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Separating the males and females?
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Author:  Aquamon [ Apr 8th, '10, 01:22 ]
Post subject:  Separating the males and females?
Tilapia breed like crazy in the right conditions. I was thinking I would just leave them together and if I end up with a ton of babies then so be it. However in a recent discussion I was enlightened to the fact that the females will stop eating, there fore stop growing, when they have eggs or fry in their mouths. So, if I place something like an egg crate across the bottom that would not allow them to pickup the eggs would that keep them from having this issue or am I way off?

The other solution would be to keep them separated. If that were the case I would have my fingerlings tank and two grow out tanks. When I stocked the grow out tanks I would have to identify their sex as a fingerling then place them in the appropriate tank. Is sexing at a 2" length an easy thing to do? I'm not really asking how, but if it's possible.
Author:  TCLynx [ Apr 8th, '10, 01:43 ]
Post subject:  Re: Separating the males and females?
2" might still be a bit small for sexing tilapia though they probably could start breeding somewhere around the 3-4" mark so your window of opportunity is limited. Manually checking gender is tricky and definitely prone to error, especially when some fish are slower to develop than others making it even harder to tell.

You might be better off having a cage bottom or a cage in the tank that way they can't pick the eggs back up.

Then again, I'm not bothering with tilapia anymore myself as it was too hard for me to keep my central Florida system warm enough over winter. (granted my greenhouse was only single ply greenhouse film but I did have over 1200 gallons of water and 1400 gallons of gravel and the block wall of my garage as thermal mass and venting the dryer into it and doing laundry on cold nights.) Even with solar heating during the day, it was not enough to keep tilapia alive here with our kinda hard winter. To keep Blue tilapia alive up there, you are gonna need some major heating. I like catfish so they are our main fish now. If you can't keep the water over 70 F year round, you might think of blue gill if you don't like catfish. Tilapia won't be growing when the water is below 70 F, they might survive down to 55 F but they are not growing. Blue gill might take two years to grow out but in my experience, if your water is below 70 F for 6 months of the year, the tilapia are a slow grow out too. Now if you are starting with 3-4" tilapia fingerlings and they are all male, you might grow them out to table size with 6 months of 80+ F water but with mixed gender and cooler water, the grow out will probably be two years so you might as well use blue gill which will survive cold as long as they are not babies when it happens.

That is just my 2 cents though. If you got free heat for the greenhouse then tilapia might be a fine choice.
Author:  kellenw [ Apr 14th, '10, 02:51 ]
Post subject:  Re: Separating the males and females?
TC - I think you were probably using some pretty lousy tilapia in your system. I regularly growout 1 pound plus tilapia in 6 months time. If pushed, I can get bluegill to harvest size in about 10 months and yellow perch take about 12 months.

Aquamon - A mesh floor or growing in cages works wonders to prevent spawning. The females will still grow at a slightly slower rate than the males, but they won't be too far behind. Personally, I like the cage method, because you can grow crays, clams, prawn or a different kind of fish outside of the cages. It also makes for quick and easy grading of fish into size classes, and in turn, extremely fast harvesting. Using a series of cages, you'll be able to harvest fish on a regular basis without disturbing the others in the tank who aren't yet ready.
Author:  TCLynx [ Apr 14th, '10, 03:54 ]
Post subject:  Re: Separating the males and females?
Well I was growing Blue Tilapia which are the ones allowed here in Florida. I agree it is possible to grow out from an advanced fingerling to edible size in 6 months of hot weather and high quality food provided there is no breeding going on. I have also found that getting fish up to 2 lb or higher takes too long and trying to keep my water warm enough to keep tilapia alive (let alone growing) over winter is too costly for my taste.

I've grown catfish out to eating size in 6 months of not hot weather before and we like the catfish better and they are easier to clean so it is kinda a no brainer here, we are gonna stick with catfish.
Author:  kellenw [ Apr 14th, '10, 05:56 ]
Post subject:  Re: Separating the males and females?
TC - The thing about blue tilapia is that while they can sometimes tolerate a few degrees cooler water temps (depending on the actual line of blue tilapia... some don't), they grow slower than most nile strains. If a person has a 6 month growing window and treats tilapia like an annual "crop", the nile will far outperform the blue in terms of growth rates and feed conversion rates. We, along with several other area growers, are successfully growing nile tilapia out in 6 months time in Kansas and Missouri. I know of no one in my immediate area currently using blues. A lot of the blue tilapia stock available is from unmanaged pond populations, mainly from Florida. They are far from an ideal fish for high density growing methods such as aquaponics or aquaculture. Any positive influence on growth characteristics imparted by selective breeding and sound genetic management by growers/breeders are most likely lost through the generations of inbred pond progeny. I know of only one person in the US who is managing a really high quality of blues. Granted, you are stuck with blues in your situation, but I wonder if you would have developed a completely different opinion of tilapia had you had access to better stock. Catfish are a good fish to use though, and if you like the taste I see no reason to feel compelled to switch. Not to my liking taste wise, but fast growers, and I love to fish for them out at my pond. If I lived in Florida and tilapia was out of the question, I would probably opt for coppernose bluegill over catfish considering their excellent growth rates compared to their northern/standard bluegill counterparts.
Author:  BatonRouge Bill [ Apr 14th, '10, 06:16 ]
Post subject:  Re: Separating the males and females?
kellenw wrote:
TC - The thing about blue tilapia is that while they can sometimes tolerate a few degrees cooler water temps (depending on the actual line of blue tilapia... some don't), they grow slower than most nile strains. If a person has a 6 month growing window and treats tilapia like an annual "crop", the nile will far outperform the blue in terms of growth rates .... but I wonder if you would have developed a completely different opinion of tilapia had you had access to better stock. .

Kellenw do you have any photos of your facility/place and of your Adult fish... I went thru all the crap to get a permit here as all tilapia are treated the same...Can you post photo's and personal stats to convence a sceptic like myself??? And what strains perform the best? I like the toughness of survivability in poor water conditions they have but the ones I have also did not show any super growth rates. I think they are blue's also.
Author:  kellenw [ Apr 15th, '10, 14:22 ]
Post subject:  Re: Separating the males and females?
Bill - I don't really have any photos to speak of, but we will be taking some soon for the updated website we are working on. I'll be sure to share those with the forum when we take them. We're also constructing a new, much larger hatchery facility this Summer, so I'm planning on documenting the whole process in a thread here as time permits. We're extremely excited for the expanded production capacity we will have as we are struggling to keep up with demand between our retail sales and contracted production demands.

From our own growout efforts, we consistently produce 1 pound plus tilapia in 6 months with our White Brook strain of Niles. Some tip the scales at up to 1.5 pounds in this time frame. It is entirely possible to do this assuming you start with quality tilapia stock, have sound water quality management, employ effective filtration, stock the fish at appropriate densities for your system's capabilities and use high quality feed. Some people are misled by a few, let's just say "less than honest" small time tilapia suppliers, into thinking tilapia are "magical" fish, capable of growing to amazing sizes in terrible water and using low quality (cheap) food, and that simply isn't the case, so I can understand a lot of people's frustrations when their results fall far short of their expectations. It's not hard to get fast growth with quality stock, but don't expect "magic" to happen either. :) Our fish strain is a very fast grower, but there are many others grown around the world that are equally as fast or even slightly faster growers too. However, very few are available in the US, and virtually none are available in quantities less than about 5,000 fish that I know of, and certainly not available in any form but hormonally sex-reversed all male stock here (in part to protect the hatcheries' valuable investment in stock from competition). For instance, the Chitralada strain of Niles is documented to grow up to 1.6 pounds in 6 months. The "GIFT" strain of Niles (developed by the International Center for Living Aquatic Resources Management) is documented to grow up to 1.7 pounds in 6 months. The Nam Sai Nile strain is documented to reach up to 1.76 pounds in 6 months. The "Big Nin" Nile strain is reported to attain 1.5 pounds in just 5 months.

The problem in the US is that most of the stock that can be obtained by small scale growers is extremely low quality.
Author:  Yaacov Levi [ Jun 18th, '10, 08:20 ]
Post subject:  Re: Separating the males and females?
I mentioned this before in other threads but you can buy improved growth strains ofn Tilapia from Israel , Kibbutz Sde Eliyahu, they ship all over the world, and have a red strain that rivals any strain anywhere.

I am getting some fingerlings from them this year, their Colorado Whites and their O.aureus for growth and production trials.

google Sde Elihau.org

It will come up.
Author:  DéjàVoodoo [ Jun 18th, '10, 08:33 ]
Post subject:  Re: Separating the males and females?
Yaacov Levi wrote:
google Sde Elihau.org

It will come up.



It will???? I got a few hits but nothing that looked like it was related to fish???? I wont click any links I think could be harmful.
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