with he carps or is it just too late and we will just have to sit back watch the great lakes become carp ponds?

I think the ecology of the lakes is too screwed up to just 'reintroduce' species. I think if the lakes were healthier, they would already be there. As it is, there are unoccupied niches ready and waiting for invasive species to exploit.

Edited by schambers, 02 January 2010 - 05:21 PM.

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#40 Guest_Moontanman_*

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Posted 02 January 2010 - 05:23 PM

I think the ecology of the lakes is too screwed up to just 'reintroduce' species. I think if the lakes were healthier, they would already be there. As it is, there are unoccupied niches ready and waiting for invasive species to exploit.

You don't think over fishing could have been responsible for some fish in the lakes disappearing? I for one would like to see those unoccupied niches filled by something other than carp.

Edited by Moontanman, 02 January 2010 - 05:25 PM.