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The game may be over: Asian carp beyond electric barriers


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#41 Guest_farmertodd_*

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Posted 02 January 2010 - 05:37 PM

I agree with Susan, there's too many feedback loops to just reintroduce things. If we want any kind of recovery (and it is truly REHABILITATION not RESTORATION), we need to cut off the inputs that perpetuate this modification and stop introducing species. We need to reach some sort of artificial equilibria (and I use that word extremely cautiously, because I don't really believe in natural equilibrium) that we're comfortable with and figure out where we're at then. Honestly, I think 80% of the species level issues in the Great Lakes would work themselves out if we did absolutely nothing besides significantly reducing cultural inputs - fertilizer, sewage, sediment, dredging and armoring. But I'm not hopeful that is going to happen, and as such, we leave it a system in flux, primed for invasion.

Todd

#42 Guest_centrarchid_*

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Posted 02 January 2010 - 08:10 PM

Now I am grumpy.

Farmertodd,

Please read the following "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."

You responded with "Actually, the hawks are quite adept at hunting starlings".


To clarify, at no point do I say the native acciptors are incapable of capturing starlings. My observations are of individual hawks hunting starling flocks of no more than a couple thousand individuals. They (sharp-shins) take a starling with almost every encounter, although several stoops and chases through the brush may be required to make a catch. The starlings try to stay above the hawk and if they fail at that with the hawk in pursuit, the starling tries to break line of sight. The problem is that once a catch is made, the starling flock moves away and the sharp-shin does not follow. Therefore, the hawk is unable to keep pressure on a single flock and the predator seems not to be inclined to direct all effort on the starlings when alternatives can be found. Bad characteristic for a regulator predator / parasite.

Now getting back to revelance with thread. You state "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."

I am not in a major migratory flyway for the acciptors as you likley are so I do not at this time see large numbers of the predator. It is very possible if sharpshin abundance is high enough a fundamental behavioral shift might follow where groups of sharpshins might follow the starling flocks as well as flocks of redwing black birds, American robins and common grackles. As for the reason behind low sharpshin abundance, a more plausible reason is the abundance of it larger relative the Coopers Hawk. Latter consumes sharpshins and denies breeding territories if Cooper density high. Coopers are more of an edge species, so do the math on edge versus deep forest when most forested areas are fragemented. Potential native predators on Asian carps may have their own complex interactions which can complicate management strategies. Also, some predators on Asian carps may have to reach some critical density before they become an effective regulator. A real problem will be had if the predator supports a fishery of some sort and the fishery pressure keeps it below that required to be an effective regulator. Bluegill / largemouth bass assemblages can be pushed to produce many small bluegill if bass abundance maintained too low. This may be as imporant for the persistance for many aquatic invasives as habitat modification.


And another point involves the following where you say "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).

Todd, take the time to go walking (or hunting) in the middle of old growth forest or intact prairie either during the breeding or flocking seasons for starlings. I bet you can not find any of the "ubiquitous" starling. Where you are seeing you starlings is in habitats that are heavily modified or in very close proximity. Last check I made, nearly 90% of the American landscape is modified for some purpose or another and soil is exposed annually or is covered in something like fescue (a cool season grass) that is either grazed or mowed frequently. Starlings do not like tall grass for foraging.


Yes, our aquatic habitats are primed for invasion. Even if introductions stop and the canal is closed, climate change is likely to cause major problems for native species in the lakes that are already on the southern limit of their range. The Centrachidae are just waiting for a temperature increase of just a couple degrees so they can have a shot at being like the cichlids of the African rift lakes.

I would chew more butt my monitor is dying and my wife says I am long winded!

#43 Guest_schambers_*

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Posted 02 January 2010 - 11:15 PM

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.


If over fishing is an issue, then we need to address that. Is it being monitored? I know there are limits for sport fishermen, but what about commercial fishing?

I'm not as educated as I'd like to be, I just read stuff. Today I read an article in my local paper about dredging plans for the Maumee River. The Army Corps of Engineers "has asked the Ohio Environmental Protection Agency for permission to dredge up to 2 million cubic yards annually from 2010 through 2012. About 1.9 million cubic yards of that could be dumped into the lake under the Corps proposal. That means the Corps would be required to landfill only 5 percent of what it digs up." That's up from their usual 600,000 cubic yards (per year) of sediment dumped in Western Lake Erie near Toledo. They dredge the river to keep it deep enough for shipping. I guess they dump the sediment back in the lake because it's cheaper than paying to dump it on land somewhere.

Are any of our government agencies working on solutions to keep the silt out of the river in the first place? Or do we just keep paving over or plowing up everything in sight?

#44 Guest_farmertodd_*

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Posted 03 January 2010 - 09:02 AM

Centrarchid,

I owe you an apology... I looked back through, and it appears that I should NOT hit the crack pipe before I start writing something :) I don't disagree with anything you've said. I don't know where I got off the rails.

Susan,

It's not silt that's filling up the shipping channel (although the silt isn't helping anything)... It's dominated by lateral sediments that are filling in from the sides. It's kinda like when you were a kid and you built sand castles at the water's edge, and you'd try and build a moat around it, but it would keep filling in as a shallow depression - the material all slid in from the sides. This in large part is why we've had to armor the entire western end of the lake and why we've had to put in all these control structures to maintain anything resembling a coastal wetland.

It also perpetuates cuts (headward erosion) upstream in all the rivers, sometimes miles upstream. It's kinda neat, I can show this with my stream table. If I dredge "lake sediment", it all fills back in and we see the most migration in the channel upstream a couple feet (which at that scale is pretty profound).

Todd

#45 Guest_az9_*

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Posted 03 January 2010 - 09:38 AM

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?



I would bet the Asian carp have a much higher fecundity than the paddlefish so the paddlefish may lose in competition.

#46 Guest_Moontanman_*

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Posted 03 January 2010 - 11:22 AM

I would bet the Asian carp have a much higher fecundity than the paddlefish so the paddlefish may lose in competition.



I think you may be correct there for sure, we would have to stock many thousands of paddlefish to give them even a small chance. To be honest I'm not sure about the life cycle of the original Lake paddlefish, does anyone know if they must go up stream to specific stream like salmon? Do the fry need to be "imprinted with a home stream" before they will attempt to reproduce?

#47 Guest_Moontanman_*

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Posted 03 January 2010 - 11:25 AM

If over fishing is an issue, then we need to address that. Is it being monitored? I know there are limits for sport fishermen, but what about commercial fishing?



I am pretty sure the paddlefish is already extinct in the lake, other fish may very well be depleted to the point the population is no longer viable. Limits would not help these fish.

#48 Guest_Moontanman_*

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Posted 03 January 2010 - 11:29 AM

I agree with Susan, there's too many feedback loops to just reintroduce things. If we want any kind of recovery (and it is truly REHABILITATION not RESTORATION), we need to cut off the inputs that perpetuate this modification and stop introducing species. We need to reach some sort of artificial equilibria (and I use that word extremely cautiously, because I don't really believe in natural equilibrium) that we're comfortable with and figure out where we're at then. Honestly, I think 80% of the species level issues in the Great Lakes would work themselves out if we did absolutely nothing besides significantly reducing cultural inputs - fertilizer, sewage, sediment, dredging and armoring. But I'm not hopeful that is going to happen, and as such, we leave it a system in flux, primed for invasion.

Todd



I agree that habitat restoration seems unlikely, introductions of more exotics seems far more probable. I would just like to see paddlefish reintroduced, probably be about as successful as tilting against windmills but it's an honorable thing to restore rather than destroy.

#49 Guest_DavidPT40_*

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Posted 04 January 2010 - 06:29 AM

On an slightly different note, I read that crayfish are voracious predators of zebra mussels, with adult crayfish being able to eat 100+ mussels a day. Paddlefish cannot be reintroduced to the Great Lakes because the zooplankton levels are too low (due to zebra mussels feeding on phytoplankton).

#50 Guest_Burbot_*

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Posted 04 January 2010 - 01:45 PM

On an slightly different note, I read that crayfish are voracious predators of zebra mussels, with adult crayfish being able to eat 100+ mussels a day. Paddlefish cannot be reintroduced to the Great Lakes because the zooplankton levels are too low (due to zebra mussels feeding on phytoplankton).


so we can stock up on rusty crayfish to eat zebra mussels and paddlefish to compete with carp, and maybe something else to eat carp.

Good Luck.

pardon my pessimism here, but I just don't see the solution in these suggestions. i think the title says it all.

#51 Guest_Moontanman_*

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Posted 04 January 2010 - 11:49 PM

so we can stock up on rusty crayfish to eat zebra mussels and paddlefish to compete with carp, and maybe something else to eat carp.

Good Luck.

pardon my pessimism here, but I just don't see the solution in these suggestions. i think the title says it all.



I think your pessimism is justified, it just seems a shame not to try.

#52 Guest_farmertodd_*

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Posted 05 January 2010 - 09:42 AM

It would be a shame to not try, but I don't think the money is well spent at the species level. What needs done is study of where things happen that are not expected, and the underlying reasons for WHY they're happening there so we can replicate it all over the place.

For example, we're looking into the mechanisms for how at least 4 species of Unionid mussels are doing, um, WELL, in the near shore, open lake environments of the western basin of Lake Erie in spite of being smothered in zebra mussels, for example.

How much money has been spent maintaining that barrier? Can you imagine what could get done if that money was channeled toward habitat IMPROVEMENT instead? Esp improvement of ecosystem engineers like the native mussels? They'll do a whole helluva lot more than any paddlefish will ever do :)

I'm glad to see the states are suing to close it.

Todd

#53 Guest_centrarchid_*

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Posted 05 January 2010 - 11:20 AM

Yes, it is a question of habitats not individuals species. At this time I feel blocking a the flow between the Mississippi drainage and Lake Michigan through Chicago also prudent.

How can more groups / individuals get involved with habitat improvement and restoration? Presently, it appears to be the job of governmental entities only with the public kept on the sidelines without a real feeling of ownership or stake in situation. We could have shoreline of lakes designated to interested groups that clean and monitor as done with many stretches of highway where road sides are cleaned up. Assuming this is not already being done.

I like the native mussels and see their value as filter feeders. Could the public be excited about these organisms (charismatic mesofauna) to promote involvement dispersal programs in the lakes. I realize most of the natives require fishes as dispersal agents and this would eventually saturate suitable habitats, but dispersal could also be enhanced by transplanting juveniles such that upon reaching maturity, they would be much more likely to be in close proximity of a suitable partner for mating. The public could help with dispersal by providing boats.

The paddlefish need help as well and should not be discounted even though they may not be suitable as a keystone species for plankton management. They may never be able to control plankton but over the coarse a few decades they could be managed up to the point where they could support a fishery and be a safety net for the species in the event the riverine populations continue to decline.

#54 Guest_Newt_*

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Posted 05 January 2010 - 11:36 AM

I don't know about the Great Lakes, but here in TN there are NGOs such as Tennessee Scenic Rivers Association and scout groups that perform stream cleanups. Getting boaters/anglers involved is a good angle if the logistics could be figured out. A lot of outdoorsmen seem to have knee-jerk negative responses to "environmentalist" initiatives, but might respond better if the fisheries/water quality improvement aspect is stressed.

How does one "plant" mussels? Is it something that laymen could do effectively?

#55 Guest_centrarchid_*

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Posted 05 January 2010 - 11:55 AM

Process much like the evil bait bucket introductions implicated with many dispersal events with exotics.

Planting / seeding mussel term I learned from oyster production. The young oyster effectively stays where you place it, much like a zebra mussel. Our native freshwater mussels are mobile once they become benthic but they are slow and in my experience are picky about what substrates they will burrow through. When I plant native mussels, I move them a distance over substrates they avoid or put them in an elevated "box garden" they can move around in but can not exit or enter under their own power. Yes, anyone can move the mussels about. The culturists / hatchery / biologist tending a strong natural population could harvest juveniles from substrate and give to individuals that would then take the juveniles to designated suitable habitats. In some instances, the animals could just be dumped overboard at the appropriate location. These days with GPS units, anyone could motor to the appropriate sites or in some cases drive around the lake.

#56 Guest_BTDarters_*

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Posted 09 January 2010 - 07:43 AM

At the risk of getting this thread waaaaaayyy off-topic, shouldn't only the proper agencies or properly permitted individuals transport and "plant" organisms from one water body to another? I don't think that we want everyone and their brother moving organisms from one waterbody to another.

Brian

#57 Guest_farmertodd_*

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Posted 09 January 2010 - 10:31 AM

Even the biologists... In an old landscape like MO, for example, it would be irresponsible to move any organism across basins without first looking to see if there's if there's any isolating reproductive barriers. With the saddled darters there, folks have found that molecular test of species hypotheses are yielding distinct groups down to the river (see Switzer & Wood 2009 or this short article on erythrozonum).

If the fish are reproductively isolated, this can imply the mussels are as well.

The public's role, outside of utreach & discovery programs (which needs to be more prevalent) is to manage the landscape sustainably, imho.

Todd

#58 Guest_centrarchid_*

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Posted 09 January 2010 - 12:38 PM

At the risk of getting this thread waaaaaayyy off-topic, shouldn't only the proper agencies or properly permitted individuals transport and "plant" organisms from one water body to another? I don't think that we want everyone and their brother moving organisms from one waterbody to another.

Brian

My suggestion was specific to the mussel situation in the great lakes. Private individuals would work under supervision of government agencies (effectively permitted). Public involvement would simply help with logistical limitations of the agencies involved so dispersal could be done in one day. One of agencies jobs is to make certain stocks are not crossed unless agancy decides that is best option.

#59 Guest_smbass_*

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Posted 09 January 2010 - 11:00 PM

In the past couple weeks all Great Lakes States have filed a joint lawsuit (except IL) against the Army Corps Enginneers to have the canals filled in... We'll see where that goes and maybe even IL will join in since every other state has joined in already.

#60 Guest_panfisherteen_*

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Posted 10 January 2010 - 12:50 AM

good, even if a couple carp get into the great lakes it will be a lot easier to attempt to stop them than to simply keep the canals open and let and unlimited amount enter the great lakes and then fight them.




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