Pond Boss Forums MANAGING AN EXISTING POND Corrective stocking In need of more predation

As far as culling, I was thinking to remove only GSF because if I have large populations of YP and PKS I don't really need a third panfish. Is there any logic to removing all of the GSF caught in the second event? Should I stick to GSF that are smaller than the top end ie. sub 6.75 inch? My main focus is to improve the body condition and sizes of the other panfish and increase the amount of bass. Further question, if I am going to introduce more predators would more LMB be better than trying Saugeye? If so would that be a fall stocking or spring? For LMB growth rate context, in a previous "version" of this same pond, before a fish kill, my LMB would grow up to a max of 8 inch in their first summer so this slow growth is new and the main differences I see are less adult bass (0 vs seeing and catching) and much smaller sunfish (I had 9+inch HBG). So are we looking at stocking 10-15 ish 8-10 inch LMB? If so should I use the same hatchery or go with a different one in the name of "genetic diversity"? A few too many questions but any input is appreciated .

PondDragon,

One of the things I noticed was that your recaptures did not match precisely fish in the list. So IF the recaptures were fish caught twice on the same day, there may have been variation in measurement(error introduced by the one taking measurements or problems with the measurement equipment). I questioned whether to say anything but now that you voice concern ... I would just say ... continue to practice with your measurements and isolate the cause if there is noticed variation measuring the same thing multiple times. Also, they make weights of a specific mass that you can use to calibrate with. Use your best judgment and experiment until you are satisfied that your measurements are consistent.

Were it me, I would focus on the PKS and manage around them. I don't think you need the GSF at all (with the addition of the right number and size of LMB), but that said, they are playing a predator's role in helping to control some of the recruitment of your desired panfish. Be mindful of that, If you have 30 lbs of GSF in your pond, they are consuming a non-neglible weight of small panfish. Try to gain an understanding (using minnow traps) of how many YOY you have presently in the pond (and their distributions of lengths). Is there a need for GSF predation of YOY over winter? If not, then I would still track the weight and number of the GSF that you remove.

As to the question can you remove only GSF?

IMHO, no. First, I wouldn't add nutrients to your pond to push growth. You've had winterkill before and I would opt to stimulate growth by reducing populations. Removing GSF will free some pond foods for the desired species. It's not going to add the small fish that GSF were consuming (that were too big for PKS gapes). But everything else is, in theory, freed for consumption by your desired species. Based on your initial survey, GSF may comprise around 25% of your adult panfish biomass. This adjustment of increasing foods (per PKS and YP mouth) by less than 25% will be TOO SMALL to get really good growth (if you don't cull PKS and YP too). It will likely also be insuffient to stimulate enough production of YOY for your newly stocked LMB. You need between 35%-45% annual mortalitly of the adult biomass to support superior growth. So the PKS and the YP should undergo that kind of mortality. You want this mortality focused in near quality or quality sizes (5 to 8" for PKS). Fish that are big enough to harvest but that will thereafter grow slow if they are not thinned. Each year, you get a new crop of harvestable fish in those sizes. Reserve some of them for grow out to larger sizes. Invariably, they will recruit more than what would be ideal for growth ... If you don't harvest some.

IMHO, you need to remove 60% of your adult panfish biomass to initiate good growth and good YOY production. So up to 25% of that biomass could be GSF but you also need to take 35% of the existing biomass of PKS and YP. Additionally, You need to add around 10% of your existing adult panfish biomass with LMB that will be large enough by next season's end to consume YOY that have grown all season. Ideally, some of your earlier stocked LMB will have approached 12" in length by season's end. By season's end, perhaps as much as half or more of the adult panfish biomass will be recovered. The pond will still be below its maintenance carry and fish will be growing. You wan't to maintain it in this condition where they have not maxed the carry. This will be done by your predators and yourself through thinning (which might also involve trapping given your weeds). In this state, your pond is more like a new pond (remember when growth was good?) After more discovery, lets discuss how you can manage for the population structure you desire most.

With regard to the species of predator, IMHO it doesn't matter so long as they are stocked at sizes that get you the growth you need this first summer. It may be difficult to source other species in the sizes you need. But whatever size they are going in, if it is working, they should be large enough that 3" PKS are still occasionally on the menu at the end of the growing season. So what I am saying is that there is no magic bullet species that works miracles. Any large gape predator stocking could work and it could fail to produce optimum results if their number and their lengths are not right or if they are ill timed. If your YOY get ahead of your predators, then I would consider that a failure for YOUR goals. You want your predators to stay ahead of your YOY until the predators reach around 11-12" in length. Ideally, they are balanced about there. There should be enough of them so that YOY that ultimately grow to survive predators of this length are not so numerous as to be manageable by harvesting quality panfish. That is probably the definition of balance. Where predators only allow enough recruitment to support a harvestable weight of panfish while restricting the population such that the growth of survivors is sufficient to meet goals and balance with the mortality (both harvest and natural mortality). This may seem overwhelmingly difficult, but balance is painted with a pretty broad brush in terms of acceptable. Good fishing doesn't necessarily mean that growth rates are maximumized. Good fishing can fall within a broad range population structures and harvestable fish sizes.

Let's at least see your second survey before discussing potential stocking rates of LMB. From my perspective, in my own pond, I wouldn't worry about LMB genetics where I am focused on growing panfish. I would go the path of least resistance and do what is the right balance of convenience and cost.

Thanks for the input it is a lot of help. I have a very small seine net that has worked for catching YOY in the past, I will try that again and report back.

Also for the weights, the scale would read 0 to 5g heavy despite my best efforts to zero it so that is where the variation comes from. I will try a different method next time to reduce error but with small fish small errors look big.

In working with ideas of jpsdad, I would remove every 1"-3" panfish and all GSF over 3" that you can manage to catch. There will be despite your best efforts usually enough remaining small panfish to create a decent year class of 2025 panfish. I would stock some 7"-9" LMB regardless of the source since your goal is mostly nice panfish. IMO all LMB from a reputable fish farm will grow to very respectible sizes if they are not over crowded and are able to get plenty of appropriate sizes of forage.

Alright we got more data. Not as much as I would like because I threw my back out yesterday but still got 61 fish (and a painted turtle). Unfortunately (or fortunately) there were only 7 recaps. Here's a snapshot
6 recap GSF (6-7in)
1 recap PKS (6.25in)
8 new GSF avg 6.4 in 84.5g max 7.25 in 113g min 5.5 in 61g
6 new PKS avg 5.9 in 73.3g max 7.25 in 137g min 4.75 in 31g
39 new YP avg 7.6 in 80.3g max 9.5 in 156g min 6.25 in 48g
1 new LMB 7 in 64g

All fish were held back in a tub while fishing to avoid recaps. I did not end up harvesting any fish as it was rather late but I might try again tomorrow. Side note, during the day I was able to see a couple bass in the pond; a few sub 2in YOY, a few 6-8in and I fed one bigger bass a big frog, I would guess 14-16in.

Here is the full data set. I will point out that the data is definitely biased as we only fish from the dock, I will try to take the canoe out next time.

Ponddragon,

I'll reply tomorrow. Wanted to ask if the new fish today were marked prior to release. Also, hope your back gets to feeling better soon.

Yeah I marked them with a fin clip on the lower caudal so we can tell them apart from the last fish

Sorry to hear about the back. Hope it gets better soon!

Great work performing your survey and recording/sharing your data. To begin, lets discuss the population the surveys suggest and some other considerations regarding potential biases that can increase the uncertainty of the population estimate. In your first survey you marked 69 unique fish. In the second survey, you caught 61 fish of which 7 fish were recaptures. These values suggest that your total population of fish is 601. In a .73 acre pond, that is 823 total fish per acre. Of the 601 estimated, you identified 124 unique fish (roughly 20.6% of your estimated population).

With mark and recapture, the larger the number of your samples (especially the second survey), the more reliable and less uncertain the estimate. I do consider this to be a good sampling but given the second survey comprises less than 11% of the population, it has a higher uncertainty than if the second sampling had been 22% of the population. In fact, the uncertainty would be halved by doubling the number of second survey samples. There will always be some level of uncertainty when the sample number of the second survey is less than the total population but the purpose of this statistical method is to make a good estimate of the population with acceptable levels of uncertainty WITHOUT having to count each one. By and large, mark and recapture does this so long as biases are not extreme in the sampling method(s).

It is especially important that the second survey be unbiased. Especially with respect to the first survey. Both of your surveys are by fishing with the same method (earthworms on a small hook). So there is little bias introduced by the method but it isn't bias free. Generally we agree that some fish after being caught are more difficult to catch again. This effect, would introduce a bias to overestimate a population. An electrosurvey eliminates this uncertainty because it ability to produce samples doesn't depend on vulnerability to angling. Even so, to be a good survey for mark and recapture, it must not introduce bias that affects the sampling of marked fish. Let's say the marked fish were caught at 25 ft depths but the electrosurvey only worked in water of 12 ft depths, then the electrosurvey would introduce a negative bias on recaptures (thus increasing population estimates).

Another important bias is geospatial bias. This would be especially important for fish that are not ranging considerably. If there is a equal chance that any fish in the population could be sampled in the sample areas then this would minimize bias. Also, if the second survey gives no preference to geospatial areas (being no more biased toward other areas than where the marked fish were captured) then this would minimize bias. If fish are territorial and not likely be impartial to location, then there is possible geospatial bias where the geospace of the samplings have been limited. For example, if your surveys occured in 1/3 of the geospatial extents of the BOW AND the fish are territorial, then you may have a great population survey that are limited to the extents of sampling area. In doing your sampling, these considerations should be given thought and decisions made regarding trust of the findings and adjustments if deemed prudent.

For now, I think we can move forward with estimate of the population that your surveys imply. While I do think they could underestimate your populations, I also know that careful future sampling will prove to make that evident. For example, if the proportion of unmarked fish is higher than anticipated, that would suggest the surveys underestimated the population. You describe the BOW as being fertile with much chara and (some duckweed). Chara favors water of good alkalinity. Duckweed favors high fertility. So I think there is a really good chance that your pond carries more than mark and recapture presently suggests. Also, you mentioned not having good access to all of the pond. Geospatial bias may have affected the population estimate. Presently, your survey suggests a standing weight of adult panfish of around 150 lbs per acre. Give some thought to geospatial bias and let me know if you are satisfied that all or most of the pond was sampled without geospatial bias.

I think there was a heavy bias so I will be resampling today while fishing the entire pond.

Second sample completed, 39 new fish and 13 recaps. this was done with the canoe so a lot less location bias. The only difference noted in catches related to location was when a little into the swamp the only fish caught were small PKS, everywhere else the fish were homogenous with species and recaps.

Recaps:
GSF 8 - 3 from yesterday and 5 from last week
PKS 3 - All from last week
YP 2 - All from yesterday

New:
GSF 8 - avg length 6 in, 64 g - max 6.5in 79g, min 5.5in 50g
PKS 19 - avg length 5.5 in, 54g - max 6.5in 100g, min 4in 31g
YP 12 - avg length 7.4 in, 75.3g - max 8.25in 113g, min 6.5in 46g

Here's some raw data, LMK if I need to make it easier to understand in some way

OK, Great. So the first thing is that it seems the fish have been moving around a lot and fishing other parts of your BOW resulted in no reduction of recapture per sample size compared to yesterdays survey. This seems to suggest that your 2nd survey was not geospatially biased. So yesterday, you had 7 recaptures from survey 1 out of 61 fish caught. Today you had 8 recaptures from survey 1 out 47 fish. I did not count recaps from yesterdays marking because I am going to treat todays survey as an extension of yesterdays 2nd survey (and we don't want to count the fish of the 2nd survey twice). So between today and yesterday, you caught a total of 108 fish with 15 recaptures from the first survey. It may be possible, that 1 or more of the recaps that we are counting today were also caught yesterday. If this be the case, then we are counting 1 or more recaptures twice. If this happened, this would scew the population estimate down. Since the fish are not uniquely identified (where we could be certain), we can't know for certain whether any recaps today were also counted yesterday. In any event, combining the two days as the second survey, we get an estimate 497 adult panfish (680/acre) compared to 601 adult panfish (823/acre) from yesterday's survey data. To be safe, (considering we don't know if any of todays recaps were caught today), we could take an average of the two and go with 549 adult panfish (752 /acre). That equates to around 137 lbs of adult panfish/acre (tentatively based on the average weights of survey 1). To be sure, I "feel" like you should have more standing than that but lets not argue with the data. Let's work with the average number.

Presently, if you marked the 39 new fish today, you have (69+55+39) 163 unique fish marked. That would be 223 adult panfish per acre that are marked. Of those 163 marked fish, 35 of them are GSF and so you have 128 marked fish that are either YP or PKS (your preferred species). The marked preferred species per acre is 175 per acre. If you removed all GSF AND unmarked preferred panfish until the look back of 100 catches were only 50% unmarked fish, then you would have in the neighborhood of 350 adult preferred panfish per acre. This is plenty, especially if your standing weight is presently only around 137 lbs/acre (though I may adjust this number after thorough review of the totality of the data you've collected). So let's stop marking fish and start removing any and all GSF plus lets also remove unmarked PKS and YP until the look back of 50 catches for each species is only 50% unmarked fish. If this happens with YP first, stop removing YP and continue removing unmarked PKS until the 50 catch look back is 50% unmarked PKS. This action has the potential of adding and average .15 lbs per adult fish on average which is close to a doubling of weight. This assumes the population numbers have low uncertainty and that fish less than adult sizes are not very numerous (which have up now been not numerous in your surveys). Start culling now and try to reach the look back before ice up. Continue after ice out if you didn't reach the look back. You will be keeping a record of all fish caught, marked fish which are returned as well as the culled unmarked fish. If the population estimate from your surveys are close to the actual values, then you should expect to reach the look back goals after removing ~ 400 fish. If it takes substantially more fish removal than this, then we underestimated your population and standing weight. I don't think it will take much less, but if it does, then we may have overestimated your population. However, it works out, we are going to use the feedback of your ongoing culling efforts to improve our understanding of your BOW's carry. Improving our understanding of your carry, is I think, necessary to making a better supplemental stocking of predators. Let's get more data before making a recommendation for the LMB. There is enough time between now and when you need to stock them next spring to make a lot of progress on your panfish look back goals.

I will analyze all your data collected thus far in greater detail and share any additional inferences or adjustments as required after I have concluded that analysis.

Thanks for the help, I will plan on culling next weekend. I might also try to get a fyke net ordered to help catch fish faster. The only thing I will add is that because the vast majority of recaps was GSF it's starting to look like I have far less than 100 GSF. My bad math puts the estimate for GSF somewhere between 60 and 70 fish in the pond, but we'll find out once we start removing them. Anyone have any input on size of fyke net to get?

That's the reason why electroshocking surveys are done. Fish that don't bite the lure/bait are also sampled........

For 3/4 acre pond and wanting a fyke net I would buy as small of one that is made. Fyke nets are usually fairly large compared to small fish and minnow traps. I built a small fyke net for a fish sampling study that I did for a pond boss conference. Basic box was around 2.5 ft on each side. Leads or wings can be as long as you want them. Instead of buying a fyke net consider buying or building a couple larger fish traps such as a Z Trap or from this company. Larger traps are easier to handle and use compared to a fyke net that is designed for use in larger bodies of water.
https://ktraps.com/

One can put leads or a wing or wings on a larger fish trap to have it catch more fish. A fyke net is just mainly a box type trap with wings.

Would something like the K traps chub trap do well at catching adult panfish? I also worry that an all metal trap would beat up the fish, is that a problem or not?

I catch panfish in my minnow traps. Sometimes there are GSF in there that do not look like they would actually fit through the two small entrance holes ... yet there they are! I don't know the set up of your chub traps, but that general style of trap is usually effective for panfish.

As regarding your desirable fish getting beat up: How often can you run your traps? I have not personally used z-traps or k-traps in my ponds, yet lots of people of the forum use them in their ponds that include many valuable fish. I think if you are able to run the traps often, your fish damage will be minimal.

I'll be able to run them as often as needed, I think I will order a z trap today as see if I can get it soon. Is there any brand or company that anyone has used before/trust?

I bought my ZTrap several years ago from Reel Texas Outdoors. The problem I had with it is the seams were just wired together and I considered the trap way too "wiggly". I took good quality construction adhesive and coated all the joints with a bead of adhesive. Trap is now very ridgid. I also spray painted the whole trap dark green / brownish to imitate pond bottom colors. Trap works very good when it sits relatively level. When the trap sits on a steep slope the catch rate decreases.

For on fairly steep sloping pond banks my best traping success is with using cylinder traps or oval opening homemade traps. I have many types and sizes of fish traps; many of them homemade. For sloping or steep pond banks,, I like the cylinder KTrap styles. I make many of mine with different mesh sizes 1/8" up to 1". KTraps - River Trap would work good for using wings attached to or close to the trap. The trap would then effectively be a Fyke Net.

NOTE Reel Texas Outdoors has a new ridgid version of the ZTrap. Shipping for me cost almost as much as the trap!

I've seen two versions of these traps (many different designs). Is there any preference between coated and bare metal versions?

My preference between coated and bare metal versions is for the bare metal because YouTube testing and my experience is the bare metal catches more fish per trap set compared to the coated version. IMO the coated version allows the more cautious fish to avoid the trap. I find that LMB will not enter either type of trap. LMB must be inherently trap smart?

When I get a bare metal trap, I spray paint it to colors that blend in with pond & stream bottoms.

I think I'll try the bare metal K-traps river trap and then a lead line that will work as a seine as well so I got some options for sampling