Pond Boss Forums INTRO Questions & Observations TGG Experiment: Summary and Conclusions

On Dec. 3, 2005, I began an experiment to assess 1) the growth, 2) the aggressiveness, and 3) the sustainability of the Georgia Giant (renamed Texas Georgia Giant (TGG by Deb) as offered by Ken’s Fish Hatchery in Georgia. The experiment has now completed just under 18 months and has reached the point where some conclusions can be made. I’ll offer my conclusions up front with subsequent text supporting the conclusions.

Conclusions:
1. Superior growth
2. Superior aggressiveness
3. Not sustainable with HSB as the primary predator

Growth:
• The Data: The primary metric used to assess growth was the ave length of the fish taken from a sample size of 5 with the lowest and highest numbers thrown out and the remaining 3 fish averaged. Twelve such measurements were performed representing 60 fish over the 18 month period. At the 18 month point, the ave. fish came out 9.75 inches.

• My comment: My standard for a nice BG is at least 10 inches. The TGG’s have reached that length very early in their second growing season. In comparable ponds, I have not seen 10 inch CNBG until generally the third growing season. Native 10 inch BG are not often found in my ponds. My conclusion is that the TGG growth is indeed superior to that of other BG in my ponds.

Aggressiveness:
• The Data: The primary metric used to assess aggressiveness was an invented “Aggressiveness Factor” which represented the score of each type of fish during a 10 cast session using the same flies and at virtually the same times. Based on over 200 casts spread over the 18 month period, in all kinds of weather conditions, the TGG consistently scored higher than CNBG and native BG. The TGG proved to be 25% more aggressive than CNBG and 50% more aggressive than native BG.

• My comment: The TGG is a super fun fish to catch on just about any tackle but a 10 inch TGG on a 3 wt fly rod is absolute, pure fun. The TGG does not hit typical poppers (e.g. Miss Prissy), in my pond, but prefers Gambusia imitation flies. The fish can be caught over and over again with very minimal conditioning observed.

Sustainability:
• The Data: This metric, out of necessity, is largely a subjective measure. Trapping and fishing the TGG pond over the 18 month period provided some insight into the sustainability, but at this point it remains an open question. After one year, small Fx offspring began showing up in increasing numbers. Based on trapping results, I concluded that the HSB was a failure as the primary predator. That coupled with the fact that the HSB were completely hook shy made them of no value to me. This spring, when several 5 inch Fx offspring showed up, I decided to “fire” the HSB, remove as many of them as I can, and move to the LMB as the primary predator.

• My comment: I believe that if things were left unchanged, i.e. HSB continued as the predator, the small pond would have become overpopulated with Fx offspring and also have an uncatchable predator in the HSB…both of those items are not acceptable to me. I’m confident that the LMB will solve both problems, but they themselves will also tend toward overpopulation. In order to keep a balance and minimize conditioning, LMB will have to be removed regularly. For me, that does not present a problem, rather a fun situation, but for some that may not be the case. Clearly, in the absence of management and with HSB as the predator, the TGG pond would be overpopulated with Fx offspring by the end of the second growing season.


Before labeling this as just another fish story, please view my website which contains all the data and pictures supporting the experiment.

http://www.meadowlarkponds.com/TGG.htm

ML, did your TGG pond ever clear up, or did it stay murky the whole time?

On a side note, I don't know if we ever really found out whether or not the offspring of the stocker GG's were undesirable or not. It seems that some forum members have seen the next generation GGs get big while remaining identical to the parents.

ML, Have you had the GG in the same pond as tne CNBG? I wonder what the consequences of that would be?

ML, well stated. The TGG were 4-5 inches at stocking correct? It is good you are comparing to your ponds, but we can get CNBG from 4-5 inches to well into 9 inches in less than year, so if we had the same GG growth here it would be disappointg to me. We stocked the same fish in a pond in SC about the sametime and never caught a single fish nor did any showup via electrofishing. Still not sure if predation from lmb, hauling stress or what happened.

ML - Thanks for that great update about your GG experiment. Great work. I am hoping that you can continue some of this data collection for another year or two. It will be very interesting and informative to see how much more the GG will grow each year for the next few years.

ML thanks for all the considerable work you did to document this event in such an outstanding manner. I to hope you will continue to keep doing so for a while as to the GG. So far as I can tell your results are similar to those described in the HBG studies. Do you have an estimate of how old the GG were when they first exhibited spawning behavior or in the alternative spawned and did you see a corresponding slow down in their growth rate at that time?

Thanks for the update ML! As Bill stated, I hope you will continue with the experiment and post periodic updates.

Thanks, ML.

I hope you continue to get those nice photos over the next two or three years. It will be interesting to see what sort of maximum sizes that you see.

Sunil,

No, it stayed murky the entire time. Regarding the offspring, I think a lot depends on the numbers, i.e. very high numbers of fish, relatively small size and conversly. From this point forward in this pond, all offspring will be removed and my efforts will be directed at growing the original remaining fish to the largest size that they can attain.

Howard,

No, certainly not intentionally at least. Three weeks ago, while fishing with my grandson, we caught what looked distinctly like a CNBG from the TGG pond. I have no idea how that fish got in the TGG pond. It was about 6 inches and fat and had the beginnings of the copper bar across the nose. Nature finds a way.

Regarding consequences, the strategy in this pond stocking was to grow out the target fish, the original stockers, to whatever size they could attain. GG's are reportedly about 70% male, unlike regular HBG which are reportedly about 90% male. Adding GG's to a pond with CNBG or adding CNBG with the initial stocking would simply introduce more of the "undesirable" Fx offspring....more females to breed and cross breed. I say undesirable because in this case the target fish are the original stockers and all other fish detract from the growth of those target fish. Most people that sell HBG and/or GG's all recommend that they not be stocked with other BG for that reason.

I haven't seen it in writing anywhere, but presumably the offspring of the GG and HBG have a more normal distribution of sex, i.e. more females and closer to 50/50 ratio. Regardless, the population of fish in the pond is certainly best controlled by minimizing the number of surviving offspring and not adding to the female breeding pool.

Greg,

Yes, 4-5's. My comments on the growth are based strictly on my experience in my ponds which I recognize is limited in comparison to yours, not to mention geographical differences.

I have observed one interesting thing about the TGG growth...it seems to be much more uniform than the growth of regular BG. If I had kept the measurements on all fish over the entire period and computed a mean and standard deviation on the variation in length at each measurement point, I believe the standard deviation would have been significantly smaller than a comparable population of regular BG. Looking back, I kind of wish I had done those statistics, but then there probably wouldn't be any comparative data anyhow. Have you observed anything similar?

I wonder if the murky water curtailed the HSB's ability to eat the GG offspring. If so, I wonder if the LMB could do any better.

Bill,

I sincerely appreciate your kind words very much. You know better than anyone the effort required to conduct this type of thing. It is probably even more difficult for a rookie like me because I wanted to do the best possible job I could to accurately portray the results for all those who have followed this little experiment...anything less would have been unacceptable.

Regarding the continuation of the expeiment and requests from you and others for continued pictures, my plan is to continue with this pond and these 200 fish for many years into the future. I want to see for myself what the eventual growth of these fish turns out to be. However, my bi-monthly data collection is over as are the regular posts on the experiments' status.

I will continue to update my web site with pictures and special data as appropriate and encourage everyone who has any interest in these fish to just jump on over to the site and check it out. I'd be most happy to address any comments you or anyone else has regarding the continued experiment or anything else on my web site...the web site is simply my way of documenting my journey with ponds and the creatures that inhabit them. Thanks.

Sunil, I think LMB will be better predators of sunfishes compared to HSB in murky water. LMB will also be better predators in shallow water and in cluttered (structure) habitats compared to HSB. When feed treained HSB have pellet food available I think they will utilize that as a primary food source compared to fish hunting. You can't beat the LMB when it comes to eating sunfish. LMB have evolved to prey on sunfishes.

EWEST, I'm guessing here but I believe spawning happened last June and July following the prior Dec. stocking. Interestingly, the data sheets show no growth during that time. The offspring started showing up in Sept. in the traps and I began catching some small fish on flies along about Dec. When several of about 5 inches showed up in spring, I made the decision to change predators.

What if...

Your water wasn't overly murky.

There was minimal structure.

You didn't feed pellets or maybe 1/4 the typical amount.

Would that get you closer to a workable GG HSB pond? I'm thinking about options for my 1/2 - 3/4 acre future pond. I'm patient enough to accept a slower rate of growth if stunting isn't the finale result.

GW,

I'll give you my opinion, FWIW...

Artificial feeding is a very key factor in your success or failure w/HSB in the situation you describe. I've done a bunch of stomach autopsies recently on HSB taken from my largest pond...a pond stuffed full of small forage perfectly suited for the mouth of a HSB...and not a single HSB had anything but pellets in the stomach. Nothing but pellets.

In my TGG pond, I have artificially fed very little but every time I have fed the HSB are the first to line up at the trough.

My opinion is that if you stock Gambusia as recommended and maintain a good grass/weed shoreline for them, you will more than adequately meet the feeding needs of your GG's. Throw in a few Tilapia the second year and the GG's will really take off....at least that is what I am expecting in my second year. Artificial feeding will only further detract from the HSB's limitations as a small pond predator.

Meadowlark, if there's no (or little) pelleted food, won't the HSB be forced to prey on small GG?

Yes. I would think so. By the way, I'd like to amplify a little on the question of GG offspring and how many is too many....

If you don't mind catching 5 inch fish and only occasionally catching the larger 10 inchers, I'd guess the HSB in the situation you describe will work just fine. Myself, I have no interest or desire to catch 5 inch fish of any type on a regular basis and hence my tolerance for them is probably more stringent than some. If you like the small fish, I think you will be successful with the HSB. If you really want to grow out some big BG, then you want to minimize (zero), the number of surviving small fish...no matter what type of BG they are.

ML, you are correct the CNBG probably do have varioabel growth. I wish I had the time to do a more controlled experiment like yours. I also wish the GG woudl made it in SC so I can give an update on those, oh well. Client might try them again.

One other thing, with clients wanting to grow bass but have some GG we do sotck CNBG b/c otherwise they would be little forage avail to bass in the early stages. In this case we have done something like 600 CNBG, 200 RES and 100 GG. We have noticed some fish with green sunfish type char. However in this manner the CNBG outnumber (higher fecundity, etc.) and phase out the green influence that I do not desire and they still have some good original GG to catch.