I'm hoping someone can point me towards some information about the catchability of bass in ponds that are adequately stocked with Tilapia.

The owner of the pond I fish stocked Tilapia last year, but at less than 5lbs per acre. I'm trying to convince him to stock more this year, since the tilapia last year only put a small dent in the FA and grass and we didn't see much improvement in the bass.

His concern is that a lot of Tilapia will make the bass impossible to catch, but I remember reading a study that showed the opposite. It said that adequate forage made the bass active for longer periods and actually improved catch rates. Anyone have a link or know of any articles on the subject? Or can anyone share their own experience with catch rates before and after stocking Tilapia at a higher rate, such as 20lbs+ per acre?

Thanks

LMB do just fine with tilapia @ 20 lbs per acre. Plenty of people do that. You may need to watch your carrying capacity. Tilapia are no different than other forage fish wrt LMB feeding. That assumes they do not overwinter in the pond. That would change all aspects of this post.

To add to ewest's post above, the only "danger" to carrying capacity in a pond where tilapia death is annual would be similar to feeding pellets bluegill heavily...once the total number of game fish weight is increased in the pond by the "feeder" tilapia, not continuing to stock tilapia anually will leave a lot of hungry mouths with no food to find.

--------------------------------------------------------------------------

ewest note

I agree with Rex's point about keeping up forage (fish and or feed) as it is not wise to jerk the food chain out from under the fish. Just be sure to keep an eye on water quality (carrying capacity) as you ramp up the engine that is your pond. Same would go for any activity (stocking , feeding , supp forage - of all kinds or fertilization) that ramps up production. The faster you run an engine the more you need to watch for possible problems ( it is called management). FWIW 20 lbs of tilapia per acre is a common amount in the south in many ponds. Some less , some more , depending on the situation. It will not effect LMB feeding methods / amounts but will improve their condition.

ETB, there's no catchability problem that I've ever experienced. If the pond is around Rowlett, you should get at least 6 or 7 months use out of them. Not sure what grass you're talking about, but if the pond can handle the load, 20 pounds per acre should handle the FA. Mozambique Tilapia are a very good choice for this area.

Thanks for your replies everyone. The pond is near Canton, TX. Tilapia surviving over the winter shouldn't be a problem.

No, but the Tilapia walking to Dairy Palace may be.

We stock tilapia in about 20 of our 45 ponds and lakes. Many of those are in and around east Texas and a few around the Canton area. We seldom stock 20 lbs to the acre, but more likely 10 lbs to the acre. I would love to stock 20 lbs to the acre, but when you are stocking 30 acre lakes; in can get expensive real quick. We see no difference in catch ability in lakes where this is the case. The severity of the FA will help determine how many to the acre you need to stock, but 5 to the acre is probably not going to put a dent in a pond, unless you have a pond that has very little FA to begin with. I think 20 lbs to the acre is a good amount. If the lake or pond is covered; 20 lbs to the acre may not cover it. I know some properties that stock 30 to 40 lbs the acre, but that is more for forage than FA control. I would start with 15 to 20 lbs and see how it does. Once you get it under control you maybe able to cut back to 10 to 15 an acre.

Steve, thanks for your response - tilapia stocking rates in N.E. Texas ponds - it all depends, as you say.
First stocking years ago 5 lbs/acre didn't put a dent in FA - 10 lbs works for me under normal conditions - 15 to 20 lbs per acre when bad as last year.

No difference in LMB catch rate with or w/o tilapia except seasonal cold water effect - only time no tilapia present.
George

EastTexasBassin my property in Wills Point is only about 15 miles away from you and I had 95 lbs of Tilapia in my 4 acre pond last summer. The tilapia did well, but did not dent the aquatic vegetation as much as I would have liked, so I may up the tilapia numbers this year and see what happens.

I bought my first batch of tilapia last May. They were from the Northeast Texas Farmers Co-op in Canton. The Northeast Texas Farmers Co-op tilapia were kind of small and did not seem very good quality. The young guy bagging them took forever, seemed like he hated his job, and I think stressed the fish. A month later I bought my second batch of tilapia from Overton's Fisheries. The Overton's tilapia were big, healthy, active, much better quality. Overton's delivered them to my pond.

We got our Tilapia from Overtons last year. We made the drive and picked them up. They were kinda small, they said someone had just bought all of the larger ones. We were planning on trying the co-op this year, thanks for the info.

wow that's a bit surprising....
unless it was towards the end of the buying season
what month did you buy your Overton's tilapia?

It was very late in the season, early July. We won't be waiting that long this year.

ETB, The Tilapia fry/Fingerlings are easily eaten by young fish and few Tilaia offspring reaching 4+ inches can't be easily captured by LMB until becoming lethargic, when the LMB will gorge on them and wipe out the edible size tilapia in a couple days time. Since the Tilapia are not an easy, filling prey throughout the year for larger LMB, catchability wouldn't be affected till the tilapia lethargy phase occurs, and as said, only lasts a couple days.

FWIW, in trophy Bass ponds SEPM and some other managers stock Tilapia in rates at and eceeding 100 pounds per surface acre to not only be a huge forage supplement, but also to keep aquatic vegetation stripped to allow bass to eat easily and grow. I have yet to see or hear an "upper limit" in a pond where the tilapia will die annually. Unfortunately, there is little, if any scientific studies on Tilapia in sportfishing ponds...lots on monoculture and polyculture aquaculture ressearch related to growing food fish only, where carrying capacities for growth to harvest size exceed 11,000 pounds of fish per acre of water...a capacity a "recreational pond" will never reach without .



Edit: Corrected typo on LMB capturing 4"+ tilapia from "can" to "can't easily" and more clarification...

I'd like to chime in here. I was initially worried about what Rex presented in his first post in this thread. I thought we'd stock tilapia into a bass-heavy pond, they would reproduce prolifically, bass would grow, tilapia would die in the fall and the pond would be out of food.
In fact, that's not what happens at all. As long as bluegill are present in that pond/lake, tilapia increase survival rates of baby bluegill. Think about it mathematically. Tilapia outproduct the bluegills. Say your pond produces 100,000 tilapia and 50,000 baby bluegills over a three month period. What's the statistical chance that those bluegill will be eaten? The odds shift and bluegill survival rises. Over the entire year, baby bluegill have the opportunity to thrive with lower odds of being eaten than if there were no tilapia in the lake. As the season progresses and we get into fall, tilapia become sluggish. Bass gorge themselves on small tilapia and the bigger ones die off. Left behind? Thousands of small bluegill which were able to survive because of the big numbers of tilapia in that pond. So, you have good odds of more forage fish going into winter than if you hadn't stocked tilapia in the first place.

Back to the original question. I like the premise. If a lake has plentiful food and bass have lots of options as what to eat, they eat more freely. I think that's the concept that's being asked.

I've been studying intently "catch rates" and people tend to think it's mostly related to hunger. Other folks think bass become hook shy when too much fishing pressure is on a fishery. Still, others believe that when we catch and remove bass, we are basically harvesting the most aggressive fish in the lake and altering the evolution of that fishery into a passive one, genetically.

It makes sense to me that a lake teeming with baitfish, even if those forage fish stocks are seasonal, could certainly impact the behavior of the nearby predator fish population. It makes sense to me that they could be aggressively feeding when that food is availabile. If so, it makes me think that catch rates should rise.

I agree with Bob's "chime in" completely...My point was... not continuing to stock Tilapia annually after raising (non tilapia) fish biomass, stops all the increases gained in Bob's post above and the "carrying capacity" falls back to "pre-tilapia" levels through starvation/predation somewhere in te food chain.

Never a good idea to jerk the food chain out from under the fish ! Once you start augmentation ( tilapia , pellets , fert program etc )you need to keep it up or be ready greatly reduce the number/weight/amount of predator fish.

Rex,

Your experience has been that adult LMB can't easily capture (feed effeciently) on 4"+ tilapia until they become sluggish or lethargic in the falling water temps in the fall or winter?

The tilapia will die 100% of winters in Canton.

In my pond, that doesn't have a lot of fish hiding cover, I've seen packs of 12"-14" LMB chase 4" Tilapia and the Tilapia actually "swim" up on shore to get away from the LMB. The pack will wait until they flop back into the water..... While it may not be easy, or effecient, if a limited amount of small Tilapia are stocked, they can get wiped out in a hurry and will preclude a sufficient breeding population for the pond.

Boy, have things changed - I go back to the days when Lusk thought tilapia stocking was not a good idea...

I believe we have to be very careful in giving tilapia advice, unless advice is qualified for southern or northern waters...
BIG differnce!
G/

George, I agree. Same with initial stocking advice for LMB/BG ponds. Big difference between N and S ponds in regards to time frame of stocking.

At this point I agree with esshup about 14"+ bass frequently eating 4" tilapia and will disagree with Rex until I see some stocking and survival data. I like esshup have seen 13"-14" bass and sometines groups of bass attack kill or eat newly stocked tilapia that were 5"-7" long. What do you think would happen with a 4"-5" tilapia that is newly stocked into a pond with a fair number of 17"-19" hungry LMB?? If there is plenty of food items in the pond when smaller 4"-6" tilapia are stocked, then the chances of survival will be better IMO.

It would be very interesting to see a study where 4"-6" tilapia were stocked into a LMbass pond and look at the survival rate of those tilapia stockers after 3 to 4 weeks. Rex has told me that tilapia are quick and keen at escaping bass, but I wonder how quick a tilapia would be when it is focused on eating some filamentous algae or with its snout sucking up some algae - bacteria laden sediment.

LMB (like many fish species) are incredibly adapted and infused with amazing innate survival abilities. Note I did not say smart. Look at this and think about the intricacies of optimal-foraging theory. Note how this fits into the points made above by Bob , Bill and others. FYI 100mm = 4 inches +-.



Transactions o f the•4rnerican Fisheries Society 114:725-731, 1985
¸ Copyright by the American Fisheries Society 1985


Effects of Cover and Prey Size on Preferences of Juvenile
Largemouth Bass for Blue Tilapias and Bluegills in Tanks!

HAROLD L. SCHRAMM, JR. and
ALEXANDER V. ZALE

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. W hen 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. W hen 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 . ur 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.


When offered forage at or near the maximum
consumable size in tanks without vegetative cover,
largemouth bass consumed more bluegills than
blue tilapias in 11 of 12 trials (Table 1). When
offered forage of the same relative size in tanks
with vegetation, largemouth bass consumed more
blue tilapias than bluegills in all 8 trials (Table
1). In trials with forage smaller than the maximum
consumable size in tanks without vegetation,
largemouth bass consumed more blue tilapias
than bluegills in 8 of 10 trials (Table 1).
Selection was significantly different from random
in all three cases.
Relationships between total length and body
depth indicated bluegills larger than 45 mm TL
were deeper bodied than blue tilapias of comparable
length; at total lengths less than 45 mm,
blue tilapias were deeper bodied than bluegills
(Fig. 1). Slopes of the regression lines were significantly
different. Blue tilapias consistently
weighed more than bluegills of equivalent total length or body depth (Fig. 1

In the absence of vegetative cover, juvenile
largemouth bass consumed blue tilapias rather
than bluegills when both species were smaller
than the maximum consumable size, but reversed
their preference when prey were at or near
the maximum consumable limit. We suggest this
reversal is consistent with optimal-foraging theory
(Schoener 1971; Pyke et al. 1977). Within
each of these trials, body depths of both forage
species were equivalent and interspecific differences
in total lengths were relatively small or
absent (Table 1). However, blue tilapias consistently
weighed more than bluegills of equivalent
body depth or length. This difference in depth or
length-specific weight was attributable to the
more robust morphology of blue tilapia; blue tilapias
are conspicuously thicker bodied and have
a greater girth than bluegills of equivalent length
or body depth. When offered easily ingestable
forage, well below the maximum consumable size,
largemouth bass selected the heavier, and therefore
more energetically valuable, prey item (blue
tilapia). Conversely, when offered forage at or
near the maximum consumable size, for which
handling costs are high (Werner 1974), largemouth
bass selected the more laterally compressed
prey (bluegill). Thinner-bodied prey may
be ingested more efficiently because of reduced
girth or defensive struggle capabilities, or may
have been selected simply because largemouth
bass perceived them to be smaller, despite their
body depth. Largemouth bass prefer forage
smaller than the maximum consumable size
(Tarrant 1960; Wright 1970; Shaftand and Pestrak
1984).
Because the largemouth bass in experiment 3
(forage smaller than the maximum consumable
size) were larger than the largemouth bass in experiment
1 (forage at or near the maximum consumable
limit), differences in predator size may
have affected prey selection. However, both
groups of largemouth bass were of a size considered
to be predominantly piscivorous (Carlander
1977) and no relationship between predator size
and prey selection within each experiment was
evident (Table 1). We consider relative prey size
to be a more likely explanation of the observed
reversal in prey selection.




When offered easily ingestable
forage, well below the maximum consumable size,
largemouth bass selected the heavier, and therefore
more energetically valuable, prey item (blue
tilapia). Conversely, when offered forage at or
near the maximum consumable size, for which
handling costs are high (Werner 1974), largemouth
bass selected the more laterally compressed
prey (bluegill). Thinner-bodied prey may
be ingested more efficiently because of reduced
girth or defensive struggle capabilities, or may
have been selected simply because largemouth
bass perceived them to be smaller, despite their
body depth. Largemouth bass prefer forage
smaller than the maximum consumable size
(Tarrant 1960; Wright 1970; Shaftand and Pestrak
1984).

The increased consumption of blue tilapias by
largemouth bass in the vegetated tanks suggest
that blue tilapias did not use vegetative cover to
escape predation as effectively as bluegills.

Our findings indicate habitat characteristics
may affect relative use of blue tilapia by largemouth
bass. Furthermore, the consumption of
blue tilapia may affect the predator-prey dynamics
of other forage species. High densities and
stunting ofbluegills are commonly attributed to
reduced vulnerability to predation by piscivores
when aquatic vegetation is abundant. Juvenile
largemouth bass selectively foraging on blue tilapias
when vegetation is present may further
reduce predation on bluegills. Shaftand et al.
(1983) found an increase in the abundance of
small bluegills in a vegetated lake containing
largemouth bass and an expanding population of
blue tilapias.

A couple things stand out to me here.

1) Where does science draw the line dividing a reflexive action/ adapted ability/ learned response, and an actual, very basic thought process, where fish are concerned? I've mentioned this here before, but I still struggle to place every observed behaviour under the category of instinct, or adaptive behaviour rather than something more profound?

2) This particular study appears to reinforce a strong belief of my own: adding Tilapia to a traditional, LMB heavy, trophy BG pond may not be in your best interests if continued management of trophy BG is the goal, especially in the presence of vegetation.

sprkplug:

I agree about your statement on introducing Tilapia into a pond where you're managing for trophy BG. What we did last year was in such a pond we stocked Tilapia that were predominately Male at the rate of 40# per surface acre. Filamentous Algae was controlled, and we didn't seen a larger recruitment of YOY BG from last year vs. the previous years. The pond will get the same treatment this year.

That is a common aquaculture method for raising food sized tilapia in the shortest period - all males.

All supplemental stocking into a pond with adult predators is a size/numbers game. Habituation helps reduce the risk of over/under stocking. There are threads here with the science on the subject.

Eric - Good study; thanks a lot for finding and posting it. Good data. I used the high and low factors (bass length/tilapia length) of maximum consumable size of tilapia that bass were fed in the study to calculate the lengths of tilapia that several sizes of LM bass were able to eat. Bass 16" long would consume 4.4"-5.5" tilapia, 18" bass would eat 5.0"-6.6" tilapia and 20" bass would eat 5.5"-7.4" tilapia. Habitat/cover, size of LMbass and other forage species evidently play a role in how well newly stocked tilapia will survive after stocked into a pond with adult bass.

I knew you would look at the data so I did not offer an opinion in my post above. I agree.

I find that bluegill are the top predators of YOY tilapia. Seeing one that is between 2 and 6 inches is very rare.

Dave,

Can you explain this a bit further?

Is it possible that the "maximum consumable size" for the blue tilapia was over-estimated in the tests therefore making them less desirable at that size?

No chance that the fish were miss measured in that study. This type study is subject to rigorous standards and test checks and is then peer reviewed. Plus this one is by two of the top Fisheries Science guys out there. I sometimes disagree with some aspects of this type study and can find conclusions or assumptions I disagree with. However I have never seen one where I thought the data was wrong or the methods used questionable.

Steve, when I see the parent guarding the fry,(usually around weeds) there are a lot of small BG hanging very close. When they get released from the mouth, at least one BG gets a snack. Very few make it to maturity. However, the BG do quite well.

BG are also the biggest eaters of LMB and BG fry. Its a numbers thing. Lots of hungry BG mouths.

Absolutely. I've witnessed my BG foraging in the shallows for fry and small yoy fish many times. I think the predatory nature of larger BG is possibly under-utilized, from a management perspective.

Eric,
I wasn't thinking the fish were mis-measured.

How is it determined what the "maximum consumable size" tilapia is for a 12 inch bass or a 16 inch bass? Is this done by some sort of scientific method?

As I know it, maximum consuable size of forage for a predator fish that swallows its food whole, is to measure the gape of the predator's mouth. FYI - the gape is slightly greater horizontal compared to the vertical measurement.

In this case that was not a measurment but a known (from prior work by other scientists) like RWs for example. That was used to decide what size forage was to be stocked for both BG and tilapia. It is based on gape size or the predators used. It incorporates also the width of the prey as well as max gape

Like with most posts when things have been explained and repeated over and over in posts, I tend to qualify my comments/advice in my mind and not in the post...I do not deal with stocking southern waters, because I deal with the more cold tolerant Pure Strain of Blue Tilapia and only stock/advise in more northern climates......

As for 4" tilapia easily avoiding LMB in a pond, I am referring to offspring of stocked Blue tilapia that have reached the 4" class....These tilapia grew to that size due to rapid growth and avoiding predation from their quickness..not so much from just getting "lucky". While as Scott said, prey will get chased up onto banks occasionally, and the surviving offspring percentage reaching and exceeding 4" will be low...late season catches of fish that are clearly too small to have been original stockers is my anecdotal evidence of fry survival to adulthood...

Again, these numbers may be low, possibly even insignificant. I have only seen lone 14'+ LMB stalk and attack 4-6" Blues and wind up missing, looking around wondering what happened to their prey....

Do you find bass working as a group, almost like a wild pack of dogs, when trying to catch tilapia?

I saw this behavior at a lake in east Texas about 3 months ago. This owner has nursery ponds above the big lake with a pipe connecting the two. I arrived two days after one of the releases of tilpaia that were raised in the nursery ponds in October and saw at least ten 3 to 6lb bass herding tilapia in a corner of the lake near the pipe that flushed the tilapia in the lake to begin with. I watched for almost an hour. About every 2 to 3 minutes one of the bass would make a run for a tilapia; while the other bass kept a perimeter around the tilapia. I thought this might be an isolated case.

I've seen 'wolfpacks' of hungry Bass herding small fish into the shallows many times. And that was with BG as the forage. And yes, every so often one would make a strafing run while the rest maintained the perimeter.

Ive seen a snook hit a tilpia so hard I heard a thud sound.
prob a 6" tilapia...
Snook are a bit faster than LMB though...

I'm sure schools of bass are commonplace...I just haven't had the pleasure to stick around a pond long enough to see it...lol

LMB waiting at the stocking location is common. That is why you habituate them with a net or enclosure. Thick cover in the area can also help.

Me too, I could watch them all day. Everytime we get questions on the forum about stunted and skinny bass I see them in my minds eye, corralling and eating those BG day after day after day, until there's just not much left. Really hard to overcome that degree of predation by building the forage base alone.