Thread: Ask the Biologist

Hey Craig, I was wondering if you could elaborate on this copper ionization treatment they are considering at cheney lake for dealing with the zebra muscles?

Originally Posted by cannon14

Hey Craig, I was wondering if you could elaborate on this copper ionization treatment they are considering at cheney lake for dealing with the zebra muscles?

cannon14,

You may have already seen this, but here is a link to video on the Cheney issue from a Wichita tv station. Zebra Mussels

.

This process has been used at power plant intakes to reduce zebra mussels so it is not a totally new approach and appears to be effective. From what I hear, it has not previously been used in public water supplies--why?? I don't know. There are other options of control such as chemical injection of materials such as chlorine to keep lines free of zebra mussels but these projects are also quite expensive and have their own issues for consideration.

From what I gather, two copper plates will have electricity put through them which will give off copper ions. The plates will be placed inside the water intake. The amount of copper is very minute and will be within acceptable copper levels for drinking water. This introduction of copper is enough to shut down the zebra mussels that are attempting to colonize the intake and transfer lines from the lake.

Wish I could "elaborate" more, but my strengths are not in the water treatment arena! I hope this helps answer some of your questions!

Let me know if you need more info and I'll see if I can dig something up.

Thanks.

Thanks for contributing Mr. Johnson! This is a cool thread! I just noticed it (at least i think I just noticed it -- it's been a rough winter).

I have a question that is purely within a speculative realm, and I'll understand if you don't feel inclined to offer such conjecture. With that said, what do you think would happen to fish populations, in terms of the diversity and density of various taxa, if KDWP ceased stocking programs. Would extant diversity shift profoundly? Remain static in terms of ratio but drop in density perhaps?

I don't know much about what species of fishes are truly indigenous to Kansas, and also realize public works, such as impoundments, have created aquatic habitats that didn't really exist before -- i.e. turning ephemeral streams and water courses into reservoirs.

Thanks again for adding to the site and sharing your knowledge!

Originally Posted by georgem

Thanks for contributing Mr. Johnson! This is a cool thread! I just noticed it (at least i think I just noticed it -- it's been a rough winter).

I have a question that is purely within a speculative realm, and I'll understand if you don't feel inclined to offer such conjecture. With that said, what do you think would happen to fish populations, in terms of the diversity and density of various taxa, if KDWP ceased stocking programs. Would extant diversity shift profoundly? Remain static in terms of ratio but drop in density perhaps?

I don't know much about what species of fishes are truly indigenous to Kansas, and also realize public works, such as impoundments, have created aquatic habitats that didn't really exist before -- i.e. turning ephemeral streams and water courses into reservoirs.

Thanks again for adding to the site and sharing your knowledge!

georgem,

Great question!! I don't know if I will be able to fully answer it as ceasing statewide stocking efforts impacts MANY types of waters from 1 acre ponds to 16,000 acre reservoirs and the effects would quite variable.

The reason for stocking fish in Kansas waters is to maintain densities of "fishable" populations, or populations of fish that are dense enough to provide good angling opportunities for that particular species. With that being said, stopping the stocking a particular species would result in a drop in the density of that species and in some cases, a change in other populations as well. For instance, if I would quit stocking saugeye in Chase State Fishing Lake, the saugeye population would cease to exist in 8 or so years as these fish do not naturally reproduce to provide a self sustaining population. No stocking, no saugeye! I stock the saugeye not only to provide additional angling opportunities but mainly to provide predation pressure on the white crappie population at the lake. Historically, Chase SFL was cursed with a stunted crappie population. Saugeye were stocked to eat white crappie decreasing their density. As density of the crappie fell, growth rates improved, and average size increased providing a much better crappie population for the angler. So, stop stocking saugeyes at Chase SFL and the saugeye disappear over time and the crappie become too numerous without sufficient predation and stunt out. Stunted crappie populations negatively effect other species as well such as black bass as they compete for space and food sources. Stunted crappie populations decrease growth rates of the young black bass leaving fewer larger and more desirable bass for the angler. This is just one scenario of ceasing stocking. Each lake would have its' own story depending on the current status and history of the water body.

Some species are stocked for their desirable effect on one species to benefit another such as the saugeye/crappie scenario and also wiper. Wiper have been used to change size distribution in gizzard shad populations to sizes that are more usable by game fish such as crappie. So in some instances, canceling wiper stockings would hurt crappie populations.

So long term effects of not stocking game fish in Kansas waters? There would be a shift towards fewer sportfish that angler desire, a shift towards fish sizes not desired by anglers (smaller), and an increase in species not found desirable by anglers (roughfish). A lake can only support so many pounds of fish per acre, and those pounds can either be made up of desirable species or undesirable species.

I have just scratched the surface of this topic for you. I hope this provides you some usable info. If you want more info on this topic, feel free to give me a call. I can talk a lot faster than I can type!!

Craig,

Thanks for everything you post.

Quick question, since you work El dorado how has the zebra mussles affected the brush habitat in the lake? Do Crappie and Bass still use the shollow brush piles like cedar or willows or have the Zebra's choked them out of those?

Thanks
Nick

Originally Posted by Springhill Duckman

Craig,

Thanks for everything you post.

Quick question, since you work El dorado how has the zebra mussles affected the brush habitat in the lake? Do Crappie and Bass still use the shollow brush piles like cedar or willows or have the Zebra's choked them out of those?

Thanks
Nick

Nick,

The zebra mussel population peaked in 2006 at El Dorado and at that time brushpiles were VERY colonized with zebra mussels and this had to impact the quality of the habitat. There were no "small branches" on a pile as everything in the water had a dense covering of zebra mussels. Brushpiles were much more solid as the zebra mussel shells filled in the voids. This would reduce hiding areas for fish. We had our first zebra mussel die off mid-year 2007 and the adult zebra mussel population density dropped of dramatically. It is now possible to see rocks on the shoreline instead of coatings of zebra mussels. Brush in the lake is not completely covered with zebra mussels and line breakage due to line abrasion from the zebra shells is not currently a problem. We still have the zebra mussels in the lake but at a MUCH lower density than 2006. Crappie are currently using the brushpiles and if you happen to snag a branch and pull it to the surface there are very few noticeable zebra mussels present.

So in short, at very high zebra mussel densities I believe fish habitat was impacted at El Dorado. Currently, zebra mussel densities are low enough that they don't appear to be impacting the fish habitat.

Craig, When do the gizzard shad spawn in our Eastern Kansas reservoirs? We running up the river in a Central Kansas lake and graphed huge quantities of fish. We tried very hard to catch something but no bites we could feel fish running into our lines. This was last week and the water temp was between 38 and 40. Do you have a guess or idea as to what kind of fish these were. Thanks for your time.

Hey Craig, this is such a nice thing you are doing. Since you were talking zebra mussels, thought I'd ask about blue cats. Have they determined that stocking blue cats can be effective at managing zebra mussels?

Originally Posted by Blackdog40

Craig, When do the gizzard shad spawn in our Eastern Kansas reservoirs? We running up the river in a Central Kansas lake and graphed huge quantities of fish. We tried very hard to catch something but no bites we could feel fish running into our lines. This was last week and the water temp was between 38 and 40. Do you have a guess or idea as to what kind of fish these were. Thanks for your time.

Blackdog40,

I apologize for the delay in my reply. The walleye spawn has begun in Kansas and field work is keeping me busy so my "computer time" has been reduced.

Gizzard shad spawn in May and June in Kansas. In the larger reservoirs the spawn may be spread out a little as the shad will typically spawn earlier in the upper reaches of the lake as the water temps warm a little more quickly. This works out good for the game fish as it is beneficial to have the gizzard shad spawn spread over a long period of time as this produces more diversity in the sizes of shad available to predators. We want shad available early in the year so young of the year game fish will have a good food source but we also want late spawned shad so there will be small shad available over the winter months for the smaller/younger predators. Shad are capable of outgrowing their usefulness to predators if they spawn too early and get ahead of the predators. Having high densities of shad in a lake isn't always good enough, as the shad have to be of the correct size to benefit the game fish.

You may have been seeing roughfish on your sonar. Buffalo will sometimes school up tightly and they do not often take a line. It's hard to say for certain what species of fish they were.

Hope this helps.

Originally Posted by PK Buggers

Hey Craig, this is such a nice thing you are doing. Since you were talking zebra mussels, thought I'd ask about blue cats. Have they determined that stocking blue cats can be effective at managing zebra mussels?

Stocking blue catfish will not control zebra mussel densities. The zebra mussels are just too prolific to be kept in check through predation.

I stocked blue catfish in El Dorado to create a positive out of a negative. Blue cats do feed upon zebra mussels during the summer months so utilizing the zebra mussels as a blue catfish food source to create additional angling opportunities was an option. Many Kansas species eat zebra mussels including channel catfish, freshwater drum, common carp, and redear sunfish (as well as some others) but we cannot get enough predation pressure from these fishes to control a zebra mussel infestation. I have seen blue cats at El Dorado that were completely stuffed full of zebra mussel shells. I've also seen carp and drum that were full of nothing but crushed up zebra mussel shells. I checked some carp at Cheney last fall and they too had been feeding heavily on zebra mussels. They just can't eat enough zebra mussels quickly enough to decrease the mussel densities.