Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? selective killing of gizzard shad

I believe that's Threadfins.

I came up with the same, Theo. The article I posted says winterkill of gizzard shad is due to low oxygen. Apparently they're less tolerant to low DO than other fish?

Thanks guys: I read lots of stuff about g.shad: they are fragile, like die from quick change in temperature. I have buried many that wash up here and there on the shore line, it is always the g. shad, not the other fish.

There were some articles like "Nutrient Recycyling by fish supports more primary production as lake productivity increases"
they like turbid water which we have since 04.

The conclusion was that this fish is really contributing to the nutrient load by stirring up the bottom, and creating its own waste, and hurting the other fish by eating all the zooplankton,
would you agree with that theory?
Lynda

Yes to a certain extent. The thing to keep in mind is that the fisheries scientists who surveyed the pond are the ones who actually saw the fish and the water and the whole system interaction. We only have your posts wrt what they said and what you have seen. They are in a better position to tell what is needed. We can tell you what we think and offer things to consider. There are 3 basic ways to approach the situation :

1. Do nothing and the results will get worse.
2. Kill the pond off and start over.
3. Add predators and reduce the GShad population through some combination of actions.

So nice to see I made it to Lunker Status. It will be a year tomorrow since my girlfriend and I took over by having the first election in this subdivision ever, having to manage 6 lakes to fix one. Tomorrow is the annual meeting where there are 2 more people running for office, so we have started something good. Don't want to see the other lakes go the way of this one, we just got the crappy lake, or the one that went first. Kind of like a pyramid scheme, first people in got nice beautiful lakes for little money. Then they did not take care of them. Paid tiny dues, grew older, stopped using the lakes. The treatment rules changed (no more aquashade) so it is like if you live by putting stuff in that maybe you shouldn't at the rates I think were used, then when you stop, all the problems surfaced, no longer masked. The lake was good the 1st three years for me, then went to crap. Green bubbles that stick to my skin in the morning when I do the temp, level and clarity. But, things are going to get better, they already have. Without that fish survey we had to fight for, we wouldn't know about the g.shad, and we have spent a year learning everything about lakes. Meeting super great like minded people. Very worthwhile effort.
Thank goodness for this super site and all you good people.
Lynda
The fisheries haven't been managed. Some fish were stocked in 1988, and that was that. The gravel pits were here before the houses were built, so there must have been fish here then too.

ok, I forgot my password, but I can't find the navigation island to edit profile to reset it. Help.

I'm not sure I understand the problem, 2cat, but if I do, it's "My Stuff" and then "My Profile".

Wouldn't drawing the pond down concentrate the number of G shad allowing predators to feed on them more effectively? With a greater concentration of G shad wouldn't their natural population crontrol kick in and cause them to stop breeding?

The other options of control sound more fun to me. Adding more LMB always sounds inviting, but no one mentioned that overcrowded G Shad will eventualy stop breeding all together. If they want the G shad completely gone wouldn't concentrating their numbers and stopping breeding be the best option?

I may be way off with my thought process on this one but I am just wanting to get things straight in my own mind (just in case my pond ever has this problem).

"Wouldn't drawing the pond down concentrate the number of G shad allowing predators to feed on them more effectively? "

Yes. But if there are not enough predators the reduction will be less than needed. Plus the predators still can't eat a 20 inch 2 lb GShad.

"With a greater concentration of G shad wouldn't their natural population control kick in and cause them to stop breeding? "

Possibly but only if the water were down just before and during spawning and only for the time the water is down. When it goes up they will "fill the space". Not sure you want a permanent reduction in pond size.

"If they want the G shad completely gone wouldn't concentrating their numbers and stopping breeding be the best option?"

Removing GShad or continual suppression of them with predation to the point they can't take over the pond are the only ways I have heard of where they don't get to big for predation and fill-up the pond biomass.

Drawing down the pond just before winter (pond low during winter) up north is a good way to create a winter kill of everything including the GShad . Draining the pond would do the same as would rotenone.

Drawing down the pond during spring and concentrating the GShad , finding them with sonar and gill netting them along with increased predation would help.

Thanks ewest. I appreciate your concise answer. I assumed there was a reason no one else mentioned that G Shad stop breeding in crowded conditions.

Back to the drawing board.

More great thoughts and answers you guys, thanks. You have to understand that I am living in Stepfordville here in Michigan. I want to put a pump in our overflow and drain just a few inches out for the winter, and people are freaked out about that idea, it never crossed anyone's mind that it would decrease erosion in 30 years. There are about 35 houses on this little lake/pond which has been a swimming lake all this time. Our DNR guy says he only has one other lake he knows of with this problem, I bet if we had a fish survey on all our other 5 lakes we would find they have the g.shad too. Will have to get all the people to report any dead fish that wash up, so we can find out, I was finding them for 3 years but didn't identify them until this year. I'm a much smarter Lake Rep now, have devoted all my spare time to learning all things water. I'm going to write down all these great suggestions and run them by our Board and the DNR guy, he wants us to kill all the fish. I am resisting that suggestion as I feed the bass and bluegill little snacks every morning & evening. They follow me along the shore, we are attached at this point. There is one bluegill that has a big chunk out of his back, and he is a little faded in color compared to the others, I call him Gashy. If we have to kill them all, we will have to harvest the huge Bass and put them in another lake, I couldn't stand to kill them.
Lynda

Michfish stocked Hybrid striped bass in Michigan. I'd try the HSB before more drastic measures.

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Main=12097&Number=137642#Post137642

ive always heard musky and pike are not good for ponds
they kill for the fun of it, is this true?

Eric I have gizzard shad in my pond but have never seen one larger than five inches. How would you determine if you had too many large gizzard shad? Would you know by the fact that they cause some type of visible problem? This year I have seen fewer shad of any kind than last year. It makes me wonder if the hsb have really done a number on them this year?

I don't have the info in front of me, but I'm pretty sure low doses of rotenone can select for the gizzard shad. You might also check on the availability of a chemical called Fintrol. While working for the state, I watched one of our hatchery managers apply it at low doses in shad contaminated catfish grow-out ponds. He whacked the shad and the catfish were unharmed. I have no idea what the dosage was or even if Fintrol (spelling may be wrong) is still available, but the gizzard shad were less tolerant to it than other species. Because of this, the low dosage was used to select for and only kill the shad.

Some research on using these piscicides at low dosages to select for shad only might be worth it to you. I know its been done. I wish I had more technical info for you, but perhaps this limited info can point you in the right direction.

Great info Shawn and I also know that selective control by both strength and location is used.

James if you look hard and can't find a GShad over 6 inches and the rest of your fish population is where you want it then I would not worry about the GShad. Keep a close eye out for a reduction in fish quality or increase in GShad size as an indicator that you need to do something about them.

Thanks

Shawn yes rotenone will work on low dosage. I have yet to do it but have it in arsenal since recommending gizzard to clients wanting double digit bass in right circumstance.