View Full Version : Blue tilapia growth sampling

08-28-2010, 07:40 AM
Last night my wife and I transferred half of our blue tilapia fry out to the greenhouse. This sampling is rough estimates no exact counts were done other than the total number of fish transferred. This amount was from one 5-6 inch female brood fish.
As I said roughly half were transferred and the total count was 284. So that puts her total spawn somewhere between 500 and 700 fry. I will update an accurate count when I transfer the other 50%. These fry were 30 days old last night when we transferred them. I am excellent with measurements without a ruler. Carpenter. Percentages are a rough estimate based on my wife and my estimates. I know this is not very scientific, but it is darn close.

20% of fry were +/- 2.25 inches
60% of fry were +/- 1.5 inches
20% of fry were +/- 1 inch

I will update from time to time as growth progresses. Thought some of you might be interested. I am very happy with the results considering the current conditions. No auto feeder. These fry only got fed in the morning, then several times in the evenings, and multiple times during the day on the weekends. They were kept for the first 20 days in a 75 gallon aquarium, then separated into two 75 gallon aquariums for the next 10 days. Needless to say by day 30 they were getting rather cramped (IMO) Feed was Purina Aquamax.

I fully cycled the greenhouse tanks, and if no water quality issues present themselves in the next three days the remainder of the fry will be transferred, I don't anticipate any. I need the space because I have plenty of females holding eggs right now.

I know that Blues are not known to be the easiest of the Oreochromis species (I have no experience with others), but I honestly can't imagine them being any easier. I have a modest total poundage of +/-75 pounds around the farm right now. I had 25 pounds delivered in the spring, though he gave me 32 pounds. By best calculations I have tripled my weight in three months. Most were 4 inch fish, and the bulk were stocked in my 1/4 acre pond. The average fish we are catching now out of the pond by rod and reel are now 8- 10 inches long. Males being on the larger end, and females on the smaller.These fish are going into a 700 gallon clean out tank, and are slowly being consumed by my family. As temps start to cool, we will seine the pond, and retrieve as many as possible before winter kill.
In grow out tanks I have false bottoms made of 1/2 inch hardware cloth to prevent egg gathering by the females, which really helps in reducing the male/ female size differential. Though males till grow larger.
Oh, a little tidbit of info in case any of you guys stock tilapia in ponds, and want to catch them by angling. Stubby Steves pellet lures! http://www.stubbysteve.com/ These little pellets mimic fish pellets, and work great for catching any feed conditioned fish. They were highly recommended to me, and I bought a few. They work great. Tilapia are not much for the fight the first 10 seconds is impressive, then they just roll over and drag in.

08-28-2010, 04:57 PM
I went ahead and relocated the rest of the fry. Not even close on total number. What I thought was half was less than one third. We had by our best hand count. Actually counting them as we pulled them from the net, not just estimating, 925 fry. The average weight was taken by a single net scoop, and getting 30 fish, and weighing, and dividing. Slightly less than what I would have guessed, but they averaged slightly over one gram per fish. I would have guessed more by looking at them. But I am certain the two inch fish are catching my eye more than the one inch fish. I will continue to update, as I plan to weigh every week to adjust my feed ration.

08-28-2010, 05:53 PM
how much water capacity in the green house. sounds like you are going to have a full house.

08-28-2010, 07:25 PM
Roughly 1800 gallons give or take. So yeah, if allowed to grow out to harvest size, I have a full house. But my target market are people much like ourselves. An extension agent is coming to visit Monday morning to discuss a workshop for teachers that I am speaking at. These teachers are building systems , and need to stock them. That is where I hope to come in. As a small producer, I would rather not try to compete with the big guys for food fish production, I want to cater to backyard producers, and learning institutions. The big guys don't want to sell 50 fish to a local teacher. And of course I want to supply my own table. Thanks for replying.

08-28-2010, 10:02 PM
Great posts ..... glad you're eating the product, as well as getting others interested in the Aquaculture/Aquaponics. Keep up the good work!

08-29-2010, 03:36 AM
Hi Brier, Interesting post.... :)
I'm glad to hear, that it's not just my fry/fingerlings, that grow at a noticable differant rate... :o

08-29-2010, 07:01 AM
No, it is normal in all the species I've kept. This isn't just tilapia, but many fish, snails and crayfish as well.

08-29-2010, 07:31 AM
Thanks guys! I agree with badflash here. I have seen this in every species that I have successfully bred. You may think you are the odd man out when you visit a hatchery, and see all the tanks of nearly identical sized fish, but a lot of time has been put into sorting these fish. In fact I am certain that If I were real production oriented, I would take the time to sort them so that each size class could be fed for optimal growth. There are many reasons for the size differential, but I think that the primary difference is aggression. I notice that many fish rise to the top and come half out of the water at feeding time, and others mill around below taking the crumbs that drop through. As soon as the feed at the top is eaten the more aggressive fish drop down, and start eating the crumbs as well. These are typically your larger fish. Though not always.

08-29-2010, 09:37 AM
I agree that agression plays a role, but there is a natural reason. Nature usually has an ace in the hole. The little guys can hide better and eat smaller food. If some upset comes along or a new predator shows up, the little guys may survive where the larger ones get wiped out.

08-29-2010, 03:47 PM
That is a good point badflash. I believe many fish species have populations where there are large individuals, and then a sub population of adult "dwarf" fish. Brook sticklebacks, and arctic char come to mind.

08-29-2010, 06:43 PM
Shrimp and snail species do this as well.

Big Al
08-30-2010, 07:01 AM
hi brier, good luck with your extension agents visit this week my agents up here in northeastern ohio are very intrested as well there coming in mid september for a visit. have you meant with anyone from southcenter yet. there a bunch of great people and very knowlegable. ive dealt with them often. best of luck Big Al

08-30-2010, 05:05 PM
Al, the lady that came today was Lindsey Mandau. She is out of the Reynoldsburg, Ohio facility. I have been in contact with Laura Tiu from south center. They are both a wealth of information, and very positive about small scale systems. My visit went great. Lindsey was impressed with my set up. She said they see it all, from well thought out systems to scrapyard systems. I enjoyed the visit, and it looks like I will be speaking at the workshop September 28th. I am looking forward to it, though I am a bit nervous. I am not well polished when it comes to public speaking. I will do fine, I am sure. Shoot me a PM sometime, we should chat. I would like to know more about your setup, and what other Buckeyes are doing. I certainly hope your visit goes well also.

Big Al
08-31-2010, 04:54 AM
hi brier, you are right it is nice to have both lindsey and laura in our state to help us. ive meant them and spoke with them both also. congrats on you speaking engagement. Big Al

08-31-2010, 07:01 PM
Thanks Al. I am very impressed with your set up! Forgive me for not searching enough, but what species of fish are you keeping? And how big are your fish tanks? What are your market plans? Thanks, Matt

08-31-2010, 08:58 PM
You will be great just have a couple beers and imagine your talking to your pigs ,kinda what a room full of people sound like anyway :lol: :lol:
We also have chatted enough to know you won't be at a loss for words .
Have A Kind Day

Big Al
09-01-2010, 04:59 AM
Hi Matt, I'm raising yellow perch my tanks right now are 2 275 gallon ibc's on the first system and the same on the second one also. thanks Big Al

09-11-2010, 10:34 PM
Where can I buy blue tilapia? I'm looking into starting a small aquaponics system in my basement.

09-12-2010, 06:34 AM
The author of this thread is in your neck of the woods. Give him a PM.

09-14-2010, 07:38 PM
Thanks Badflash.

09-25-2010, 07:49 PM
Just to add, as badflash mentioned, I really have plenty of blues, so if any are interested in trying some out, give me a holler.

I have not yet re-weighed any from this batch, but most are now a solid 3 inches with a percentage nearly 4. We have almost doubled our size in what? a month? Pretty amazing fish. I look forward to working with some other tilapia species as well once I get my greenhouse heating system dialed in. I might add some catfish fingerlings soon, just in case my heating set up is inadequate, at least some fish will survive, and the plants wont starve. I will post some pictures of the whole set up once it is worthy.