Pond Boss Forums STOCKING A NEW POND Types of fish to choose Tilapia with Winterkill

I was watching the Pond Boss live on FB yesterday and there was some discussion on Tilapia that got me thinking. Had a couple of questions but the feed got cut off before I could ask. Both side of the equation were discussed on Tilapia as supplemental forage and grazing of plants and each had varying stocking amount(s) recommended.

For FA control it sounds like smaller sized Tilapia are better at eating FA and stocking rates were a little higher.

For forage I suspect this somehow links to "preferred" food size compared to size of the predator fish, in my case LMB.

Not pulling a trigger on this in 2024 for sure. 2025 would be the soonest this could come into play. With the winterkill a virtual certainty on water temps for my area. What I'm curious about is what would be the stocking size on a FA vs Forage basis be?

Is the goal to stock fish that are large enough to spawn / not be eaten or stock a higher number of smaller fish that some may be eaten and some will grow eating FA until winter/predation takes them out?

Just me trying to learn. As I said....no intention of adding them to the pond this year for sure.

You WANT them to die during the Fall. That allows the bass to gorge themselves on the slow swimming fish and the scavengers take out the bigger dead fish from the pond, removing nutrients.

Here in Indiana for FA control we stock at the rate of 40#/surface acre and use fish that are 6"-9" in length at stocking.

I think I have seen this same confusion in other threads about using Tilapia for the control of FA.

Question for the tilapia experts:

When you stock tilapia that are 6-9" in length in the spring, is all of the FA control prior to the winter kill due to consumption by the broodstock, or do the tens of thousands of spawned Tilapia also eat a significant percentage of the FA?

I believe all sizes eat FA. The little ones get big, and the big ones get bigger, on algae (and what fish food they can swipe from the fringes of the feeding area).

Every big Tilapia I have ever cleaned (I remove in mid-September onward) has had intestines full of FA. I have only cleaned a couple YOY; they were full of FA too.

All of them eat FA and other stuff.

All sizes eat the FA, BUT we've stocked tilapia that have been grown for food fish and are mostly male, then stocked tilapia that are 50/50 male/female. At the same stocking rate, the 50/50 mix will control a LOT more FA because of all the young ones that are produced. (last part is my thought).

Thanks esshup, that is the closest answer to the question I was attempting to ask.

However, I still didn't ask my question clearly enough.

I have read several times on the forum where people have complained that they stocked tilapia, but they didn't even make a noticeable difference in their FA. However, they may have stocked too late for the next generation(s) to make any significant dent in the FA?

If the stockers eat 20% of the FA consumed in a given year, and the subsequent generations eat the other 80% consumed, then it is very important to facilitate the spawning of the stocked tilapia!

I would therefore conclude that it would be a management goal to stock the tilapia at the earliest "safe" date so they can more quickly initiate their subsequent breeding cycles.

I guess that leads me to three new questions:

1.) Any estimate of the % of FA consumed by the initial stockers versus the % consumed by the subsequent generations for "single-year" tilapia? (I know that is a nearly impossible question to answer. Did Rainman ever discuss that since I believe he delivered tilapia year after year to some more northerly ponds?)

2.) If the subsequent generations matter a lot, then is there anything a pond manager can do to aid spawning success of the tilapia?

3.) Has anyone observed a tilapia kill because they introduced them too early in the year and a cold front or cold rain wiped out their stockers?

(Even if the original stockers are responsible for eating 95% of the FA, then determining the earliest day to put them in would still be very important. Stockers getting more "eating days" and being much larger at the time of the winterkill would definitely provide much better FA control.)

P.S. I have read that tilapia can spawn year round, and that female tilapia can spawn every 17 days under ideal conditions! I assume that means a fish farm in equatorial Africa. Any ideas on observing tilapia spawning in the temperate zones of the U.S.?

P.P.S. Would it work to have a very shallow grow out pond to jump start your tilapia production? I am imagining a shallow pond that reaches a "safe" water temperature much earlier than the main pond. Create some good spawning beds and add some tilapia brood stock. Add a bunch of loose hay(?) to get a bunch of zooplankton going for the fry. After the fry hatch, move the parents to the main pond if the water is warm enough to avoid cannibalism. Move the 10,000 tilapia to the main pond as soon as they are beyond the mouth gape of the BG, or any other small, numerous fish in the main pond.


Just throwing out ideas for discussion since controlling FA and tilapia seem to draw a lot of questions from newbies and experienced pond managers on the forum.

I'm glad you asked this question boondoggle as I'm almost 3hrs south of you and have interest in tilapia. Looking forward to where this discussion leads.

From my reading they are sexually mature at about 4" and grow very quickly. Stocking 6-9" would likely put them out of range of all but the larger LMB.

It doesn't sound like there is a difference on stocking size for FA control or Forage.
.....I have however seen stocking ranges from 20-100lbs per acre depending on the severity of the FA.
.....I have seen/read stocking ranges from 5-20lbs per acre on the Forage side.

So far, I'm not having an issue with the FA and don't have LMB in the pond (yet) to worry about the forage. My goal was to do a little research early so that when I did need to find some I wasn't just buying the wrong sized fish.


Glad I could help Catscratch....I'm looking forward to giving these guys a try at some point. I suspect that as my water matures a little and the LMB get stocked....I'll have a use for these little fellas. Maybe in 2025 or 2026 when the LMB are able to eat them.

Rod I am short of time to answer the rest now but will try to get to them this evening. BUT to answer the above question, I have found out that you HAVE TO kill the FA 4-5 days prior to a week post stocking the tilapia or they CANNOT eat all the old algae AND the new growing crop. Even at 100#/acre they cannot eat both old and new. Been there, done that in my pond. I use my personal pond as a test pond that way the owner can't get that upset with me.

At 40# per acre 50/50 M/F if you kill the FA, they can keep up with eating the new stuff. If it's really, really bad you might have to treat it once or twice more that year, but that also depends on the water clarity and pond depth. If it's a 1 ac pond with <36" visibility (secchi disk) then they should be able to keep up with the new growth IF the tilapia stocked are 50/50 M/F.

Thanks for the additional input, esshup.

I have noted your previous advice in my pond notes of: algaecide first then tilapia - if you are really fighting FA.

Second guessing my plan a little after watching the pond develop a little over the past week or so.

We currently have YP, Northern BG, RES, GSH, FHM stocked in the pond. There was 1 5" SMB and 1 5-6" SAE stocked at the same time the YP came in early this spring. Have seen a few small frogs (no tadpoles) and one small turtle. LMB should be started this year.

Water clarity varies a little but generally not greater than 8" on the Secchi Disk. I have sent off samples for testing with Texas A&M on baseline and water clearing which will likely be back next week.

We are working to get some pond plants established - Iris, Pickerel Weed, Duck Potato, and adding some Detective Erika hopefully later this week.

A few pics attached. I think this is primarily planktonic in the pics. Not an expert here but there are no mats floating in the water to say it's FA.

This evening the wifey and I ventured out to the pond to watch the fish feed and relax a little after work walking around the property and the pond. Starting to see the riprap in a few of the areas being engulfed in FA. Which leads me to my second guessing of the plan of holding off on Tilapia until 2025.

We will likely be treating the water with something to help clear up the turbidity in the coming weeks. My guess is with the additional water clarity the FA will have additional room to grow as the sunlight is penetrating deeper in the pond.

Thoughts on a small stocking 3-5lbs (1.5 acre BoW) of Blue Tilapia now to manage the small foothold of FA and add a little forage on to the pond even if they outgrow the edible size of predators? We should get cold enough here for full mortality of the Tilapia this year.

In my experience over the past 10+ years stocking Tilapia, its an all or nothing thing. Stock enough per surface acre to eat it all or save your $$ on Tilapia and spend it on Cutrine Plus. You don't want the stocker Tilapia to be eaten, you want them to spawn and the little ones can work on the FA and become food sources themselves.

People that don't listen invariably the next year say "I'm not going to stock them this year, I put some in last year and they didn't do what they were supposed to do." I've already told people this year that we wouldn't sell them Tilapia if they didn't want to listen to our recommendations, because we don't want people to give us a bad reputation. "We bought tilapia from them but they didn't work." They tend to forget that they didn't listen to our recommendations and didn't stock enough, so we are taking a different approach this year to limit any "bad reviews" that would be associated with us.

Thanks esshup. I'm not thinking the FA is "all bad" due to our shortage of plants. Was hoping that the GSH may use a bit of it for spawning while we are working on the plants we really want to be there. Understood on the don't want bad reviews part. I don't think I would get stuck in that trap. Anything "you" do after seeking advice and then doing "your own thing" puts the responsibility back on the guy that made his own plan.

If we get the pond plants going however......would likely be much more aggressive on FA control methods.

My guess on the algae in the pics above look right (planktonic or phyto vs FA)? We aren't seeing mats floating "yet" but from 04.07.24 to 05.12.24 there seems to be more and more each time I'm out there. Not a bad thing either way....water is still new. Just want to make sure I'm on the right path with my observations.

Boondoggle,

Can you just take a long stick with a little fork or small branches on the end and sample for FA below your secchi disk depth?

I would sweep it around down to about 3' deep where you have some firmer substrate on the bottom and maybe also sweep through the edges of your brushpile. If you get FA on those sampling efforts, then you know it is coming.

OTOH, even though everyone hates it in their fishing pond, you might just observe your FA cycle for a full year since you aren't fishing yet. Save your budget and time, and then go full bore next year if that is needed?

Sounds like a good good reason to get the boat out! Good suggestion Rod. Might try to grab a pic of what I'm seeing on the rocks as well.

I agree on the cycle part....I think my efforts will be kind of a graze FA and bonus forage should the LMB get to where they can take out some of the Talapia spawn. We stocked 3-5" on the BG so hopefully get a spawn or two off this season and try to preserve the BG until later in the fall / winter with the early die off on the Talpia.

3 years of experience with Tilapia . 1st 2 years couldn't find nearly enough, 3rd year at 15 lbs per acre , what an improvement. Either stock them, or don't , don't mess with less than 12 lbs per acre , I wish I could find at least 15 lbs per Acre, would prefer 20 -25 lbs . They have been wonderful, both forage and FA control

Looks like these guys prefer some gravel, rock or sand to spawn in and they spawn at the same time the BG are on the beds. Does a separate spawning area need to be created for them or co-mingling with the BG is acceptable?

Most of the searches I've come up with on the internet are more aquarium based with pots and pvc tubes. This doesn't seem to be really needed for outdoor pond applications.

We do have a couple of areas in the pond in the 1-3' water ranges I could adapt if needed....figured I would check to see if they were more independent like LMB or more communal like BG on their spawning needs.

Boondoggle, did you perform an exhaustive search of the forum?

In my (fuzzy) memory, there have been lots of threads on adding tilapia. There have been lots of threads on spawning habitat for BG, LMB, SMB, YP, CC, etc. However, I don't recall any threads on spawning habitat for tilapia!

It is kind of related to my question upthread about how much FA is consumed by the tilapia SPAWNED in the pond when the total population of tilapia are killed every winter. If you don't find any good info in the archives, perhaps you need to start a new thread specifically asking about creating good spawning conditions/outcomes for tilapia. I bet you would eventually get some good responses from the people that have introduced tilapia into their ponds over several years.

I did try to check the archives on Tilapia and checked the university of google as well. My results on habitat for them on spawning in the forum were not very fruitful (might have missed it). Google returned some results mostly for aquarium type breeding where the fish were isolated one or two males with multiple females.

From Google: Reproduction - Just like many other African cichlids, the Blue tilapia is a maternal mouthbrooder. The male will build a nest and defend the territory. If his displays are not enough to fend of intruders, he can engage in mouth fighting.


I have the following so far:

Spawning Habitat: Rock, Sand or Gravel based and they are nest building
Spawning Temp: 68+ degrees

Looking like they need a separate area to me. Likely same or similar type application on spawning habitat as LMB.

Tilapia have been spawning just fine on mud and silt in my ponds for 12+years.

They are not colony nesters like BG. Once eggs are laid and fertilized, they are carried around in the mouth by the female.

So what would a pond manager do to help the tilapia the most for that type of reproduction?

Water quality/chemistry? Pamper the broodstock tilapia so they can best make it through the stressful period of spawning and raising the young? Something (cover or food sources) that would increase the survival rate of the fry?

Good question, I just toss them into ponds.

Very best way to help tilapia for the best reproduction is to have no bass or other aggressive larval / small fish eating predators in the pond. The fry once forming all their finage begin eating the smallest "sprout's of algae and forms of filamentous periphyton growth. Loss of high numbers of fry / larvae is a loss of one's algae eating army. Keep the foxes to a minimum or out of the tilapia chicken coop if your main interest is tilapia for algae consumption.

I have read a thousand long-winded replies on Pond Boss that basically boiled down to, "It depends."

I chuckled out loud to read a reply that was just the opposite!

Bill (and all others),

Except for "swimming" ponds, I think most people have reducing the FA with tilapia as a secondary objective after their primary fish management objective.

So, for example, if a person has a LMB/BG pond, and small BG eat lots of tilapia fry, then there really isn't anything the pond manager could do to help the tilapia fry survive to adulthood.

However, can you list some "supplemental fish" that you think should be excluded from a pond if you suspect the pond will have significant FA problems?

I am thinking about things like Golden Shiners, or Crappie that might really hoover up the tilapia fry, and therefore you should NOT include those species in your pond stocking plan if you think tilapia are going to be an important part of the pond's management tools.

Definitely not a pro here but I'll chime in with my thoughts on why we moved forward with Tilapia at our place. Right, wrong or indifferent they are in the pond now and we'll see how it plays out for the year. The good news is that there's nearly a 100% chance that the Tilapia will die this fall as our temps for this area will likely have some amount of ice on the pond taking the water temps below critical for the Tilapia we stocked. I was hoping for Blues but settled for a Nile/Moz cross (availability).

Pros

1. The Tilapia will graze the FA we started to see on the riprap around the pond and provide an unplanned additional forage base for YP and LMB as I wasn't planning to have Tilapia until 2025.
2. My understanding is that the Tilapia in many cases take some of the pressure off of the BG/RES populations due to their prolific breeding which, in a bass overcrowded scenario, allows the BG/RES to repopulate balancing the pond population.
3. I have read that Tilapia become sluggish at lower water temps and in one article the swim in circles like a fish in distress. Predators gorge themselves on these fish which can only lead to potential weight gains.

Larry Harley - Texas Tilapia

Cons

1. The Tilapia may eat some of the pond plants we are trying to get established thus slowing down some of our work. Hopeful that our 1/4" wire mesh will help to prevent this.
2. Some of the Tilapia will likely outgrow the gape of our predators (LMB, and YP).

For my personal situation I looked at the pond as Quazi bass overcrowded as the forage base is new. We are seeing small fry in the 1,000's between 1/4 -1/2" in multiple areas of the pond. Assuming the BG will spawn this year as we stocked 3-5" - Hopeful we see 2-3 spawns but that's in Mother Nature's hands. Stocking the Tilapia was hedging our bets to hopefully allow full establishment of the BG/RES/YP/Shiner population with some or more limited predation on them over the winter by the LMB.

Would be a complete bonus if the LMB were able to gorge on some of the Tilapia going into the winter.

To your question on forage fish (BG and Golden Shiners) eating some of the Tilapia. My guess is that they won't have an impact overall. Both of them have mouth gapes that are small enough that the Tilapia will outgrow it. YP may be able to put a dent in them but that would likely help the BG/RES populations to get established. LMB will likely be the biggest player here as they can take the biggest bite but if the stocking quantities are right.....there's a buffet for them at the end of the year as water temps drop.

Looking forward to some other comments. Hopefully I didn't shoot myself in the foot.

Thanks Boondoggle.

I think watching the development of your pond will be a good test case. Your are roughly in the middle of the "use tilapia for a single year" zone.

I hope you and your family get great enjoyment from your pond this year!

Our typical Tilapia stocking is for FA control, not forage.

SRAC 0283: Tilapia: Life History and Biology
https://srac.tamu.edu/fact-sheets/serve/53

Reproduction In all Oreochromis species the male excavates a nest in the pond bottom (generally in water shallower than 3 feet) and mates with several females. After a short mating ritual the female spawns in the nest (about two to four eggs per gram of brood female), the male fertilizes the eggs, and she then holds and incubates the eggs in her mouth (buccal cavity) until they hatch. Fry remain in the females mouth through yolk sac absorption and often seek refuge in her mouth for several days after they begin to feed.
--------------------------------------------------------------------------------------

Tilapia have a higher early survival rate than LMB, BG etc. because of above parental reproductive method.

Tilapia post from 2013

Rod,

I stand corrected and there was some really good info in this post from some of the more experienced guys here on the forum not to mention Mr Lusk chiming in too.

Wasn't trying to lead anybody off the right track and wanted to make sure I provided the right info...some of this has been talked through before...

Enjoy the read, hope it helps with your questions.

Boondoggle,

Thanks for posting that link into this thread! That is a good one.

I read that one a long time ago. I am pretty sure it was in the back of my brain somewhere when I was asking questions about helping the tilapia fry reach maturity.

I think that is an important step for increasing the forage value of tilapia to the other fish in the pond AND for increasing the ability of the tilapia to combat FA.

I know that process is very difficult to study and quantify. Just wanted to see how much our knowledge base has advanced in the last few years.

I've been watching the fish a little, reading the threads and searching the internet for a little info on Tilapia. Curious if the fans of these little fish have any opinions they can share. My question is on evasion from predation from LMB. I've seen posts about LMB teaming up on these guys only to fail on attempts to capture and TP sidestepping the attack from LMB. Other posts indicate that some of the benefits include additional forage to the pond/lake that helps to save the BG for later in the year after the TP have cycled out due to low water temps.

Are BG easier for the LMB to capture in warm water and then the tables turn as the water cools off in the fall? Any experience or opinions here?

I would be hesitant to say BG are easier than TP in warm water. Could be, however. Perhaps a good test of that would be where TP and BG prey of nearly identical weights are available for consumption to an appropriate sized LMB. If we can agree that the LMB will target the prey that requires the least investment of energy ... AND ... if one of the two species is much less resistant to predation then the weaker prey species will be eliminated whilst many of the other prey species still remain.

Another take on this would be to do each species separately and determine the time it takes to consume them all. The easier prey species should be eliminated in a shorter period of time.

Good question. I will check. A WAG in same sized BG and Tilapia the tilapia would be easier to eat. BG have less of a fusion form and have erect spines requiring a larger gap on the predator.

We often talk about the preferred SIZE of forage and SHAPE of forage for the predators to consume.

Does anybody know if fish "escape speed" or "pond habits" make a significant difference?

FHM are typically referred to as slow-swimming minnows, and we know that they are typically eliminated from a pond once the predator density is high enough.

I have seen many videos of BG slowly cruising around brush piles. If a bass was able to hide in the cover, it appears the BG would be an easy ambush meal.

Shad like to hang out in the open water in the middle of a pond. No cover for them to hide, but if they are fast swimmers, there is also no way for predators to approach unseen.

I assume the "escape speed" of tilapia goes down significantly when they start to get lethargic due to cold water.

Do "sleep" modes vary among or common pond forage species. Even I can catch a greyhound when it is snoozing in its dog bed!

Just throwing out more questions for discussion. I have no idea if it matters in the real world, or it is already basically accounted for in our "rules of thumb" for stocking forage.

P.S. I was just thinking about fish vision in the discussion above.

While predators certainly have a preferred size of forage, how good are they at measuring?

If I see four BG on video swimming in the same direction, I can easily pick out the largest BG and the smallest BG. (If there is much size differentiation.)

However, how does a bass measure the size of a solitary BG? A 2" BG that is two feet away would look awfully similar to me compared to a 4" BG that is four feet away. Especially in lower light conditions when bass like to hunt.

I would guess bass were pretty opportunistic and would take a BG over a large size variance if that BG wandered into the parameters of a "highly successful hunt" for the bass.

Further, it is difficult to gauge the RW of a BG when viewed only in the profile aspect. Likewise, if you only view a BG from straight in front, it is difficult to accurately assess its length.

Good thing bass are MUCH smarter than I am at catching BG!

Seems to be a bit of different behavior between the fish if I am observing them corrently.

BG at my place seem to relate more to habitat we have placed.

TP at my place seem to continuously move in a pack of 50-100 like sized buddies. Have multiple packs of the TP that range in size from 1-4" Pretty evident that there are larger packs out there too in the 4-6" range. Our largest sized TP seem to be in a pod of 2-6 (guessing these are mating males/females).

Not uncommon to see the LMB to crash the shoreline in attempts to capture the roaving horde of TP..

The thing I think I am seeing is that the BG numbers are down (easier to catch?) and the TP numbers are the same (harder to catch?) and then the tables start to turn when the water cools off as the TP get slower or struggle?

I like your report that the BG and TP have two different modes of living in your pond.

Bass in a good hiding place oriented near cover have BG to eat.

Bass that like to bull rush a school of fish have TP to eat.

All of the bass go home happy at the end of the day!

I like all the thoughts presented but I keep returning to Eric's wise words, "same sized BG and Tilapia". This qualifier is essential to the comparison because size is the most important variable for either species with respect to their own resistance to predation. Size, by and large, is more important than species. Larger prey are more resistant to predation than smaller ones. It would be acceptable to ignore species and consider only size when projecting susceptibility to predation. Size has a lot to do with concepts like relative speed for example. There is a lot out there on the subject of the size of prey.

Yep, grocery size matters. A large bass or cat would lose weight trying to catch and eat minnows. They need prey that is 1/4 to 1/3 their size. That’s why we concentrate on feeding bluegills. And those prey fish need to be fed enough of the right groceries to meet the needs of the predators.

Well, I'm at a loss. Fish are in the 9"+ to 10"+ range. That would put the forage need between 2.25 - 3".

The water inlet and outlet are nearly the same on numbers of fish present and the section that is between them is the West bank where we feed from.

Water Inlet

I see packs of these guys in the inlet, along the west bank, and in the emergency overflow area(s). Looks like the right size to me.



I'll keep working on it. Thanks for the replies and thoughts.

The answer may be in what you are not seeing. For example, if the LMB are currently lower RW than 30 days ago, what was present then that isn't now? What were they eating, proportionate size wise, that helped them be RW 150s, that isn't available now because they were eaten. One possibility on your BG question may lie in which forage grows faster. For example, if BG grow slower (not saying they do), wouldn't they be more vulnerable to predation? Predation may be the culprit for seeing fewer of them as you suspected above. There are lots of ways to look at things like this but it is always good to flip the coin and examine the other side. In the end, LMB eat what they can and all they can. Its probably a matter of can at the moment. When the TP begin declining due to colder water. This will redefine what can be eaten on the TP side of things. Should be a buffet going on if they stay pretty much the length they are now.

I have ask this before, How much confidence can you put in RW anyway ? It's just a suggestion, Is any RW chart for a LMB under 10" really skewed in the lower weight direction ?
Are there other outlying factors in fish growth in this particular pond ? Newish pond, lower nutrient load ?
Is a 10" - .61# LMB really is a great size with great growth (YES)
What is better for a 12 month old LMB ? 12" - 1.30# ( 144%) or 13.5" - 1.53# ( 117%) , You have all shapes and sizes
Is the forage really there, you just can't see it ? When i eradicated my pond we thought there were very few fish in it, There happened to be over 4000# of fish
I totally disagree with "a LMB will eat what they can and all they can" Every day I observe my LMB and my BG swimming together. The LMB sit there and look at the forage and don't mess with it.
Is there some sort of transition that goes on at 6 months (10") where the fish gains length more than weight ?
I'm only typing this because I am seeing the same REAL WORLD results that Boon is. LMB and SMB had stupid big RW numbers up to a certain size then that number went way down when they hit a certain age and length. Maybe the sample size isn't large enough. Boon is doing a great job and I have learned a lot from his venture

I agree 100% with this.

Just a thought. Lots of good questions. May be able to answer some questions - in a vacuum. Problem is we don't live in a vacuum. Often, we just have to say we really don't know the answers in a particular situation due to the many factors at work. Some of lake management is science, some is experience with a particular water and some is art.

I just spoke to our regional Biologist for the Oklahoma Department of Wildlife Conservation and they just completed a study on using Tilapia for forage fish. They conducted the study on 4 different ponds. They electro fished, LMB were checked (they flushed the stomach contents) every 2 weeks. They only found Tilapia in the stomach contents during the 2 weeks prior to the Talapia dying (when they got sluggish and LMB would have increased feeding activity) He said the contents were always primarily BG.

He's going to send the study to me once they complete writing it in a report format. I'll post it when I get it. It will also include stocking rates and the pond data so will be some interesting reading. As everyone knows there are LOTS of factors.

I would love to see the study. I'm sure there will be some other interest as well.

Great stuff Learnin!

He said the pond owners were spending over 10K per year on management, I would like to know the details on that LOL

I will be interested in the study results. Often people find what they are looking for and bias is often exhibited in studies. Not suggesting this one is such but have seen it often in the many years of reading studies. Here is one very counter intuitive study which was reported on in PB mag some time back. If you want to learn - get PB mag !

Tilapia – stealth predator - revisited

Several years ago, in The Cutting Edge an article appeared, named Tilapia – Stealth Predator which provided study results where the data presented clearly indicate rapid digestion of fish prey in the stomach and suggest strong stomach acids in the digestive process as the reason. The study titled Rapid Digestion of Fish Prey by the Highly Invasive 'Detritivore' Oreochromis Mossambicus by R. G. Doupe and M. J. Knott, Australian Centre for Tropical Freshwater Research, James Cook University, Queensland, Australia (November 2009) Journal of Fish Biology: 2010 v76 - p1019-1024 also suggested that Mozambique Tilapia is more likely a functional omnivore (channel catfish are omnivores) and supports the notion of it being, under some conditions a piscivore (fish eater). This issue revisits the conclusions contained in the study discussed in this prior Cutting Edge article.

Stockings in recreational ponds are often in conjunction with other forage sources like Bluegill, Golden Shiners and Shads so the relationship between these species and Tilapia is important. Tilapia are used in ponds mostly as yearly supplemental forage stocking because they have a high lethal low water temperature threshold around 10°C or about 50° F. Thus, in most of the U.S. range (other than Florida and south Texas) Tilapia don’t survive winter. Further Tilapia are generally thought to be herbivores and we assumed they did not prey much on other pond fishes. We knew they ate a few fish fry and eggs but mostly they ate plant material and have been described as a true detritivore, with the ability to assimilate free nonprotein amino acids directly from detritus. The study above contradicts this common knowledge. Here the prey fish were consumed but no prey fish were found in the stomachs of any size class of Mozambique Tilapia at one-hour post-consumption, and none were detected in the stomachs when examined at either 2, 4,6,8, 12 or 24-hours following consumption. It seems highly likely that all prey fish were digested within 1 hour of ingestion by Mozambique Tilapia.


Yes, there is always more to learn, and assumptions are sometimes incorrect, and studies have different results. So this issue we note a contrary study titled, Foraging in non-native environments: comparison of Nile Tilapia and three co-occurring native centrarchids in invaded coastal Mississippi watersheds by Mark S. Peterson, William T. Slack, Gretchen L. Waggy, Jeremy Finley, Christa M. Woodley and Melissa L. Partyka in Environ Biol Fish (2006) 76:283–301 DOI 10.1007/s10641-006-9033-4. Here the authors examined the diet of Nile Tilapia and bluegill, redear sunfish, and largemouth bass over a two-year period in coastal Mississippi. The study contained the following findings. Nile Tilapia diet was clearly separated from the three natives based on group-average linkage cluster analysis. Sequential two-way nested analysis of similarities indicated there was no seasonal effect, there was a moderate size class effect and most importantly, a strong species effect. Pairwise tests indicated species fed on different components of and locations within the environment, with bluegill, redear sunfish and largemouth bass having the most similar dietary components and Nile Tilapia having the most distinct. The stomach contents for these species provide an interesting comparison of their diets. Nile Tilapia examined for stomach contents ranged from 1/3rd to 17 inches, 590 fish, in 24 size classes. Frequently eaten prey types in all size classes were small prey like rotifers, nematodes hydrozoa, and bryozoa plus various insect stages and parts. Additionally, microcrustaceans like copepods, cladocera and ostracods were consumed quite frequently as were fish scales. The most frequent stomach items were amorphous debris, detritus, sand grains and mud clumps. This indicates that Nile Tilapia consume bottom sediment directly which reflects the diverse prey types in all fish, particularly the large individuals. Nile Tilapia had a distinct diet from all three native centrarchids. Nile Tilapia clearly foraged on lower trophic levels (mud, sand, bryozoans, nematodes, hydrozoans, and rotifers) whereas largemouth bass fed on larger invertebrates and fishes (insect parts, fish scales, unidentified fish, fish parts) at small sizes. Prey of bluegill (chironomids, calanoid copepods, insect parts, sand, cladocerans) and redear sunfish (chironomids, insect parts, sand, snails and mollusks) do not overlap to a great degree with Nile Tilapia. The main cause for this separation stems from the primary foraging of Nile Tilapia on the bottom resources whereas bluegill and redear sunfish forage more on pelagic species in addition to epi-benthic resources. The authors do note other studies showing some limited competition and interference with sportfish.

From these different studies and others on topic it is apparent that we don’t have all the answers about Tilapia. Depending on location there can be some competition between Tilapia and other pond species, but it appears only at a low level with tilapia being efficient generalist bottom foragers with great adaptability.


Here is more on a very complex subject in this thread.


Effects of Cover and Prey Size on Preferences of Juvenile
Largemouth
Bass for Blue Tilapias and Bluegills in Tanks !
HAROLD L. SCHRAMM, JR.
Department of Fisheries and Aquaculture
School of Forest Resources and Conservation
ALEXANDER V. ZALE
Florida Cooperative Fish and Wildlife Research Unit
School of Forest Resources and Conservation
University of Florida, Gainesville, Florida 32611
Abstract

The effects of vegetative cover and relative size of prey were tested on the forage preference of
juvenile largemouth bass Micropterus salmoides offered blue tilapias Tilapia aurea and bluegills
Lepomis macrochirus in laboratory electivity experiments. When offered forage at or near the
maximum consumable size in tanks without vegetative cover, largemouth bass preferred bluegills,
but consumed blue tilapias in the presence of vegetation. When offered forage smaller than the
maximum consumable size in tanks without vegetation, largemouth bass selected blue tilapias.
Differences between the forage species in body morphology and effective use of protective cover
apparently caused the changes in prey selection. Our results suggest blue tilapias may be a suitable
forage for largemouth bass, but that habitat characteristics
and relative size distributions of other
available forage may affect their use.

+1 to that! I've learned a lot since subscribing.

During late September and October the intestinal contents of the tilapia(TP) has consisted almost exclusively of dark brown mud organic like sediment. Little if any FA algae or delicate submerged plant like materials are now present due to the feeding activities of the TP.

My larger TP are still very happy to hit the pellets but the smaller ones were definitely shorter in numbers at the water inlet and high water outlet this evening. Not sure if they have pulled off a little to deeper water or if they have started to become snacks for the LMB. Seemed to be about 1/2 the normal population of what was present before the cooler weather started rolling through. Tuesday afternoon water temp 1' down was at 72.5.

Very interesting, Bill!

Are tilapia like carp, in the situation where there is little remaining food in the water column, they will stir up the bottom sediments to get at the interspersed organic content?

So, how do the Nile Tilapia and Blue Tilapia differ in stomach contents??

Question was I am not sure what is meant by little remaining food in the water column. I think TP manure creates more phytoplankton that results in more zooplankton. I have never did a study of how the zooplankton community changes with the activities of TP. It would be a very interesting small research study if I had more time. Just as a note - the zooplankton species composition changes weekly and monthly as the water temp, day length and phytoplankton composition changes. As the phytoplankton changes so goes the zooplankton populations. Both are very dynamic. Nutrient concentrations and water temperatures are big influencers.

TP, I think, provide excellent forage for 12" and longer LMB. The benefits of TP, I think, are much more muted for 1st year growth of 2" LMB fingerlings. I just base that on some of Swingle's age old research and a couple of anecdotes here where the effects either didn't seem to contribute to faster growth of 2" fingerlings than with BG and/or minnows and in one case the addition of MOZ TP in the initial year backfired and was detrimental. In that case, MOZ TP consumed FHM and grew to sizes that the 2" LMB could not keep up with. Seems like the pond owner also thought the TP may have consumed some of his LMB fingerlings. Lot's of forage for 2nd year and 3rd year LMB were produced in that pond but unfortunately, there were none of the sizes of LMB that could fully benefit from the TP resource.

With regard to escape speeds and probability of escape and so on. What I have found by reviewing the literature is that the realized consumption frequency curves for fusiform and laterally compressed prey can be normalized by reformatting the curves to proportionate weight instead of proportionate length. IOWs, when plotted versus proportionate weight, the curves lay one over the other with similar distributions. To be sure, proportionate weight is the primary variable of specific energy content but the probability to escape a predatory encounter must also be very sensitive to the variable of proportionate weight. In as much as this is true, fish of same weight have very similar probabilities of escape and have similar energy content. Still regardless of energy density, the primary factor affecting peak frequency of realized consumed sizes (presumably the most optimum forage size) is the probably of escape.

How much a forage fish weighs matters for the probability of surviving a predatory encounter. The heavier the prey fish ... the more likely it is that it will survive and the predator fail to consume it. Here just assuming that the health of the prey fish is good. TP in chilled water, it is safe to say, are compromised in the health category and thus are less capable of evading a predatory encounter. But under favorable conditions where one examines the difference between species on the basis of proportionate weight, the species which is heavier at the same length stands a better chance of surviving. Also prey fish in good condition (higher RW) are less vulnerable to predation than prey of the same species and same length that are in poorer condition. Generally, one should expect that MOZ TP will be heavier than BG of the same length. Enough so, for example, that a MOZ TP of 2 1/4" has a similar probability of escape as does a BG that is 2 5/8". Also MOZ TP can grow to 3" in 60 days where excellent growth for BG over the same span of time is 2". MOZ TP thus are better suited for larger LMB which tend to consume them at shorter lengths than they would consume BG.

I don't have lots of experience with TP but from my personal experience and observations with my first year stocking them here's what I think and what we did.

We stocked 10 lbs of 6-9" TP this year in the spring along with 50 2" LMB about a month later.

I think it is possible that the TP were large enough to consume the fingerlings on our initial stocking but that window was also very small. The growth rate of the LMB from fingerling stage was approx 1" every 16 days and have maintained that rate as best as I can tell up to now. Next check is Oct 19 to confirm our season growth weight and length.

As to which is easier for the LMB to catch between BG and TP - I'm leaning to BG being more subject to forage of the LMB than TP. I haven't been able to catch much in the way of BG in traps is where I'm leaning to on this. Visually not seeing many YoY in the pond either. Conversely, the TP were roaming in packs of like size fish all spring, summer and early fall. My observations from my inability to trap BG and lack of them visually in the pond. Would have better info if I seined or shocked but I haven't done either to date.

I did make it out to the pond today to feed the fish around noon as well as try to see populations of the small fish and species. It appears as though the small TP numbers have been halved with our cooler overnight temps over the past 7-10 days. Water temps are still in the lower 70's in the afternoon but likely dipping overnight. With the lower numbers of smaller TP I am not seeing more YoY BG however. The areas the TP were really visible just have fewer fish in them.

Interesting sidenote was that I was reaching out to one of the other PB members about his Titan Bass so see how he was doing on growth rates and in the discussion he mentioned that some of his fingerlings escaped and got into the TP grow out pond upstream. I don't know what other forage was in the pond with the TP but it sounds like the growth rates on those LMB were outstanding.

In reference to some of the older threads on TP I remember there was some discussion on what is a good stocking rate for the TP. One owner was concerned that if he stocked to many TP catchability rates would suffer but the responses in the thread were actually the opposite saying that a higher stocking rate of TP at 20lbs vs 5-10lbs per acre could actually improve catch rates.

I do wonder if there is something to the higher stocking rate of TP being validated by the two above conditions. I would assume the TP grow out pond had loads of TP in it and as a result the LMB used them as forage. Further validated by the older post(s) with stocking rates.

Again, my personal observations and conclusions here. I don't have lots of experience but thought I would relay what I suspect is happening at our place as well as some anecdotal info from other sources.

BD,

Bottomline.

Can you expand on your experience in the form of a recommendation for the initial year?

Your LMB have grown very, very, well. So one question would be, is this because you stocked TP? Or would the LMB have made similar growth without the TP this initial year? Another question might be, were they necessary to control FA this year? Could an alternative prey species that consumes FA (e.g. GSH) have provided sufficient control in this initial year? To be sure, there should be no regrets, but would you repeat this recipe with another pond?

There is no need for concern with regard to growth of the LMB thus far. That piece was fulfilled and was completed very successfully. Even so, it would be naïve to think that the TP had no effect that will reach into next year. So as we approach the winter period it is worth asking if the TP have better prepared you for the forage needs that will take place after the TP die off. In your opinion, did TP fulfill the promise of increasing survival of YOY BG? If not, what are your thoughts on the reason?

All things considered, would you recommend to others to stock TP as part of the initial year stocking?

Here are some thoughts for this before BD replies.

1. He says the stocked TP were large enough to MAYBE eat some of the stocker 2" LMB. If that did happen then IMO it reduced the density of LMB stockers that in turn resulted in more food available for the surviving LMB that allowed them to grow better at a rate considered near maximum for LMB at this geographical location.

2. If YOY TP are better able to elude predation compared to BG, this escapement factor is IMO compensated for later when the YOY TP are easy captured in cooler water compared to small BG who in cooler water better more agile swimmers than the struggling edible sized TP. We have seen numerous species of predator fish die in fall with oversized TP stuck in their throat.

3. I don't think GSH are very affective or efficient at controlling FA. I have a 0.3ac pond near me that has a strong population of GSH due to the SMB numbers have diminished and the YP are not very effective at eating healthy 3"+ GSH that serve as brood stock. The owner has been increasing his purchase of TP each year to now 7lbs as 23 TP to control the FA. I think the FA that has been reportedly eaten by GSH has been FA in stomachs as mainly filaments consumed incidentally by the GSH as they are wanting to eat mainly the myriad of invertebrate that are living in and among the clumps of FA. IMO TP are firstly primarily vegetarians and detritovores and when those preferred food items are lacking their hunger causes them to resort to eating whatever animal foods they are able to capture.

I'm in the undecided category for recommending TP in 1st year which would likely mean I could share my experience and that's about it. I could be completely wrong on my lack of YoY BG from tapping, I just wasn't able to locate much of a qty of them in the sets I made.



We did have a little bit of FA started in the pond before I stocked the TP. I had zero FA floating mats in the pond this year though we would see a little bit of it on rocks or submerged vegetation and trees in the water.
Our stocking of TP was to both keep the FA from overwhelming the pond (had family stuff going on at the property with dad's passing), everything I read was they were a great forage option and one of their key benefits was that they outproduced BG which ultimately saved the BG as forage for later in the year.
*** Perhaps the YoY TP have pushed the YoY BG to a different area of the pond or habitat and they are present but I'm not seeing them.
*** Perhaps my stocking rate wasn't high enough to provide a dense enough forage base for the LMB to really key in on them.
*** Perhaps my traps were just not the right style for the YoY BG.
*** It is possible that you are correct that LMB are more effective at catching the TP once the LMB get to the 12"+ size and they pick off smaller TP as their optimal forage.
*** Very likely that some of the growth we saw in the LMB is attributable to the TP being present. I can't imagine a scenario where none of the YoY TP were eaten. As they are seemingly shorter in numbers now I can only guess that the LMB are starting to pick them off with the cooler fall temps.

Sadly, my perhaps above won't be answered this year. Once the TP are gone from winterkill I suspect that the fish will be in deeper water which will also prevent visual efforts to locate and I assume that trapping them in cool temps would have the same results as stocking them at low temps ultimately leading to death of trapped BG. My suspicions, assumptions, and guesses left me with a conclusion that I would need to supplement forage to make sure there were no hungry mouths to feed over the winter. Hopefully giving the fish time to correct any issue with a shortage of YoY BG before it manifests itself with low RWs.


I have no regrets in trying to find ways to "push" the fish this year on growth. I think if a pond owner is going to push LMB growth he or she is going to have to make calls along the way based on what the pond and the fish are telling them. In my initial samples of the fish I was seeing an avg RW of 162% (3 fish Aug 3rd - 12th). Those RW's changed to an avg of 124% (4 fish Sept 21st - 23rd). In the second set all the fish seemed to generally have the same appearance of thick back, filled out tail and a little thin on the belly. My call based on the notable reduction in RWs between the above dates and visual condition of the fish was to bump the forage. Reposted a pic of the fish from previous that needs to eat a supersized value meal!


I have no proof to offer here other that what I've stated above. My personal belief is that the TP didn't fulfill the promise of increasing survival of YoY BG. The only thing that makes sense to me is that the BG were easier to prey on. There could be several reasons for this however. One that I have spent time pondering is - If the YoY BG and the TP didn't occupy the same habitat then the YoY BG were displaced into areas that may have made them easier to prey upon as the YoY TP were at all of the complex structure, and shallow water riprap (inlet and outlet).

My feeling of lack of successful use isn't in anyway changing my plan to use them in 2025. In fact I'm looking forward to trying them again next year at the same 10lb rate and size if there is no LMB spawn. If there is a LMB spawn I'll likely double the TP to 20lbs. I'd love to see if there is any difference with the amounts of TP produced through the year. If it's less production I would guess that there's been increased consumption which is a good thing.

Glad to see you say this. TP will contribute much more to the consumption of prey next year. Production includes mortality by consumption. This will be at least partially evident in the growth of your LMB (which will be blend of consumption of all available consumable forage).