Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Eliminating Threadfin Shad

I'm working on a plan to do rotenone treatment to get rid of threadfin shad in 7 ac pond, which involves several property owners. We've had a biologist assisting with calculating proper rates, etc. to selectively manage the shad out. I have applicators license so no issue procuring the product. However I do have one question that I'm hoping someone with rotenone experience can assist with: What should I expect in terms of the fate of the dead shad? Should I plan to remove them from the pond or can I expect scavengers to quickly take care of them? Some of the property owners are concerned about the smell, ugly sight of dead fish, etc. Location is central Alabama. Timing hopefully December. There will be catfish, bass, and crappie remaining after the treatment. I hope these remaining fish, along with birds, etc. will help dispose of the dead shad.... just not sure how much. Any insight would be appreciated.

Thanks.

dbhelm I am curious to why you want to get rid of the shad?

the reason I ask is my pond mgt company said I should consider
adding threadfin shad in my 4 acre pond.

This is directly from my survey/lake report:

"The threadfin shad is one of the most important forage species in
many lakes. They grow quickly, spawn early in their life cycle and
reproduce prolifically. These qualities make these shad great forage
for bass. Threadfin school in open water and swim slowly, which
makes them easy prey for bass. Threadfin tend to do better in fertile
(green) water because their food is the phytoplankton that causes the
water to become green"

They are threadfin and not gizzard shad right?

From what I know of rotenone most of the dead fish will float. If a pond that size is overrun with tshad there will be an astounding amount of dead to deal with. I would consider some kind of net to get them to the edge of the pond (or a windy day), then maybe a skidloader or small tractor and load them up and take them away. I cant give any info on smell, but I think it would last a week or so if I was guessing. Also scavengers will do their part, but not sure how fast they could clean up the mess.

If the pond is close enough that houses will be smelling dead fish, I would probably try to deal with them. If it is a few miles from houses etc. I would just get the deads out of the pond and let nature take its course.

Also not sure of your situation, but if you have a way of lowering the water level of the pond it will lower your chemical needs.

So you are trying to kill just the shad? I heard that was possible, would love to hear a report of how it goes and how many other fish stress/die.

And I agree with Zep, never heard of anyone getting rid of threadfin....now gizzards on the other hand..."guess it all depends"

We have an overabundance of threadfin shad which has upset the bass/bream balance we would prefer to have in the pond.

dbhelm, Im curious what is your plan once you kill the shad. As far as new stocking or just let it be? The pond dynamics are going to change rapidly. Makes me wish I was a fish biologist!

Biologist who analyzed the pond says we do not have enough bream.

O.K. What's the goal for the BOW?

What size are the shad that you are seeing?

I've never heard of selectively using rotenone to only eliminate one species.

How are the Tshad reducing the bream (BG?) population?

If you have an overabundance of threadfin shad (not gizzard shad) I would think that someone would pay you a good bit of money to try to harvest them to relocate them to lakes that need more forage.

I appreciate all of the responses, and want to follow up specifically on this one.

If you are interested in harvesting and relocating threadfin shad from a 7-acre pond in Central Alabama please email me:
dbhelm at charter dot net

Thanks.

Shad (and carp) are susceptible at rates as low as 0.1 ppm. The selectivity is pretty well documented in the literature (and on the product label).

Thanks again for the replies.

I know other posters have tried to hint at this but I am just too curious: How can threadfin shad be too abundant and what would that abundance have to do with bluegill?

It seems to me like over-abundant threadfin means your bass and bluegill are feasting and loving life! We constantly hear about pond owners who have stunted bass growth and not enough forage, I have never seen someone say that they have TOO much fusiform food for their predators. I'm not saying it's impossible, I have just never heard of another occurence and I am dying for more details!

Would stocking more bluegill or bass be an option? Bluegill and Largemouth have very high ferucundity (sp) and are far more likely to require harvesting than supplemental stocking. If more bluegill are needed this seems to me like the best way to do it.

Could it be that your largemouth are so big from gorging on the threadfin that they have also dented the population of large brood-stock bluegill? If so I don't think removing some shad will do anything other than starve your bass. If the largemouth are putting that kind of a hurt on your bluegill population then you might have the perfect pond for Gizzard Shad to be introduced! Either way I am jealous!!

Any chance we can see the report suggesting TShad eradication ? Or can we get the rationale behind the suggestion?


TShad generally do not compete enough with BG to cause a problem especially in small waters.

All sounds fishy

I should add that the only time I have seen that recommendation (nuke tshad) is on a lake that wanted to get rid of them so they could stock GShad for trophy LMB goal (lots of bass over 5 lbs existed). The reason is TShad have been shown in some situations to suppress GShad recruitment (reproduction). I would like to learn if there are other reasons involved.

dbhelm, I've just never heard that nor have seen the documentation. However, I'm not an applicator and there are a lot of things that I can always learn more about.

It seems to me that, even in low amounts, it would affect yoy fish of other species. But, again, I'm not a trained applicator.

It would certainly have to be done carefully. Since I take a shotgun approach to just about everything, I wouldn't be the one to do it.

DD1 folks have done rotenone apps for selective removal of Gshad. In fact I shocked Ray scott's Presidential lake after he had performed a selective treatment. Yes it killed some bass and other species but it also killed thousands and I mean thousands of Gshad. The bass bounced back with great recruitment of bass first time in a couple of years.

Now to these recommendations. I cut my teeth in my start of my career fighting clients on tshad. The thoughts were that tshad compete with bluegill for food. Truth is when lakes have tshad the bluegill population is much higher due to lack of bass predation. In other words more bluegill survive due to bass eating tshad. So these recommendations are not common I will say that. If your goals are good bass growth you need both shad and bluegill. Stock more bluegill don’t rid of shad. Something may be limiting your bluegill but don't think it is Tshad. Secondly you better know what you’re doing. It is tough to apply just the right amount evenly to kill shad and not kill other species. I probably would not even do it for a client in fear of killing his bass and I do this for a living. Just my two cents.

dbhelm - I too would like to see the report, data, and rationale that concluded the tshad were influencing the BG recruitment. My first thoughts were: 1. what was the estimated density of tshad to be considered too abundant? 2. If they are too abundant - why? look for that cause. 3. Since tshad are prolific, if their numbers are thinned, why won't their numbers quickly rebound after the first spawn to existing densities? Thus the cost, time and efforts were wasted.
My first inclination is to know what the LMB population structure is and manipulate it to better regulate the numbers of tshad. LMB should be feeding primarily on tshad instead of BG and lack of BG might not be due to tshad. Second plan is to find out why the BG are not recruiting since you think there are not enough BG. Make sure the estimate of BG numbers is accurate. As mentioned tshad rarely cause heavy competition toward BG.

The lack of bream may be due to not enough adequate habitat for BG recruitment and not due to too many tshad.

If it was my pond with what I thought had too many shad I would use the money to not poison fish, but instead stock HSB to help reduce shad numbers plus it would add another great predator sport fish that anglers would probably prefer over the LMB. Then if too many tshad were the problem and BG populations improved it would be a win, win, win, win situation - more BG, a 2nd great predator, no wasted money to kll shad if the problem is not too many tshad and no poisoning of at least some non-target fish which will happen.

Greg there are a bunch of studies on your point about BG and TShad. Also a thread here with lots of data.

Here you go.

Here are a couple from this thread -- http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=188082&page=1

Title: The effects of threadfin shad as a forage species for largemouth bass in combination with bluegill, redear, and other forage species


Date: 1976
Abstract: Threadfin shad, Dorosoma petenense (Gunther), were stocked in ponds with an established population of bass, bluegill, and redear and in three ponds containing bass, golden shiners, and fathead minnows. Comparisons of fish populations were made before and after the first successful spawn of shad. The production of bass with bluegill and redear plus shad was essentially the same as with golden shiners and fathead minnows--59.2 pounds per acre and 58.7 pounds per acre, respectively. A significant increase in the growth and condition of bass was seen in the pond stocked with bluegill and redear after the first shad spawn while no change was seen in bass survival.Bluegill and redear recruitment increased significantly after the shad population became established. This apparently was caused by a decreased rate of predation by bass. As a result, the catch per unit of effort of bluegill and redear decreased significantly after the introduction of shad. Bass were in better condition after shad stocking while no change in the condition of bluegill and redear could be detected. In ponds stocked with forage minnows, fathead minnows disappeared the second summer after stocking. An F/C ratio (Forage/Carnivorous) of 2.7 and an A value for bass (percentage of bass over 10 inches in length) of 93.4 was computed for the pond, indicating a bass-crowded condition due to heavy predation on the forage species.From these data, the stocking of shad as additional forage in bass-bluegill-redear ponds cannot be recommended. The stocking of shad with bass and other forage species appears to offer some advantages to bass fishermen if the production of forage species can be increased.


Stocking Threadfin Shad: Consequences for Young-of-Year Fishes

DENNIS R. DEVRIES, ROY A. STEIN, and JEFFREY G. MINER
Ohio Cooperative Fish and Wildlife Research Unit,3 and Department of Zoology The Ohio State University, Columbus, Ohio 43210, USA

GARY G. MITTELBACH
Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan 49060, USA

Abstract

Threadfin shad Dorosoma petenense are commonly introduced into reservoirs to supplement prey available to piscivorous fishes. To determine how early life stages of threadfin shad and their potential competitors and predators interact, we introduced this species into two Ohio lakes—Clark and Stonelick—and evaluated how its young of year influenced young-of-year bluegills Lepomis macrochirus and largemouth bass Micropterus salmoides. After adults were stocked in April, peak abundance of young-of-year threadfin shad occurred in August in both lakes. Bluegills generally spawned earlier than threadfin shad, which apparently reduced competition between young of these species. In Clark Lake, young-of-year threadfin shad did not reduce zooplankton populations, but in Stonelick Lake, peak abundance of young-of-year threadfin shad was followed by a precipitous decline in zooplankton. Data on cladoceran birth rates indicated this decline was due to increased predation by threadfin shad. Survival of bluegills to a size at which they move into the littoral zone also declined in Stonelick Lake, perhaps because of the virtual elimination of zooplankton. Limited survival of bluegills in turn contributed to reduced growth of young-of-year largemouth bass dependent on them as prey. Given that zooplankton declined in one but not the other lake, interactions among young-of-year fishes due to annually introduced threadfin shad will likely vary among systems and years. Nonetheless, introduced threadfin shad could, in some systems in some years, negatively affect growth and recruitment of the very species they were meant to enhance.

Young-of-year threadfin shad, though their abundance peaked in late summer, co-occurred at low densities with limnetic young-of-year bluegills during May through September in Clark Lake. When both species co-occurred in the limnetic zone, they ate only limnetic zooplankton; however, diet overlap values were typically <0.50. Once blue gills moved inshore, the potential for competition with threadfin shad declined greatly.Diets of bluegills collected from the littoral zone did not change between 1987 and 1988 in Clark Lake; all prey types (littoral, limnetic, and cyclopoid copepods) were eaten. Though collected inshore, bluegills apparently moved far enough offshore to consume some limnetic prey, but they ate enough littoral prey to reduce overlap with threadfin shad, which continued to feed entirely on limnetic prey. Consequently, although competition between young-of-year bluegills and young-of-year threadfin shad may occur (particularly during August in Stonelick Lake), the outcome of such interactions in a lake ultimately depends on abundance and species composition of the zooplankton community and on the relative spawning times of the predator fishes. As demonstrated by our results, these factors vary among lakes and years, making generalization difficult.Thus, interactions between limnetic young-ofyear threadfin shad and bluegills may have a pronounced negative effect on young-of-year largemouth bass growth if they lead to reduced survival young-of-year bluegills in the limnetic zone and then to reduced recruitment of bluegills to the littoral zone. Additionally, slower growth may reduce overwinter survival of young-of-year largemouth bass if overwinter survival depends on body size and fat reserves (Adams et al. 1982a, 1982b; reviewed in Adams and DeAngelis 1987). As a consequence, the very management practice intended to enhance the fishery for adult piscivores may reduce survival of the target species. Although these negative effects are not direct (unlike the positive effects of increased prey availability), they could have substantial consequences over several years of such management manipulation


The study with LMB , BG and TShad in ponds stated " Bass were in better condition after shad stocking while no change in the condition of bluegill and redear could be detected.

Yes zooplankton #s were reduced in Stonelick lake but look at the authors conclusions about that :

"Consequently, although competition between young-of-year
bluegills and young-of-year threadfin shad may occur (particularly during August in Stonelick Lake), the outcome of such interactions in a lake ultimately depends on abundance and species composition of the zooplankton community and on the relative spawning times of the predator fishes. As demonstrated by our results, these factors vary among lakes and years, making generalization difficult."

Note that the lake with reduced zooplankton was not a eutrophic pond but a large lake.

Thanks again for the replies. The article linked below pretty well describes our issue. The tshad are grossly overpopulated. If I go out before daylight on a summer morning, like every square yard of the water surface has shad in it. They are far out-competing LMB and BG fry for zooplankton. I do keep the pond well-fertilized. We've had very poor LMB, BG, and RES spawns ever since the shad were introduced.

Back to my original question, should I expect a big project removing shad carcasses or do you guys think it will not be a big issue?

http://fishing.about.com/od/fishfacts/a/shad_2.htm

Thanks.

If you have some machinery that can dig a large hole, you could bury the dead fish on site.

I don't agree with the article wrt TShad. The studies say otherwise. Small impoundments with eutropic waters rarely are overgrazed by tshad. It could be a problem in a few situations but not most.

Good luck with your's and let us know what happens.

Here is Bob's comment to the same question on the noted thread.

Bob Lusk
Editor, Pond Boss Magazine
Lunker


Registered: April 10, 2002
Posts: 2000
Loc: Whitesboro, Texas
(71.96.219.121) Threadfins compete with young bluegill for food. Threadfins prefer zooplankton, as do young bluegill. But, threadfins prefer open water, rather than shoreline cover as bluegill. So, even though they eat similar foods, they don't necessarily eat in the same restaurants. Since they live in a differenct niche, threadfins are an asset. Essentially, the plankton shad eat probably won't be eaten by baby bluegill. So, threadfins don't disrupt bluegill. (There are exceptions, of course...if threadfins populate heavily. But, in that case, there is lots more food for bass anyway.)
In my opinion, threadfins help the bluegill population by reducing competition for food for bass. More forage extrapolates to higher survival of young bluegill, actually enhancing the bluegill population. So, without threadfins, bass tend to decimate bluegill populations. With threadfins, bass are more often satiated and the odds of bluegill survival rise, at least temporarily.
_________________________

I am in Cullman, Alabama, I have a pond that I am renovating / enlarging and would love to come harvest some of your shad... I could bring several guys and boats if neccesary with cast nets and tanks....

Please PM me if you are interested

I would be curious when Mr weathers wrote this article. This was accepted thoughts many years ago. I have a client we just shocked last week. 50 acres unreal load of shad and low bass. He thinks this is due to bass kill in 2010 might be from shad as well as recuirtment is low. I told him this is a great thing. We plan to stock some pure generic bass in the lake we anticipate exceptional growth rates. I recommend you do the same. Give some thought to Bill Cody questions. Good luck.

Pinetar what happened to you I thought we were going to do some shocking for you? Good to see pond is still doing well.