Aquaponics Digest - Sat 01/31/98
Message 1: Re: Tilapia sexing and breeding
from Gordon Watkins
Message 2: Re: Life's small pleasures
from Gordon Watkins
Message 3: Palm fronds
from S & S Aqua Farm
Message 4: (no subject)
from minam
Message 5: Re: Life's small pleasures
from GCR
Message 6: Sexing and Breeding Tilapia
from "Geoffrey Stone"
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Subject: Re: Tilapia sexing and breeding
From: Gordon Watkins
Date: Sat, 31 Jan 1998 10:32:15 -0600
Pete,
I'm also struggling with tilapia breeding and have had mixed success,
but I've been asking around and will share some of the suggestions I've
recieved.
I purchased sexed broodstock and I'm producing all-male fry, so I've
not had the need to sex the fish and can't help you there.
I have a male T. hornorum and five each of female mossambicas and
niloticas. The mossambicas have been much easier to breed and over the
last 9 months I've raised about 500 fry. The niloticas are slower to
mature sexually and mine are just now showing some interest. They're
about 7" long. I have all in a 70 gal aquarium with a bare bottom, large
sponge filters, and a powerhead for aeration and water movement.A larger
tank would probably be better, but it's what I've got to work with. I do
50% weekly water changes. I placed a 10" diameter pottery crock on its
side on the bottom as a territorial target for the male, which helps
somewhat to reduce aggression. It also helps when transferring an
egg-carrying female. I just herd her into the crock, place a net across
the mouth, and gently lift the crock out of the water and place it in a
15 gal. maternity tank where the female is released. I've found she's
much less likely to spit eggs this way, compared to netting. Once the
fry are free-swimming, I transfer the female to a conditioning tank
where I feed her well for a week or so before moving her back with the
harem.
On the recommendation of a fisheries extension agent who managed a
tilapia hatchery, I feed the breeders 32% catfish pellets with added
soybean oil, which is reported to increase the egg count. My fish are
too small to produce many eggs yet so I can't confirm this practice, but
the fish eat it eagerly. It's been recommended that I feed live or
high-quality frozen food and I plan to begin feeding earthworms and
frozen brine shrimp. I feed the fry a 42% crumble which I crush with a
mortar and pestle until the fish are large enough to take full crumbles.
I have a flourescent light on a timer (15 hrs/day) over the breeding
tank and keep the temp at 85+. It's been recommended to raise it to 92.
My male had been less than enthusiastic most of the fall and I suspected
that perhaps he had become sterile, but after adding the lights and
raising the temp from 80 to 85 he became much more active and the
mossambicas began breeding again. There seemed to be a strong
corellation between day-length and breeding activity. I'm still waiting
on the niloticas.
I have 6 large (1 lb+) Rocky Mtn Whites which I got from the Speraneos
last spring and I have never seen any breeding behavior from them. I've
not tried to sex them, but the odds are that there would be at least one
male or female unless they're a predominantly male cross. Does anyone
know anything about the heritage of this strain?
I hope this helps. I would also like to hear from others who are having
more success breeding tilapia.
Regards,
Gordon
PeterJTheisen@eaton.com wrote:
>
> I am going to ask some very basic questions, but I could use some help. I
> have been only marginally successful at breeding tilapia. I am not after
> producing thousands of fry, I just want to do a better job and know what I
> am doing.
> Questions:
> Is there an easy way to tell males from females? I have been told that the
> only way is based on the shape to the opening on the belly of the fish and
> that to be accurate it requires the use of a dye of some kind. When I just
> look at my fish in their private areas they all look alike. And no, I at
> present do not have all male fish. I primarily have Rocky Mountain whites
> I obtained from the Speraneos.
> Are there optimum conditions that encourage the tilapia to breed. I have
> set up a 50 gal tank with a 3 inch pea gravel bottom I heat it to 78 to 80
> deg F., provide good filtration and oxgenization and feed them what they
> eat in 5 min. three times a day. I have added no light, the tank is lit by
> the other light around the room. Is there anything I should/could do to
> improve breeding conditions?
> Do Fry and Fingerlings benefit from special foods, Such as high protein
> crumbles and ??? Will broken up normal catfish or trout chow do just fine?
>
> Pete T.
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Subject: Re: Life's small pleasures
From: Gordon Watkins
Date: Sat, 31 Jan 1998 10:49:41 -0600
Hi Paula,
I don't think you're being off-topic at all. Anecdotal experiences can
be as useful as controlled research, particularly when most of the work
is being done by growers like yourself who have limited time and
resources to devote to replicated experiments. Keep it up!
I've been toying with the idea of growing strawberries in vertical
towers to get them up off the damp gravel and improve air circulation.
We grew strawberries commercially for 10 years and our biggest
challenge, besides weeds, was botrytis, or grey mold. A rainy spring
could be devastating since we didn't use fungicides, so the damp
conditions and high humidity of a greenhouse are particularly
threatening. I've thought about stacking tapered pots filled with media
with plants set around the edges of each pot, or using lengths of 6" or
8" pvc pipe with holes cut in the sides and filled with media. Towers
would also make good use of floor space. Water could be pumped to the
top and would perc through. I'm encouraged that you found adequate
nutrients to produce a crop.
I've also considered using the day-neutral varieties, which should
produce more dependably during the winter.
Thanks for the tidbits and don't be shy about offering more.
Regards,
Gordon
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Subject: Palm fronds
From: S & S Aqua Farm
Date: Sat, 31 Jan 1998 12:14:30 -0600
Can anyone give me any information on the uses for palm fronds or a web site
recommendation.
I've made cuttings from a palm and have many 3' long, 2-1/2" at the widest
section, pointed (with razor sharp edges) fronds that I feel I should find a
use for. Any ideas?
Paula
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
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Subject: Re: Life's small pleasures
From: GCR
Date: Sat, 31 Jan 1998 14:16:34 +0000
Don't apologize. It is this kind of off-the-wall investigation that lead
to real discoveries. Let the big boys laugh.
My first patent for rhea and ostrich patent as an injectable therapeutic
and anti-inflammatory agent was just approved based on research done in my
barn. One of the deciding factors was that was using a new technique,
similar to blood transfusion, by replacing the depleted body fat in the
wasting syndrome in rhea chicks. It started just like this.
I think this is very on-topic. Thank you.
Donna
At 07:11 PM 1/30/98 -0600, S & S Aqua Farm wrote:
>Sorry if this is off-topic - We've just "harvested" our first strawberry
>from the growing beds. Another one of those "silly experiments" that we
>can't seem to resist. I took, last July, several thinnings from my
>brother-in-laws "June-bearing" strawberry plants from his garden. After
>several weeks, I managed to get the plants into the growing beds (they had
>been kept in pots with their roots barely covered in soil outside after an
>8-hour trip from his place).
>
>Sorry to take list space for this, but it's one of those things that simply
>must be shared. I apologize to our researchers and those who must read this
>as part of their business.
>
>Paula Speraneo
>S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
>Web page http://www.townsqr.com/snsaqua/
>
>
Donna Fezler@rhealiving.com
GCR
1620 Baldwin Road
Jacksonville, IL 62650
USA
(217) 243-7683, fax 245-2919
*Leading the world in Rhea Research and Product Innovation
*Inventor of the dietary supplement Rhea Extract
*Pioneering research on the role of environmental toxins in autoimmune
disorders
(web page temporarily offline while we change servers)
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Subject: Sexing and Breeding Tilapia
From: "Geoffrey Stone"
Date: Sat, 31 Jan 1998 21:47:47 -0600
The following is from a draft of a book Mike Sipe made available through =
an on-line school he conducted through America On Line a year ago or so. =
I followed his recommendations and set up a 50 gallon aquarium and got =
them to reproduce. I had problems as I have a "green" system...that is =
I have my tanks in the sun of my greenhouse which results in algae =
growth...a source of food for the fish. This made observation of the =
fish in the breeder tank difficult. At the suggestion of Dr. Nathan =
Stone of the UAPB I covered this tank to discourage aglae growth and =
provided artificial light. After awhile I observed a fish with a =
"double chin" which, when I attempted to catch her, spewed out her eggs. =
This possibility was discussed by Mike Sipe so I was prepared. I =
cought her and put her in a nursery tank and siphoned up the eggs into =
the same tank. I had my first fry in a few days.
Since then I have observed schools of fry in my larger (400 gallon) tank =
swimming near the surface which I scoop up and put in floating nets. =
These I surrounded by a 1/2 by 1/2 wire cage to keep the larger fish =
from the nylon net containing the fry. As my system is a "green" one =
there is plenty of algae for the fry to feed on until they can eat =
crushed up "Trout Chow".
We visited the UAPB Aqua Research station where we were shown their =
method of sexing the fish. The professor used a piece of straw (which =
he obtained from a nearby broom) and dragged it across the sex organs of =
several fish, It "caught" on the slit of the female fish as compared to =
it smoothly sliding across the cone opening of the male fish. He =
admitted that this technique is not always successful however.
By no means do I claim to be an expert, but I have had enough success =
for my purposes. =20
Geoffrey Stone
FISH SEXING AND BREEDER SET UP (by Mike Sipe)
The next job is to determine which fish are male and which fish are =
female. This is done by checking the reproductive organs on the =
underside of the fish. The fish has two to three exit areas depending on =
whether it is a male or a female. The first hole is the anus through =
which waste material produced in the digestive system is voided. This is =
located just to the rear of the belly on the bottom of the fish and is =
called the anus. The second organ just to the rear of that is called an =
anal papilla and is shaped like a small cone. This organ serves as both =
the urinary opening and as the channel for sperm to be ejected prior to =
fertilization.
The male only has the cone shaped papilla, where the female has an =
additional opening near the middle of the papilla to allow eggs to be =
ejected during mating. The tilapia are able to breed as young as 60 days =
after hatching from eggs themselves and as small as 2 or 3 inches in =
length and one ounce in weight.
The problem is though, at that size it is still difficult to see the =
difference between the sexes even with magnification. The size I =
recommend though is large enough for the difference to be easier to see. =
If we still have a problem then it is possible to make the ovarian =
opening more visible with a dye such as gentian violet. A cue tip is =
dipped in the violet colored liquid and drawn quickly and lightly over =
the papilla from front to back. The dye tends to concentrate in any =
crevices or openings thus outlining them for better visibility.
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
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