Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Trying to control excess GSF

Your attempt to manage the pond will be greatly facilitated by your presence here.

Every pond's best friend is a manager who cares to collect information in a scientific manner. You're doin' good buddy.

So Bruce, am I on the right track by adding the LMB and CC?

I'm not really the "big guy" when it comes to GS control. I think Theo, ewest, Bill Cody, DIED, Dave Davidson, Dave Willis and others are more qualified. Personally, I would add the LMB and go easy on the CC, but that's mostly because the guys whose ponds I manage almost always regret having more CC. I love big panfish, so I like high density predators like LMB.

Bruce what type fish are you showing? He does look like he has a tad bit of a attitude!

Everything I know about GSF control I know from reading, mostly Bob Lusk. Crowd the bass to beat down the GSF numbers, then introduce good BG stock for forage and throttle back on the bass numbers some. IIRC it's usually a 3-4 year process.

Like Bruce said, a lot of us have more BIG CC than we want. If they will be fed, decide how many CC you want to harvest over a two-three year period. Then stock half that number.

Thats good to know. Last fall the DNR added 150 bass, then I added 300. I should start seeing a decline in some of the BG population this spring. Can green sunfish come from crossing HBG and BG?

Its supposed to get up to almost 70 this week, I may take a vacation day and go do a little fishing.

GSF can not come from crossing BG and HBG. There is even a question if HBG can backcross with either parent species. IMO best guess is they can backcross. GSF are a species and BG are a species and HBG are a cross between the two. Over time certain traits (good or bad) can become more predominate through outbreeding depression or hybrid vigor. Over very long periods of time a distinct population can change so that its traits are closer to GSF or BG.

Someone tell me how the pond is overrun with pure GSF when the hatchery stocked it with HBG several years ago. No mention of stocking with GSF. I agree that the fish pictured has a high % of GSF genes.

Next thing you know we will be doing gill raker exams by pic . Heck why not.

Does anyone know if the Universities have GSF and BG genomes ided so that DNA tests can be done. I would think that at least some of the sequences have been as studies address that.

I know I've mentioned this before, but of all the ponds I've ever managed or assisted in managing, there is only one fish that occurs without record of stocking--and it's Mr. Green Sunfish. I've got documentation of at least a dozen instances.

Jeff Blaser from Nebraska Game and Parks Commission has told me that streams that don't flow full time still can have a few remnant individuals when ponds fill that migrate down to the new body of water. He also said that after a rain event these fish will migrate upstream and find a way into a body of water. Regardless, I've seen this over and over and over and over............


My very favorite pond to fish was constructed by the NRCS about 16 years ago and was never stocked with anything. I was given the job of creating a new fishery. I went to check out the pond and thought I saw some fish activity. I threw out a jig, and boom, I caught a green sunfish. I proceeded to catch dozens more. Unbelievable really.

I went back a little further through the records of the pond stocking. As I reported earlier in 2002 the pond was stocked with 200 HBG. I went back further to discover back in 1998 the pond was stocked with 500 BG! So kind of ironic that we get the GSF. If I were able to get some size to them I would not care that they were in there since they are a food source for the LMB and CC. Hopefully by feeding them I will get some size to them! FYI other stockings in 1998 included 100 crappie. I have never caught a crappie from that pond...not even one!

Does this pond have a stream inlet or outlet ?
It is a dug pond with a watershed. Any permanent water up or down stream? What is the stocking history and when was last time it was emptied ?

I think IL just made my point. There have been both HBG and BG stocked into a pond that has LMB to at least 1.5lbs (several years of LMB) , crappie , CC and who knows what else. My guess is that there are all types of lepomis combos and probably some BG in there. BG (80 M) are more prolific than GSF( 2-10 M) and so are LMB (15-20 M) and Crappie (up to180 M) . BG have been documented to be 279 times more prolific than HBG in Mich. ponds which equates to HBG fecundity in the few hundred per year range.The pond was emptied and dug out at some point so I assume started over. The point is we don't have enough solid info to say what the population status is other than there are small lepomis , LMB and CC. What is done is done. I would suggest an assessment by someone who can do a through job of determining what is there before I stocked any more fish. Let the LMB do there job if they can. Depending on lepomis density it is possible that LMB will not reproduce offspring which reach spawning size when confronted with extreme crowding of small lepomis. It is fun to try via pics but not an easy job in this case from 1 pic. But lets have fun trying . Take pics of every sunfish that looks different form the others and post them . If we can get several different looking ones we will know more.

The pond back in the 1800's was a water basin for the steam engines on the railways. I have talked to many old timers who were told that it was more or less always a marsh land that was never over 4 feet deep. Approx. 20 years ago the pond was dug out, however not right since there was no silt pond. The pond is fed by a stream that often dries completly up (basically run-off from field tiles). Last fall an assessment was done by the DNR here is what the report said.

"Bluegill-31 fish ranging in size from 2.4 to 5.1 inches in length. It is obvious that a loss of blugill had occured sometime in the last 2 years.

Green Sunfish 78 fish, ranging in size from 1.9 to 5.5 inches. These fish are native stream species that are not usually stocked into lakes or ponds because of competition with more valuable game fish species. Nothing was collected that was of fishable size.

Hybrid green sunfish bluegill-10 fish ranging in size from 2.7 inches to 4.7 inches in length. These fish are created by green sunfish and bluegill spawning together under stressful situations. Once again no fish were collected that were of catchable size.

Blutnose minnow-16 fish 2-2.5 inches in length

Channel catfish 4 fish ranging from 20-24 inches length. These fish were somehow able to survive past stressful conditions in the pond.

After our sample, I was able to obtain 150-4" bass and stock in the pond as a stop-gap measure to get some predators back into your water."


While I appreciate the report, I see one big error in it. He shocked the pond to get these readings. This summer I caught over 30 cc in this pond that ranged from 19-26" in length. One more thing to keep in mind is that we had a major drought last summer and our pond level was down. Sorry I did not post this earlier I just became aware that this report was done.

What about the LMB history ? Do you think that one of the 4 in. LMB you put in one year ago grew to 1.5 lbs in a year. Any history of LMB prior to last year?

A shock survey only surveys about 10% of the fish often much less than that. There could easily be other sizes and types of fish not reflected on the survey. It is a good survey indicator but in no way tells the whole pond story. It is one good tool but just a tool not an answer.

That report helps a lot though for purposes of suggestions. Lets see what advice others have with that info. Do you think that the stream has water/pools year round or runs from or into other ponds/lakes where GSF could swim to your pond now if water was up or do you think they have been their for many years? It is important to know if they can be managed based on what's there or can more come from another location.

Thanks for your responses thus far. Bass have been stocked in the pond with both the 1998 stock and the 2002 stock. I believe the number was 100 in 1998 and 200 in 2002. Then with the recent stockings. Not sure what may be the issue here but I have not personally caught alot of LMB out of the pond. I must admit that most of my fishings in this pond were with my children though and I did not concentrate on them. The stream that flows into the pond does not touch another body of water prior to its entrance to the pond. It does quite often dry up and there is no standing water within it. I have been told that the GSF can be brought in by something as simple as eggs on a ducks foot when they fly from water to water. Either case, I know that it was either introduced by someone other than the village or brought in by wildlife. The latter being my best guess. Sometimes it seems nature finds a way to make things happen that we do not always understand. Just got the go ahead tonight at our board meeting to bring the rep in for the fountains and aerators. We will be going by his suggestions. Through talking with individuals in this forum and out I believe that the oxygen introduction could remove some of our fill in muck at the bottom of the pond.

Oh and I forgot to post that about a month ago I caught about a 2 lb LMB in the pond. The bass had a big full belly on it. I told the fish good boy and told him to go back to work as I returned him to the pond.

Got warm today so I took a vacation day and spent the day fishin the pond. I was very surprised to catch 6 14" LMB. Could these bass be the same that were added last fall at 4"? One thing is for sure they have enough small sunfish to keep them growing. It just seems like alot of growth in one year! Anyone else every see this?

Very likey those 14" LMB were two or three years post stocking. Since LMB can get conditoned to be hook smart it might be a good idea to regularly fish the pond and catch and release the LMB. This will make them harder for others as "fish hawks" to catch and remove your valuable and prized predators. If you want to read more about hook smart fish use the SEARCH feature to scan the old posts.

Thanks Bill, The most recent prior to last years stocking was in 2002. I do not believe the fish have been spawing in this pond due to lack of proper spawning bed areas. Perhaps someone added some of these LMB in the last two years. That seems to be the more likely. However when the DNR shocked the pond last fall he found NO LMB at all. So I am confused on this! I have fished that pond every year and have never caught a LMB prior to this year. Today I caught the bigger ones and a bunch of the recently stocked.

Went fishing last Thursday, it was a beautiful day. I caught 5 13-15" LMB. I was amazed to find this after the DNR study last fall. I did not catch any of the BG or SF since they would not bite. Perhaps they are all running for their lives with the recent LMB introductions.

We are adding a display aerator to the pond this fall. The guy who is selling it to us is a retired DNR employee. I asked him how they were getting in to the pond. He told me the myth of birds carrying them in is not possible. He told me that they are swimming upstream as someone said earlier. He told me that he has seen them do it. So it appears that I will never completly rid the pond of them, even after we dredge it. All I can do is get them under control then add the HBG in big numbers to get going in the right direction. Thanks for all of your help!

Okay folks with the now decent size of LMB stock...how long would one guess that I could cut down the GSF to a number that would allow me to introduce BG and HBG once again? Am I looking at a 4 or 5 year wait to get the numbers under control?

Illinois Longhorn, I would continue to stock adult size LMB. With lots of stunted GSF it's not very likely that the your LMB will have very good recruictment with the absence of a lot dense weeds or cover to hide in. Your LMB fry will simple not survive the GSF predation very well. This could be a good thing if your goal is to have a trophy bass fishery, with GSF limiting LMB numbers the remaining ones should grow fast and have excellent wr's. I have seen a similar situtation at private community lake here in Lincoln that has tons of GSF. One other thing you could do is to also stock adult BG too. I will defer to others on the actual stocking rates.

The LMB will control the numbers. BG (80M) are much more productive than GSF (2-10M) and will out produce them. The 2 species tend to segregate at spawning. Depending on your goal there may be no reason to wait.

If you are trying to keep clean genetics (pure fish) a very difficult job. However if what you want are a higher % of the fish that look and grow more like BG then stock adult BG ( pre- spawn male and female) at least 3 weeks before spawning time. No need to stock HBG (BG X GSF ) as you will get some anyway with as many GSF and BG as are there. The key will be the productivity of the pond and its ability to grow more lepomis ( BG and GSF are both lepomis) than are there now (a carrying capacity question). If you will be feeding them you should be ok subject to water quality.

Why not start trapping some of the GSF and removing them now. Can also seine and sort to reduce the GSF numbers.

I thought about trapping some....however I did not add any fatheads this fall. My fear is that if I trap too many I may be taking out too many thus starving my LMB! It is pretty cold here right now...we actually had some snow last night or I would try to find a bait shop to grab some fatheads for the pond. Man I wish it was spring! Perhaps we could just skip winter this year!

Is this another GSF? The larger mouth makes me think it is. I will keep trying to catch them to see if there are any BG left! Do the orange-yellow fins on fish tend to lean more towards BG than GSF? Just looking for some signs to look out for.

It looks more GSF than anything else although lower fins do not have well defined whitish or cream colored outer rims, nor does it have well defined dorsal and anal fin spots....so could be HBG. Also emerald mottlings on side of face are not well developed but the pic is a little rough.

other votes?

Definitely not a purebred bluegill IllLong. You won't find that big, yellow outer border on bluegill fins.