Pond Boss Forums INTRO Questions & Observations Where I am Today with my lakes...ISSUES

And several largemouth bass.

As far as Preditors go, what would be ideal would be to have Bass and Catfish at the top of the food chain and just cull their numbers....I think the picture is a flathead. I would rather have Blues and channels and tiger Bass. Right now I think and I say "THink" I am bass heavy. So I want to slot on limmit on the bas everything under 12 inches. The catfish are eating the feed but they have slowed down some what. I am slotting on thoes as well, everything under 13 inches with them, but this is Channels now not blues.
Some how my blues are not as big as my channels. Infact sort of worried about them to a degree, I think they are doing worse than the three. Hence more reason to stock better forage.

So when we talk about the Goals they are the same wheather its trophy Bass or trophy catfish. The key besides good forage base is keeping the number of mouths to feed down!!
I think for a 10 acre lake, 150 Channels and 150 blue cats and maybe about 500 Large mouth bass..

I went back and looked at the studies and several more on the subject. The methods and data are sound and involved at least 20 professional top notch FS writing in peer reviewed method. The Nutt article (not a study) is based on those and is clear about its purpose “trophy LMB”. You can state your opinion. You can not make statements like "I personally feel that the studies that try to claim that TS or gizzard shad either one do not affect bluegill size, are at the very best poorly substantiated and researched with shoddy methods and conclusions, and at worst just skewed science." , questioning the ability and ethics of a number of professionally trained Fisheries Scientists. I don’t think Bob wants defamatory statements placed on the forum.

Here is the info so others can read it and make their own choice.

Walt have you read the studies not the abstracts ? I have seen shad added to many lakes/ponds with all different outcomes. I have read many studies on the subject both as to GShad and Tshad. Generalizations are suspect. I have added below some text which should show the uncertainty and differences. From these I gather that GShad are a problem unless you want and have big LMB as noted above. TShad are not the same as they often don't compete significantly with BG and don't suppress the recruitment of LMB and BG like GShad. Even in the GShad studies it is not so much the competition for food as it is reduced predation on BG and other factors. The last study below is an examination of some 60 prior studies on GShad and TShad as forage .



Direct and indirect effects of gizzard shad on bluegill growth and population size structure
"These results demonstrate that the presence of gizzard shad is associated with reduced bluegill growth rates and adult size structure and that mechanisms other than direct competition for food resources may be responsible"


Effects of Waterbody Type and Management Actions on Bluegill Growth Rates
"Managers should recognize basic differences in growth patterns between water body types when determining which management actions should be implemented or when evaluating their success."

The Influence of Gizzard Shad (Dorosoma clpedianum) on Plankton Community Dynamics in Earthen Ponds


Date: 1995
Abstract: The impacts of gizzard shad on plankton community interrelationships were evaluated in six, 2 to 5 ha ponds over a 3-year period. All ponds were stocked with largemouth bass (Micropterus salmoides) and sunfish (Lepomis spp.). Three of the six ponds were stocked with gizzard shad at random while the other three served as controls. The zooplankton and phytoplankton were sampled and analyzed three times during 1992 (before shad introduction) and twice a month during the growing seasons of 1993 and 1994. Water quality variables were measured once in 1992 and every other month during the growing seasons of 1993 and 1994. Phytoplankton primary productivity was measured three times in 1992 before the introduction of shad and once a month during the growing seasons of 1993 and 1994. Zooplankton density, biomass and size were affected by gizzard shad during summer, 1993 and spring and fall of 1994. Statistical differences between treatments occurred in spring, 1994 (p<0.13) with higher density, higher biomass, and smaller organisms in the shad treatment. Phytoplankton density, diversity and primary productivity were all higher in the shad treatments (p<0.13) during fall, 1994. Shad influenced the plankton community in a web-like fashion directly impacting zooplankton and phytoplankton simultaneously and indirectly affecting phytoplankton by altering the zooplankton. Shad shifted phytoplankton size structure by first reducing large phytoplankton (>70 mm) in the shad treatment immediately after shad introduction in 1993 and enhancing small phytoplankton (C28 mm) a year after shad introduction (1994). Through this size structuring, shad increased the photosynthetic efficiency of the phytoplankton community to twice that of ponds without shad by summer, 1994 (p =0.067) and increased primary productivity to 1.5 times that of ponds without shad by fall, 1994 (p =0.098).



Relationships between trophic state and gizzard shad, bluegill sunfish, and largemouth bass populations in three Alabama impoundments


Date: 1989
Abstract: Three Alabama impoundments were studied to analyze the relationship between fertility levels and the population and community structures of several species of fish. Chlorophyll a concentrations were used to classify lake trophic status. Fish communities and populations were similar in structure between the two eutrophic systems and differed from the oligotrophic system. Eutrophic systems were shown to have a higher relative abundance of prey species, in particular gizzard shad. Overall production was lower in the oligotrophic systems. Community structure in the eutrophic systems reflected a greater influence of gizzard shad. Bluegill abundance doubled while gizzard shad numbers increased twentyfive-fold. Largemouth bass increased eight times in number. Prey populations were overcrowded, characterized by slow growth, poor condition, and reduced spawning, due to the high relative abundance of gizzard shad. Predator populations showed low recruitment and poor condition in smaller fish due to lack of suitable size prey.The relative abundance of predator species increased in the oligotrophic system. Bluegill were in better condition and had better distribution across size classes. Young of year and age one gizzard shad were absent from sampling throughout the year.



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


Manipulating Shad to Enhance Sport Fisheries

in North America: An Assessment

DENNIS R. DEVRIES' AND ROY A. STEIN

Manipulating forage fish populations to enhance sport fisheries is a common management practice. Here we review the literature dealing with manipulations of gizzard shad Dorosoma cepedianum and threadfin shad D. petenense to assess whether or not this practice has been successful. Shad introduction has tended to enhance predators, such as white crappie Pomoxis annularis, black crappie P. nigromaculatus, and largemouth bass Micropterus salmoides, and negatively affect presumed competitors, such as bluegill Lepomis macrochirus. However, responses have not been consistent within a species: some studies document negative responses of predators or positive responses of competitors to shad introduction. Depending on the study, target species have experienced negative, neutral, and positive effects due to shad removal, making generalizations impossible. We were not able to generalize about how shad influence sport fishes. Although bluegill appeared to be more negatively affected by shad than crappies, the response of largemouth bass being intermediate between the two, we cannot draw definite conclusions because the entire range of results occurred for each target species.


The chart tells the story - in half of the 12 studies addressing the effect on BG by shad 6 were positive to neutral and 6 were negative to neutral. But more important are the statements that blanket generalizations were not possible.






The results presented here indicate that several aspects of whole systems must be quantified if we are to assess how forage-fish manipulations affect a fish community. Based on our review of manipulations involving gizzard and threadfin shad, potential competition and predation, spatial refuges, indirect effects through common predators and prey, and the influence of ontogenetic shifts in habitat and diet of the target and introduced species are all critical to being able to predict the influence of a forage-fish manipulation on a target species.
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Here is the original discussion thread on the K Nutt article in PB.

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=11350&fpart=1

Here is a later discussion.

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=159008&fpart=1


Walt you made my point. It depends on the pond. The chart tells the story - in half of the 12 studies addressing the effect on BG by shad 6 were positive to neutral and 6 were negative to neutral. But more important are the statements that blanket generalizations were not possible.

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. I can only find the links to the 2 Abstracts but I have those studies elsewhere.

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."

I have stayed out of this discussion since Big-Pond is a client and can get my two cents via email or phone. Just ask him about our fun looking for a lost wallet when he came by to get some used feeders. The lack of bass growth is due to the factors he described. We have not shocked the lake but based on conversations I do think it bass heavy. Yes his brother has some awesome lakes in SW, GA and thanks to Big Pond did all the stocking on those.

Now on the TShad discussion. I love reading these studies and glad they have been done, so thanks ewest and walt. Please do not think this is being arrogant or boastful that is not the intent (yall know me). However we shock about 100 lakes a year. I would say about 20-30 of those have threadfin shad. I think this gives us cred on what effect tshad have on bluegill.

So what do we see? Well as you know every situation is different. However in 9/10 cases the bluegill population of 3”-6” bluegill is higher than in the past prior to threadfin shad introductions. Also the average size bluegill is not as large. Those are the facts. My opinion is a simple one as threadfin populations increase this allows more bluegill to survive (due to less predation pressure). This creates increased competition amongest bluegill and lower bluegill growth. Of course we see the same happen with high bass harvest as well leading to more bluegill and smaller sizes.

As always it is about goals…I told big pond in an email if you want big bluegill do not stock if you want big bass (big cats) I think establishment is a good thing. Am I missing something here? FYI we get good establishment when fertile on 10 acre pond with just one load and our load is two 100 gallon tanks full of fish 4500 >1.5 inches stocked right when ready to spawn.

There is no doubt thaty I need to get some Tshad in the big lake. From what I am learning from the Blue cats and their growth rates, I am WAY behind on mine for sure....I could be that I have bad genetics in my fish...I am just not sure. But there are people getting AMAZING growth rates out of their fish in a ver short amount of time... I have to get Greg to get me some Shad this spring..

Thanks Greg and no you are not missing anything and are on point. The answer is it depends as noted in the study that reviewed the outcome of 60 other studies on shad effects (see chart above). The point is that no generlizations can be safely made. They are niteher right nor wrong in every situation. As a result blanket recommendations to use or never use TShad are inappropriate as it depends on the goal and the pond. Here is what Bob said on another 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.
_________________________
My mom told me, "If it ain't one thing, it's another"...she was right.


Sounds a lot like your answer Greg. This was for a balanced pond not trophy LMB or BG. Good luck Big Pond and post pics of those tiger bass and cats.

Keep this subject rolling its good stuff...Rememebr Good Blue cat water is the same as Good Large Mouth Bass water...they are one in the same...

Greetings, fellas!
Thought I might enter this discussion for a moment. Part of the way I make a living is growing huge bass for clients. It's not an easy thing to do, or many people would do it.
Walt and Eric addressed research studies, so I'll be more colloquial and let you know some real world stories of situations that have happened with my lake management business.
There are some consistencies though.
Here's my first statement. Every trophy bass lake I manage, that grows good numbers of double-digit bass, has gizzard shad. Every one.
Second, if we don't have threadfins, we stock them.
Third, each of these lakes has giant bluegll and none have seen an overall decrease in bluegill sizes. But, I do see an increase in numbers of mid-sized bluegill, especially 3-4 inchers.
Here's what happens.
I start a lake with bluegill, redear sunfish and fathead minnows to establish a food chain. Then, after enough time to establish these fish, I stock bass at 50 per surface acre. I think the best way to stock bass is to stock small fingerlings and mix the gene pool. Personally, I like to stock half Floridas and half natives, but I will go 1/3 Florida, 1/3 Natives and 1/3 F1 crosses.
I allow this fishery to develop. Oftentimes, we'll feed the bluegill with Aquamax to expedite the process of establishing several size classes of bluegill.
As bass grow, we monitor their growth rates, either by hook and line or electrofishing or both. I usually won't electrofish until the third year, however, to leave the fish alone.
Job One is to get bass to 16.5 inches long as soon as possible. That's a hard job, especially since these critters start reproducing at 9-10" long, sometimes at the beginning of their second year.
In the second year, we stock threadfins...when they are available and as long as the lake has a good chance for the fish to survive most winters. In Texas and parts of the south, threadfins will live 4 of 5 winters. Draw an east-west line through Oklahoma City and south of that line threadfins will live 2-3 out of 5 winters, depending how far south of that line the lake is.
Once we can consistently quantify that at least 25% (by head count) of the bass we collect via electrofishing are 16.5 inches long or larger, I'll stock gizzard shad.
Keep in mind, my mission has not been to grow huge bluegill with these lakes. The mission has been to grow huge bass.
My thinking has been that once a bass grows to 16.5 inches in length, its feeding habits change dramatically. Up to that point, these bass depend primarily on small fish, especially young of the year bluegill and similar size creatures. But, a 16.5 inch bass' mouth can reach around a 9-10" bass. That's what they begin to feed on. Enter gizzard shad. These growing bass now have the chance to quickly grow to 18, 19, 20 inches in length. The larger they become, the larger the meals they eat, less often.
While I won't dispute that shad compete with bluegill for food, I will offer that this does not have a negative impact on bluegill. I'll tell you quite the contrary. As the bass population increases in biomass and the size classes are fairly distributed, so are the bluegill size classes, although I also see an increase in 3-4" bluegill numbers. This "balanced" system is pretty much dictated by the dynamics of the predator base. In well managed trophy bass lakes, there are different size ranges of bass feeding in different niches of the food chain and they effectively control numbers of bluegill. The consequences...every time...is that we always grow some huge bluegill, often pushing two pounds. Big bass eat big bluegill, helping thin their numbers, resulting in fewer large bluegill which grow exceptionally fast and quite large.
What I see with shad, both species, is that their populations ebb and flow, feast or famine. During late summer, early fall, we'll see tens of thousands of shad but by winter, their numbers have diminished. Bluegill ebb and flow more often and their numbers rise and fall more consistently that the shad.
I electrofished a lake this week...a 30 acre lake I have helped off and on for 25 years. At first, this lake was overloaded with overcrowded bass and very little food. Through a harvest program, taking bass, and stocking bluegill adults, the lake reversed. Over time, the club worked hard to manage the dynamics of the fishery and here's what I saw Tuesday.
Keep in mind their mission is to have a balanced fish and they don't care too much about growing many giant bass.
We observed 5 size classes of gizzard shad (no one will own up to stocking them) and the majority were this year's hatch, fish about 3-4 inches long. We collected 5 size classes of bass (125 fish) and Wr's were right at 100, some a little higher, but not much. We collected 6 size classes of bluegill, 3 of those classes from this year, with several bluegill at least 10 inches long. We also collected 3 size classes of redear sunfish and 3 size classes of black crappie. By far, the largest biomass was gizzard shad. At the same time, there is very little structure/cover for those species of fish which need it.
Bottom line, we saw good numbers of bluegill larger than 7" and quite a few true trophies.
The majority of the bass were well beyond 16 inches, but we did see this year's class (which we normally don't, when the bass are overcrowded) as well as plenty of last year's bass hatch. This lake is neither fertilized nor fed any supplemental feed.
Another lake, 120 acres east of Athens, Texas, was electrofished two weeks ago. If we saw one school of young of the year threadfins, we saw 250, rippling the mirror-flat water just before dark. Each school had 750-2,000 fish in it. That's lots of baby threadfins. When we cranked up the electrofishing boat, we saw tens of thousands of these creatures, along with several schools of gizzard shad, too. Bass are thriving, but so are the bluegill. We collected several bluegill in the 1 3/4 pound size range and observed hundreds smaller fish.
So, my experiences suggest that while shad may compete with bluegill for food, the other dynamics of the fishery overcome that competition in healthy ways.
I do believe, however, that this lake has so many huge bluegill in part due to the fact we supplementally feed them Aquamax pellets for the purpose of increasing their sizes and numbers. This client DOES want to grow some huge bass, which we are doing. One other note about this lake...in the past we have stocked tilapia, but this year chose not to simply because there were so many shad going into the growing season and the bluegill were numerous, too. So far, it looks like a good decision.
I could cite more stories, all similar, but I gotta go make a living.
But, I thought it proper to share my perspective.

Holy Moly Mr. Lusk. Have you ever thought about writing a book on the subject of raising trophy bass or pond management? Perhaps even a magazine, you could start off small, just a few pages, no color or anything fancy but over time you could build this magazine. You know, get some advertisers and once your subscription base increases you could add some color photos and increase the page count. Heck who knows, maybe even one day the magazine would would be sold in Bass Pro Shops.

Heck you might even be able to start a consulting business and help people manage their ponds. Oh, and how about a fish farm, yea you could start a fish farm and raise fish to sell to other people.

On second thought never mind, that sounds like way, way too much work.

What a novel idea! Maybe I can squeeze something in between all the parties and fishing expeditions...

Bob points out in real terms what the studies (over 60) show and what Bill (it all depends) and others (including me) preach. Ponds and lakes are dynamic systems with many factors in play. Look at the ecosystem as a whole over time. Water quality , food , plants/plankton , different species and their interactions , potential competition and predation, spatial refuges/cover & habitat, direct and indirect effects through common predators and prey, and the influence of ontogenetic shifts in habitat and diet of the target and introduced species are all critical. These factors vary in large amounts among ponds and lakes and between years, making generalization difficult. I suggest a look back to Mark Cornwell’s recent PB mag article on the food web components and its complexity . These complexities are now interpreted using concepts like trophic cascades, … behavioral response to predation risk … , changes in behavior and reproductive strategies , and balancing between multiple stable states where the desired “balanced” state represents an unstable cusp between 2 undesirable stable states (stunted predator or prey populations with low body condition). You will see these concepts again in the next PB mag in an article on unintended consequences.

The names may be new but the concepts you know. The concept of a trophic cascade - that predators reduce the abundance of herbivores, allowing plants to flourish which focuses on the role of top-down forces (eg predation) and indirect effects in shaping ecological communities vs. trophodynamics, which explains the structure of communities using only bottom-up forces (eg resource limitation). IMO both are at work and must be understood as part of the whole ecosystem approach.

Would there be any long-term risk in introducing TFS into a LMB/HSB/CNBG pond if your pond's geographical location is such that the TFS will die off every 4-5 years? If BG size is important to your goals and the TFS appear to be reducing the larger BG, wouldn't die-off take care of the problem. So, would GSH potentially cause a similar situation without the benefit of die-offs? Does that make TFS a "better" fusiform prey than GSH for growing big LMB. I intend to add one or the other to my pond next year..I think...du

david u let’s try to work through this based on the post I made at the same time as yours (1:57).

Can you provide basic system info ?

Lake size , size of existing fish , number and condition of fish , feeding or not , expected fishing pressure (fish harvested), plankton bloom and visibility depth , location , and most importantly your goals (trophy LMB . balanced or trophy BG). I will provide that GShiners and TShad are different and don’t effect the system the same. Also I will state that 1 of ours has that situation (LMB , BG , HSB , RES and TShad) and another is close but new.