Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Stocking Tilapia for FA

I stocked 30 pounds of brooder size Mozambique Tilapia to my 1.5 to 2 acre pond today for Algae control and to assist with feeding intermediate Bluegill. The pond is about 4 feet low. 75% of the pond is 4 ft. or shallower so there is a significant amount. How long after stocking before I should expect to see visible results?

I have treated 3 times with Cutrine Plus so it has not totally overtaken the pond but is still thick.

Using TP to control the algae is a learning curve.
It is always best to write all the year's following information down in a booklet or on your phone notepad. .
1. note as best as possible how much algae is present. It is always best to remove and not just kill some algae before introducing TP. Removing the algae removes the incorporated nutrients in the algae biomass. IMO pond mananagement is in reality nutrient management. Nutrients accumulated in the pond causes the need for TP because the accumulated unused nutrients are what is feeding the algae problem.
2. each year note how many TP and the poundage that were stocked.
3. as the season progresses note the amount of algae still present as the season progresses. Is it less? Is it more? Is it the same? How fast the algae becomes noticably less is VERY important information.

Each TP can daily only eat just so much similar to you at the food buffet. If the algae is not undercontrol and noticably less after TP have been in the pond for 6-7 weeks then IMO you did not put enough TP in the pond. If algae is basically gone after 5-6 weeks then you could add fewer next year. If algae is not basically gone in 8-10 weeks then you need to add more next year.

What is your current water temperature a few feet below the surface? How big are your stockers? They look to be about 6" long?

If so, then most of them are probably sexually mature and should start spawning once they are happy and acclimated to your pond.

It is hard to measure accurately, but I believe some of our tilapia stocking pond owners think that it is the abundant spawn from the stockers that really cleans up the FA. I don't know how fast the tilapia fry will grow and become voracious eaters in your pond. But if they do thrive and grow quickly, then the stockers plus their descendants might be enough to get on top of the FA on Bill's 8-10 week timeline.

Even if your tilapia stocking does not eradicate the FA in your pond, then I suspect just breaking even at the current infestation would still be a much better result that some of the northern Oklahoma ponds that I have observed where the FA increases right on through August!

Were you able to pick your delivery date, or was the date somewhat fixed by your supplier? I would keep good records and try to get the tilapia into the pond as early as possible without putting them into cold enough water to induce excess mortality.

Good luck on your FA control project.

P.S. Do you have any plans to get tilapia OUT of the pond in the fall? As Bill says, the tilapia are just part of your "nutrient management" system. I believe if you remove a significant proportion of the tilapia each year, then you will also be removing some nutrients.

IHMO, you didn't stock enough. Time will tell. Here, in Northern Indiana, I have found that ALL visible algae has to be killed 5-7 days pre or post stocking of Tilapia, and the best size Tilapia to stock are 4-9 per pound. If 40 pounds per surface acre isn't stocked, or the the algae isn't killed (removed like Bill said is best) then it's like they weren't stocked at all.

Don't think "Oh, I don't have to kill it, I'll just stock more per acre." Bob Lusk commented that they stocked 100#/acre without killing the algae and they didn't do anything, and I duplicated that one year with the same results.

Cutrine Plus liquid for water <24" deep, Cutrine Plus granules for deeper water is what I recommend to all our customers. Follow application instructions on the container or bag.

Stocking 1#+ adults doesn't get the results that stocking smaller fish do, and if the Tilapia are food grade and not 50/50 male/female then you will not see the algae control either. The 90-10 food grade sex mix really doesn't work well at all.

We also got bit one year by stocking the Tilapia in water that was in the low 60°F range. A prolonged cold front rolled in, water temps dropped to the low 50's and we replaced a LOT of dead Tilapia. Now we won't stock Tilapia until water temps at 2' water depth are 70°F.

Learnin,

I was previously just typing up some more ideas for you, based solely upon my "book learning" from Pond Boss. Esshup actually gets paid to manage the exact type of project you are posting about - so definitely heed his advice!

esshup (and others),

Is your advice essentially to stock as many tilapia mouths as you can afford? For example, if your supplier offers 3-4", buy more of those instead of the 5-6" size?

Is there a problem with slow-growers buying the smaller fish? Or are those fish just from the last spawn of the previous year?

Finally, your anecdote about the tilapia kill sounds like the perfectly bad conditions of transport stress and then cold stress hitting the fish at the same time. Does anyone have an estimate about how long the transport stress would last for tilapia? I am just asking to see if your weather forecast predicted a cold front 6 days in the future, would that be enough for your tilapia to survive the dip in temperatures, or would it be better to wait another week? (And maybe run into supplier schedule troubles etc.)

Transport stress was not an issue. It was the cold temps and the supplier selling "Blue Tilapia" but furnishing hybrids that wouldn't survive water temps in the low 60°F range. We have since switched suppliers. Talking to other retailers in the area, they had the same issues.........

It's always a juggling match between supply and timing of stocking. Some suppliers "get it" and will reduce feed to slow down growth to ensure the correct sized fish are available at the correct time, others don't care.

One retailer that I will not name specifically requests food fish grade and not 50/50 M/F so they are called back to treat algae in the ponds........... FWIW it's nobody that I have ever seen on the PB forum.

esshup,

Thanks for the follow-up post. Tons of good information in there!

Thanks everyone for the valuable information.

I'm a documentation nerd so appreciate the advice.

I'm using an excel spreadsheet for calculating pounds/species of fish added and removed. The pounds of fish food I feed per day, and weather factors. (Rain/temp) as well as the pond water level and water temperatures.

I use a drone to document the approximate coverage of Algae and observation of fish activity.

I purchased the the TP from Harbin's in Kansas and he told me they were brooders. esshup, I agree that I did not stock enough, but at $18 per pound that's all my budget could handle. Sounds like I may have been better off to invest in chemical. I still have enough Cutrine Plus to treat the pond at least one more time so I will do that ASAP.

I am stocking them for Algae control and for supplemental feeding for my intermediate BG. Mr. Lusk said they are excellent for that. So hopefully there will be some measurable benefit from my investment.


Rod

The pond temperature was 72 degrees at 3 feet on 4/23.

The TP in the picture was one of the largest ones, most were about 4 to 6 inches so I would say the stocking size was probably in the 4-9 per pound range.

Everything I've read and heard matches what you said, it's the offspring that will eat the FA.

I plan on seining to remove them, as well as CC, YBH and GSF.

I recorded drone footage last week, there's a LMB on a nest about 25 seconds into the video on the right side of the video. I think it's a male, it appears to be much smaller than most that I've caught.

That's a perfect size to stock, and that water temp is good. I'd whack back as much of the FA as you could. If you don't have one, buy or make a secchi disc. Water clarity should be one of your data points. FA will grow on the pond bottom 18"-24" deeper than the secchi disc reading. Underwater vascular plants will sequester nutrients and also help reduce FA growth.

Harbins is good to deal with. They also have a facility E of OK City.

How far away are you from Midwest City? I might be swinging down to see a friend there this summer.

I'm 2 hours North of Midwest City. PM me if you decide to come this way, I'd be glad to offer you a good home cooked meal for some expert advice. I've got fresh farm raised pork or beef. I also have plenty of fish in the freezer from some recent trips.

Thanks for the reminder on the Secchi disc, I have one and have not used it this spring. I'll get a reading this weekend and add a column for that in my sheet.

I have Southern Naiad and there was some American Pondweed but the area where it was growing is dry land due to the lack of pond filling type rains. We've had some rain but it's just coming slow and steady so soaks in.

If you do come this way, hit me up. It would be a pleasure to meet you.

I'm treating with Cutrine Plus, from what I've read due to the volume of FA that I have I don't want to treat the whole 2 acres because it may cause oxygen depletion and a fish kill. What percentage should I treat and at what intervals should I treat it.

Also considering adding pond dye after the BG move off the beds since I have heard it can inhibit spawning. Would the dye also have the potential to cause a fish kill due to the dying FA?

Not being a smart a.. but what does the label say?

FWIW, AQUATIC USES:
Waters treated with this product may be hazardous to aquatic organisms. Treatment of aquatic
weeds and algae can result in oxygen loss from decomposition of dead biomass. This oxygen loss
can cause fish and invertebrate suffocation. To minimize this hazard, do not treat more than 1/2 of
the water body (excluding water infrastructure and constructed conveyances such as drainage
canals, ditches and pipelines or intakes and aqueducts for drinking water or irrigation use) to avoid
depletion of oxygen due to decaying vegetation. Wait at least 14 days between treatments. Begin
treatment along the shore and proceed outwards in bands to allow fish to move into untreated areas.
Application of algaecides to high density blooms of cyanobacteria can result in the release of
intracellular contents into the water. Some of these intracellular compounds are known mammalian
hepato- and nervous system toxins. Therefore, to minimize the risk of toxin leakage, manage
cyanobacteria effectively in order to avoid applying this product when blooms of toxin-producing
cyanobacteria are present at high density. In situations where rapidly reproducing toxic algal species
pose a public health threat to drinking or recreational water resources, applicators must receive
authorization from applicable state, local or tribal water resources authorities to apply copper at
intervals shorter than 14 days should the circumstance demand.

Certain water conditions including low pH (≤6.5) low dissolved organic carbon (DOC) levels (3.0
mg/L or lower), and "soft" waters (i.e., alkalinity less than 50 mg/L), increases the potential acute
toxicity to non-target aquatic organisms. The application rates on this label are appropriate for water
with pH values >6.5, DOC levels >3.0 mg/L, and alkalinity greater than 50 mg/L. Avoid treating
waters with pH values <6.5, DOC levels >3.0, and alkalinity less than 50 ppm (e.g., soft or acid
waters), as trout and other sensitive species of fish may be killed under such conditions if present.

Dye *might* kill some FA, depending on how dense you dye it and the water clarity now. Check with a secchi disc pre/post application. Plants/algae can grow 18"-24" deeper than the secchi disc reading. If I am not feeding the fish in the pond, I don't like to use dye.

If there are underwater plants in the pond, killing the algae and dye *could* kill some of the plants due to the increased phytoplankton bloom after the FA is gone, because of less light penetration, and dye will make that worse. Like we say here, "It all depends" (on multiple factors).

Thanks esshup 🤦‍♂️ I read after asking.

Secchi reading was 5 feet 2 inches today.

All of the artificial trees are submersed accept for the purple one.
The 2 by the dam are in 6 feet of water.

In the last overhead video what is in the water at about .48? Black?
jim

My "expert" analysis of your last drone footage - time for some darn rain!

That was a Cormorant.
I promptly chased him off when I finished my video.
Drones are great for scaring them.

Bill I agree with your statement "pond management is in reality nutrient management" and have been thinking about that. I have fenced cattle out, and stopped fertilizing all ground I own within the watershed. I don't think that there is too much other ground in the watershed that is fertilized. Most of it that I don't own is native grass. There are several ponds around me that don't have the amount of FA that I do though.

Do you have any idea how long would it take for measures like I have taken to work?
What else would you recommend for nutrient control?

Is it possible that since the pond is 4 feet low and reduced by at least 1/2 acre (so condensing nutrients) and most of it is less than 5 feet deep is the major contributor?