Pond Boss Forums MANAGING AN EXISTING POND Corrective stocking Green Sunfish vs Bluegill

Dave Davidson said: "I'm not an expert on anything."

Not true!!!

You've got being a Texas hick down cold!!!!

Ouch!

Yep, and getting better every day.

Jim, I'm glad you came back.. I enjoyed readying your previous posts.

I need to look back to see if they reared fish in ponds or not. That makes a huge difference. In a pond setting, as stock density increases relative to what the forage base provides, the feed quality becomes more important as you approach the feedlot state. At low stocking densities you can have feed being more impactful by simply improving productivity and quality of forage base.

I wish I could get good results with BG as I do with CC using the same feed. I can buy 50 pounds of 32% CC pellets for $22 including taxes, whereas 40 pounds of Optimal BG costs $50. Likely the Optimal would have better results for BG, but about half of it would get consumed by CC before the BG get to it. I don't know if results for CC would be much better with Optimal BG than with 32% CC pellets.

You know I love you, Guvnor!!!

We use what call feeding cylinders to keep grass carp from eating feed intended for Bluegill that might keep most of you catfish out. It is a modification of a feed ring. Screened lid might, I say might, increase value of the feeding structure for the fish as it protects from overhead predators (@#$%!$#@% herons).

If interested I will see about posting an image and better description of design. Setup does not help control competitiveness of Green Sunfish.

Back to the GSF. When the GSF and BG come together, like in many of the ponds represented in this thread. Jim in your experience and observiation, do the GSF or BG traits dominate? I'm guessing you see hybrid vigor through the first gen. I have read that the GSF traits dominate and over time the HBG look more like GSF than a BG. Can the cross go both ways...male GSF X female BG or male BG x female GSF? If not why? Also I have read that the majority of HBG are male...what causes this? They are not sterile like a mule or do you see that??

Sorry if I'm asking to many questions but when they pop in my head they don't leave until I ask...yeah I was that kid in school. lol

To my eye the F1 hybrid is intermediate. Never played with direction much on that one but to my understanding it will go either way naturally if female of a either species is having a hard time finding a conspecific mate. The hybrid does feed more aggressively but in my food-fish setting the pure Bluegill outperforms the hybrid and pure Green.

Hybrid Green x Bluegill do have reduced reproductive output but possibly for more reasons than simply fertility. Reduced fertility is low when hybrid bred to hybrid due to aneuploidy (look it up) but not as bad when backcrossed to either parental species of even a third to make a trihybrid. Mismatch of behaviors is what I see to be a real problem for the male hybrid where they put nest close together like Bluegill but defend larger area like a Green. This can be a real problem when defending nest bound brood. I suggested that to Roy Heidinger when I was a student but I do not think he gave it much credit. The more I have watched the more confident that mechanism also operates. Behavior of hybrid fry and fingerlings may not be good for avoiding predators like LMB. If you get the chance, try to observe how a Bluegill vs Green Sunfish behave when threatened by a LMB. They differ.

Sex determination mechanism not well worked out. Look for a paper by Wang on the subject. I will assert based on over a hundred broods where we tracked sex ratio that it is genetically based on not like mammals or birds and it involves either multiple loci or alleles. Matings between individual Bluegill can give skewed sex ratios that rival that of hybrids. Skewed can be strong or weak and towards either male or female. Somehow males promoted by heterozygosity and hybrids really push that.

Green x Bluegill are not sterile as indicated above. There are some hybrids that are dead sterile (no fertility) or only one sex is fertile. More funky stuff we have seen where viability is strongly impacted by direction of cross.

More could be said about sex ratios but that would require a sit down.

As per wikipedia.

Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes, which is called euploidy.

I think I found the abstract of the article you were talking about...for everyone interested.

There is increasing evidence that temperature effects on sex ratio in fish species are ubiquitous. Temperature effects on sex ratio could be influenced by parent, strain, and population, whether in fish species with temperature-dependent sex determination or genetic sex determination plus temperature effects. In the present study, effects of genotype-temperature interactions on sex determination in bluegill sunfish were further investigated, based on our previous results, using four geographic strains: Hebron, Jones, Hocking, and Missouri. In the Hebron strain, the two higher-temperature treatment groups (24 °C and 32 °C) produced more males than the low-temperature treatment group (17 °C) from 6 days post-hatching (dph) to 90 dph. In contrast, the low-temperature treatment produced more males than the other two higher-temperature treatments in the Jones strain. No significant effects of temperature on sex ratio were detected in the other two strains. Our results from sex ratio variance in different treatment times suggest that the thermosensitive period of sex differentiation occurs prior to 40 dph. Our results further confirmed that genotype-temperature interactions influence sex determination in bluegill. Therefore, to significantly increase the proportion of males, which grow faster and larger than females, a consumer- and environment-friendly approach may be achieved through selection of temperature sensitivity in bluegill.

Zhi-Gang Shen, Han-Ping Wang,* Hong Yao, Paul O’Bryant, Dean Rapp, and Kun-Qian Zhu
Aquaculture Genetics and Breeding Laboratory, The Ohio State University South Centers, 1864 Shyville Road, Piketon, Ohio, 45661

Chromosome number among the larger sunfishes is conserved. Problem is loci distributions are not. During gamete formation the mismating can break some chromosomes and make others larger. Net effect is so copies of loci lost or gained and in a hybrid that can be accompanied by big chunks of chromosomes. Some of the changes are fusions of chromosomes, splitting of chromosomes, additions and outright losses.

Jim, you said the GSF and HBG both have an increased area they protect compared to a BG. Does that mean that the nest itself will be larger in size? I have noticed that I have some fairly large nests compared to the rest. Some even look like the nests may combine. Do they clean the area they protect or the clean area is just for the brood?

Thanks for putting up with all my questions!!

That's it.

@peachtree.


You know you were already biting off a lot when managing just the BG versus GSF interaction. Now you are really complicating the whole mess by overthinking it. This other stuff will not relevant unless you do something to promote barnyard folly action.

Maybe you should rotenone or drain pond to start over. You will sleep better.

Here are a few more Wang studies. There are some great articles by Neff on the subject where they did extensive diving and observation over years, there are also great genetic articles on Centrarchidae genetics by Bolnick and Near - TEMPO OF HYBRID INVIABILITY IN CENTRARCHID FISHES (TELEOSTEI: CENTRARCHIDAE), plus much more.

Inherent Growth Capacity and Social Costs of Bluegill and Hybrids of Bluegill and Green Sunfish: Which Fish Really Grows Faster?
R. S. Hayward & H. P. Wang
Abstract
There is interest in knowing whether the bluegill Lepomis macrochirus or a hybrid of bluegill and green sunfish L. cyanellus (F1: male bluegill × female green sunfish; hereafter called B × G hybrids) can be grown faster to food market size (225–340 g). The predominant view is that the hybrid grows faster. In this study, the inherent growth capacities (IGCs) of age-1 bluegills and B × G hybrids were determined over four successive 25-d periods (May–August 2000) by holding them individually at 22°C and feeding them to apparent satiation three times daily. The hybrid's IGC was greater during period 1 but fell to only 33% of the bluegill's over the three subsequent periods; the consumption and gross growth efficiency (GGE) of the hybrid showed similar declining patterns. The growth-in-weight trajectory of bluegills crossed above that of the hybrids at about 30 g. Gonadosomatic index values suggested that hybrid growth rates declined below those of the bluegill because the former invested more energy in gonads as age-1 fish. A follow-up study, conducted under similar conditions from August 2000 to March 2001, found that individually held age-1 bluegills starting at 30 g reached more than 100 g in 200 d, gaining nearly twice the weight achieved by hybrids of similar starting weight that were reared in parallel. The costs of social interaction in terms of reduced consumption, growth, and GGE were also quantified for bluegills and hybrids by comparing individually held fish with group-held fish over periods 1–3. Social costs reduced the growth rates of grouped bluegills more than those of grouped hybrids over the 75-d period. Our findings indicate that while the IGC was higher for the hybrids as early age-1 fish, the long-term IGC (e.g., to food market weights) is higher for bluegills; however, this result may be obscured, in part, by the bluegill's higher social costs. Reduction of bluegill social costs in certain culture settings should result in growth rates that approach their higher IGC. Also, social costs varied in response to short-term shifts in the IGCs of both fishes, indicating a previously unknown influence on social interactions in fishes.

Use of Compensatory Growth to Double Hybrid Sunfish Growth Rates
Robert S. Hayward , Douglas B. Noltie & Ning Wang

Abstract
We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid sunfish (F1 hybrid of female green sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained/weight of all fish consumed) did not differ among the control and treatment groups over full experimental periods; however, GGE was higher than controls during some refeeding periods in group D14 (i.e., when CG was active). Findings show that the CG response can be exploited in some fishes to cause them to substantially outgrow conspecifics that are fed every day without restriction, with no loss of growth efficiency. Our use of hyperphagia to gauge durations of refeeding periods was critical to achieving growth improvements through CG.

A new approach to quantifying morphological variation in bluegill Lepomis macrochirus
Authors S. P. Gerry, J. Wang,D. J. Ellerby

Abstract
Bluegill Lepomis macrochirus showed intraspecific morphological and behavioural differences dependent on the environment. Pelagic L. macrochirus had more fusiform bodies, a higher pectoral fin aspect ratio, a larger spiny dorsal fin area and pectoral fins located farther from the centre of mass than littoral L. macrochirus (P < 0·05). The shape of the body and pectoral fins, in particular, were suggestive of adaptation for sustained high-speed and economical labriform swimming. Littoral L. macrochirus had a deeper and wider body, deeper caudal fins and wider mouths than pelagic L. macrochirus (P < 0·05). Additionally, the soft dorsal, pelvic, anal and caudal fins of littoral L. macrochirus were positioned farther from the centre of mass (P < 0·05). The size and placement of these fins suggested that they will be effective in creating turning moments to facilitate manoeuvring in the macrophyte-dense littoral habitat.


Group holding impedes compensatory growth of hybrid sunfish
. Robert S Hayward e Ning Wang. Douglas B Noltie

Abstract
An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid sunfish (F1: female green sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.

I hear ya. No I sleep fine. lol. Since I decided the GSF are okay its all good. Just trying to learn now. Before pond boss I was one of those call everything sunfish a "perch" guys. Never knew a GSF existed. I guess I'm just trying to understand them, their habits and such. I was an agriculture teacher (FFA) for ten years, taught animal science, plant science, and such , now teach welding at a small community college and am a diesel mechanic for my father in law. I just love to learn. Thanks for putting up with me.

Thanks ewest for posting those articles. Never knew such existed. The more I study this, the more I figure out I have been missing out and misunderstanding ponds and fish for so many years.

Double check your Wang's as not all Wang's are equal.


I am not fan of the compensatory growth concept. We have not been able to repeat it at growth rates that are likely essential for commercial production. I remember back in 1990's when that was coming out. Growth we had with hybrid Bluegill that we thought were poor were better than that where compensatory growth comes into play.

As you know there is a ton of info out there . Way more than the affiliated Wangs. There is some great stuff available the problem is sorting out all the noise. More to follow. Compensatory growth is interesting as a concept but not real applicable to supplemental feeding.

WRT BG and HBG most folks want a direct comparison but the real comparison is single sex male BG to HBG due to sex % in HBG. Studies support this comparison. See Wang # 1 above for example.

To do the BG versus HBG properly, they need to have the same father and potentially the same spawn date. Then have three or more half sibling families that are reared under very consistent conditions such as the same RAS. You can do that pretty easily using pre-made nests if you can get females to ripen on same day. It does not take much to get females to synchronize as it seems to be their natural way. Then grow out broods to point where the can be tagged and if need be females removed or at least equalized across broods. We priced out such an effort but could not find a way to fund it. Doing it in a RAS may not give same results as ponds

What does WRT stand for?

With respect to - common blog/email lingo.

Jim, I'm enjoying reading your posts. My problem, and I suspect the problem of other members also, lies in figuring out how to ratchet down your level of intensity to something approachable, applicable, and manageable in a backyard farm pond.

I'm sure there's a goldmine of info in there, I just need to figure out how to peel off a couple tough, outer layers of commercial aquaculture in order to get down to the delicious, tender pondmeister center.