Aquaponics Digest - Thu 03/19/98
Message 1: [Fwd: Talapia and salt...]
from S & S Aqua Farm
Message 2: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
from John Shannonhouse
Message 3: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
from crystal
Message 4: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
from Linda Wymore
Message 5: economics
from james.rakocy@uvi.edu (James Rakocy, Ph.D.)
Message 6: Re: economics
from "H.Doelle"
Message 7: Re: Seaweed Extract addition for aquaponics systems
from S & S Aqua Farm
Message 8: Aquarium Plants, was Re: Partial Water Changes
from S & S Aqua Farm
Message 9: Water hardness/fish tolerance, was Re: Partial Water Changes
from S & S Aqua Farm
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Subject: [Fwd: Talapia and salt...]
From: S & S Aqua Farm
Date: Thu, 19 Mar 1998 07:15:12 -0600
>Date: Wed, 18 Mar 1998 22:11:06 -0500
>From: Jan Kirchner
>Date: Wed, 18 Mar 1998 16:06:44 -0400 (AST)
>To: Jan Kirchner
>From: james.rakocy@uvi.edu (James Rakocy, Ph.D.)
>Subject: Re: Talapia and salt...
>
>Dear Jan, I almost lost you. If I don't respond immediately and your
>messages gets pushed back on the list of incoming mail, it's gone, straight
>out of my mind, but I kept thinking there was something about Anguilla. I
>think wells would be too salty, too much sodium chloride, but you might add
>reverse osmosis to get purer water. Also after pumping heavily, you might
>get saltwater intrusion. In aquaponics nutrient salts generally build up,
>especially in the type of closed system that you would have to use in
>Anguilla. In drip systems on land you can get away with somewhat higher salt
>levels by using water to wash out the salt that accumulates. You therefore
>stay at ambient levels. Hopefully the plants can tolerate this. There is a
>hydroponics operation on Anguilla and they used to use reverse osmosis on
>saltwater for their supply, but they did have problems with high boron
>levels. There's no problem with salt and tilapia. We've raised red tilapia
>in ocean cages. It takes 5 days to acclimate from freshwater to saltwater.
>Some species such as Mossambica tilapia tolerate twice the strength of
>saltwater. This species is in most of the salt ponds on Caribbean. It was
>brought to the West Indies in the late 40s and early 50s. Nile tilapia are
>less tolerant of salt but still do well at half strength seawater. Jim R.
>
>>Dear James -- I read with interest your post about rainwater catchment
>>and use for your hydroponic systems. I am investigating the "aquaponic"
>>design application on Anguilla in the northern reaches of the Caribbean.
>>
>>As I'm sure you know, rainfall there is minimal at about 27" per year I
>>believe. Catchment and cisterns are a great aid and a must, but how
>>about the well water? The Canadians have drilled various wells on
>>Anguilla as a secondary water supply and I am aware that growers can use
>>higher salinity water if the water keeps dripping or moving.
>>
>>Do you have any experience/advice on the effect of such water on Talapia
>>fish?
>>
>>In advance, thanks for reading and I look forward to your reply, which I
>>will share in the aquaponics group.
>>
>>Sincerely, Jan Kirchner
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Subject: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
From: John Shannonhouse
Date: Thu, 19 Mar 1998 10:19:22 -0600
<>
Cultivation of transgenic lines of plants should use the same
techniques as for nontransgenic lines. The only considerations are that
(1) you need to be able to follow your "marker" (a gene put into the plant
when it was transformed so the transgene of interest or, in cases like the
Flavr Savr, the gene that was knocked out, can be monitored) and (2) you
need to take measures to insure that the transgenic line does not get out
into the wild. Often people assume that #1 is easy and #2 is difficult,
but that is not usually the case. Transgenic lines that are put out in the
field are often made so that they are sterile. Transgenic lines usually
either grow slower, are less fertile or otherwise have problems so that
they can't compete with wild strains anyway. When I was working on a
project that involved engineering mercury resistance into plants, our lab
was pleasantly surprised to learn that the plants did not grow well unless
there were at least mildly toxic levels of mercury in the growth media!
Monitoring the marker can be a real pain. Often transgenes (including
markers, usually kanamycin resistence) are "silenced" in plants with
passing generations. This means that the marker must be followed by
looking at the DNA directly rather than by following some easilyu assayed
phenotype. The method of choice today is PCR, which I find to be very easy
and cheap (though many people disagree with me).
BTW, if any of you ever grow transgenic lines of plants because
they express a transgene (as opposed to a line that has a gene "knocked
out"), be sure to ask your suppliers if this line has been through enough
generations that they can be sure that gene silencing won't be a problem.
<>
That depends on how you want to do your engineering and on what
species of plant. I can give you the email addresses of a number of plant
geneticists if would like.
John Shannonhouse
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Subject: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
From: crystal
Date: Fri, 20 Mar 1998 01:20:32 -0800
Hi, John.
Are you an Israeli? ;)
Transgenic lines? Sounds like a secret high-tech research facility.
Well, what ever trans-knowledge you have you can pass it on to me. Yes,
the email address would be nice.
Best Regards,
Crystal.
(Excuse the joke. I know many Israeli researchers are on agricultural
lists everywhere. Seems they are even on aerospace topics, nowadays. Are
you guys planning to form a space colony by yourselves - like NASA? ;) )
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Subject: Re: RAFI News: Terminator Technology to Hurt Farmers (fwd)
From: Linda Wymore
Date: Thu, 19 Mar 1998 09:45:56 -0800
crystal wrote:
>
> Hi, John.
> Transgenic lines? Sounds like a secret high-tech research facility.
> Well, what ever trans-knowledge you have you can pass it on to me. Yes,
> the email address would be nice.
>
> Best Regards,
> Crystal.
Hi Crystal. Excuse my responding to your post to John, but I
sent Jim S some info - some links - and on the chance that you
(or someone else on the list) might find in the links the info you are
seeking.. here's the post I sent to Jim. Linda
---------------------
Jim S wrote
>
> Thanks for posting this info Linda.
> I'd been led by my seed suppliers to believe that it would only affect
> beneficial changes, but your post has caused me to look deeper. Potential
> damage to existing varieties is too high a price to pay, ...
You're welcome Jim. In response to Donald's posting of the
original article I found more info on this site. Here's the
link.. and a few more, if you want to look deeper.
http://www.rafi.ca/
Rural Advancement Foundation International
RAFI is dedicated to the conservation and sustainable
improvement of agricultural biodiversity, and to the
socially responsible development of technologies useful to
rural societies. RAFI is concerned about the loss of genetic
diversity - especially in agriculture - and about the impact
of intellectual property rights on agriculture and world food
security.
http://www.monitor.net/rachel/r549.html
Here's the article about the genetic engineering error that
I mentioned in my post. Interestingly, the company is Monsanto
which is poised to buy out the Co. that developed the Terminator
seed. The article is from Rachel's Environment and Health Weekly,
which has a number of other interesting articles on their website:
http://www.monitor.net/rachel/rehw-index.html
http://www.sage-intl.org/refer.html
A reference list of articles on the risks of genetically
engineered crops
http://ecoweb.dk/ifoam/gmo/petit1.htm
Here's some info about B.t. engineered crops
http://www.inhs.uiuc.edu/cee/wwwtest/movement/research.html
More about B.t. transgenic corn
Well, that's a start. There's ton's more info on the web, just
do a search for some of the key words - biodiversity, "transgene
crop spread", "genetically engineered", etc. Good luck.
Linda
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Subject: economics
From: james.rakocy@uvi.edu (James Rakocy, Ph.D.)
Date: Thu, 19 Mar 1998 15:11:46 -0400 (AST)
>I'd be really interested in finding out more about the economics of
>aquaponics and aquaculture... As someone with really no experience in
>farming fish and/or hydroponics this is all, for right now, just food for
>thought... How would the economics of aquaponics make it an
>economically viable food source for developed/developing countries- I'd
>love to hear about any research done on this and any comments from
>the list
>
>Hank Morton
Hello Hank, We have written a paper on the economics of an aquaponics system
(tilaia and lettuce) in the U.S. Virgin Islands. It appears to be
profitable. Profits increase with economy of scale. We also have a nich
market with high tilapia and lettuce prices. My feeling is that commercial
aquaponics will always have to have a niche market (upscale restaurants,
etc.) to make money (a good reason for locating them close to large urban
markets). Another possible alternative would be to locate systems in low
wage areas (developing countries like most companies do these days) and
export product to large high priced markets. I don't think aquaponics will
ever compete successfully in commodity markets, although I would like to be
proven wrong here. How are the commercial operations doing? Paula, care to
reveal your books? Jim R.
P.S. Here are some additional comments from Don Bailey, a colleague and
lurker. "Most of the revenues come from lettuce sales and most of the
capital costs go to fish production. It is better to consider the
hydroponic area as a revenue generating filter for tilapia production than
the tilapia as a nutrient generating component for vegetabel production. I
think that you have to be a fish farmer first, looking for filter options to
get involved in hydroponics. A hydroponic farmer would not go to the
expense and technology needed to add fish to his system when inorganic
nutrients are
inexpensive.
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Subject: Re: economics
From: "H.Doelle"
Date: Fri, 20 Mar 1998 07:29:04 +1000
Hank,
It is my opinion that the economics can be improved significantly through
integrated systems. You may specialise on fish breeding and production, but
if you produce energy from waste and algae for feed, you may be more economic.
I think the future lies in multi-product systems and make the most out of
the carbon and nitrogen available.
In Asia and Pacific we are teaching and establishing these integrated
systems, using animal/human waste, producing energy [biogas] through
anaerobic digestion and using the effluent for algae, duckweed and other
fish products. This you can observe in China, now also in Fiji and soon, I
hope, in the Pacific.
Horst
At 03:11 PM 19/03/98 -0400, you wrote:
>>I'd be really interested in finding out more about the economics of
>>aquaponics and aquaculture... As someone with really no experience in
>>farming fish and/or hydroponics this is all, for right now, just food for
>>thought... How would the economics of aquaponics make it an
>>economically viable food source for developed/developing countries- I'd
>>love to hear about any research done on this and any comments from
>>the list
>>
>>Hank Morton
>
>
>Hello Hank, We have written a paper on the economics of an aquaponics system
>(tilaia and lettuce) in the U.S. Virgin Islands. It appears to be
>profitable. Profits increase with economy of scale. We also have a nich
>market with high tilapia and lettuce prices. My feeling is that commercial
>aquaponics will always have to have a niche market (upscale restaurants,
>etc.) to make money (a good reason for locating them close to large urban
>markets). Another possible alternative would be to locate systems in low
>wage areas (developing countries like most companies do these days) and
>export product to large high priced markets. I don't think aquaponics will
>ever compete successfully in commodity markets, although I would like to be
>proven wrong here. How are the commercial operations doing? Paula, care to
>reveal your books? Jim R.
>
>
>P.S. Here are some additional comments from Don Bailey, a colleague and
>lurker. "Most of the revenues come from lettuce sales and most of the
>capital costs go to fish production. It is better to consider the
>hydroponic area as a revenue generating filter for tilapia production than
>the tilapia as a nutrient generating component for vegetabel production. I
>think that you have to be a fish farmer first, looking for filter options to
>get involved in hydroponics. A hydroponic farmer would not go to the
>expense and technology needed to add fish to his system when inorganic
>nutrients are
>inexpensive.
>
>
>
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Subject: Re: Seaweed Extract addition for aquaponics systems
From: S & S Aqua Farm
Date: Thu, 19 Mar 1998 21:44:48 -0600
At 08:38 PM 3/18/98 -0600, you wrote:
>Paula, What rate did you use for adding Maxicrop to your tanks?
> Gordon
Gordon - using the granulated formula diluted to concentrate (the
concentrate formula, I believe, calls for 2 Tbl per gallon of water for
foliar spray), we add approximately 1 cup into our 800 gallon tanks. I
don't "know" that you can "overdose" the system with too much, as primarily
what it provides is the enzyme for the plants to uptake available nutrients,
but suppose it is possible.
The outside organic growers who first introduced us to Maxicrop (Tom and
Angel Kruzen - I think you know them) said they saw visible differences in
yield and general health of their plants. Knowing their operation, I would
say that the plants had proper nutrients for good growth, but the Maxicrop
resulted in a substantial boost in the plant's ability to use them.
All of this is anectodal, I know. I do know that we've seen no significant
negative affects in the fish (haven't evaluated for increased growth,
health, etc.), and generally better overall health and production from the
plant side.
Hope this info is of some use.
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: Aquarium Plants, was Re: Partial Water Changes
From: S & S Aqua Farm
Date: Thu, 19 Mar 1998 21:44:50 -0600
At 05:01 PM 3/9/98 -0500, Wendy wrote:
>Thanks for answering my questions. I have more.
>Paula wrote:
>> Not having raised aquatic plants, we don't have the necessary experience
>to
>> compare their filtering capabilities with the crops we grow. I would be
>> interested if anyone else can explain the differences, though, as we've
>> often considered growing aquatic plants for the home aquarium industry.
>>
>I'm not sure about the nutritional differences, but I certainly recommend
>raising aquatic plants for the home aquarium trade. I raised water sprite
>and several species of Hygrophila, and a friend raised Java fern. Nether
>of us ever had any problem selling our plants. Water sprite requires a
>high level of nutrients in the water or it just languishes. It a real good
>seller because it doesn't ship well so most petshops and distributors
>cannot get nice plants. It disintegrates very fast if kept out of light
>for long. Many pet shops usually don't carry it because of the condition
>it usually arrives in. So if you have a distributor near by, that you can
>deliver small quantities often you will have a good customer.
Thanks for the input on your aquarium plants - makes it sound like a great
idea to grow, then ship in water-filled containers to a local market.
Hygrophila,
>I have noticed, is a good indicator of water quality. If the ammonia or
>nitrite levels start to creep up, it begins to look sickly and put out
>small leaves, even before my fish would act bothered. Java fern is a hardy
>slow grower that is not bothered by most plant-nibbler fish. The wholesale
>prices it gets reflects its slow growth nature.
Sounds like a great indicator plant that would enable growers to "advance"
monitor water quality - especially helpful - thanks!
>
>Most plants in the hobby trade are actually bog plants and require a period
>of emersion in order to bloom and set seed.
>
>With aquatic plants, I found that if I increased the plant/fish ratio to
>the point that I was maintaining good nitrate levels, my water would become
>too oxygenated for my fish. The fish did fine in there, but if they were
>moved to a more "normal" environment, they developed "gas bubble" disease
>from the sudden drop in oxygen (the pet shops didn't like that at all
>(oops)). Of course this wouldn't be a problem with terrestrial plants
>because they are releasing oxygen into the air instead of into the water.
>But the point is that I had to keep an incredibly high ratio of plants to
>fish for the nitrate levels to stabilize, so I just went back to partial
>water changes.
>
I wonder if a good mix of submerged and terrestrial plants would relieve
this condition without affecting the fish stress on change of systems -
definitely food for thought.
Wendy - thanks for the detailed post (almost reads like a tvo post!). I'll
try to respond to your other questions ASAP.
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: Water hardness/fish tolerance, was Re: Partial Water Changes
From: S & S Aqua Farm
Date: Thu, 19 Mar 1998 21:44:54 -0600
At 05:01 PM 3/9/98 -0500, Wendy wrote:
>Thanks for answering my questions. I have more.
>
>Do the plants also absorb the calcium etc. in the water too? In areas
>which have hard water, just adding to replace what is naturally lost
>through evaporation/respiration would result in the hardness gradually
>creeping up -- sometimes to incredibly high levels. This usually wouldn't
>be noticed in existing fish, as they will become accustomed to it (until it
>got VERY hard), but it would shock any new fish that are added.
I'll have to leave the answer to this to those with more research and
analysis experience. We haven't experienced a noticeable problem when
adding new fish to the existing system, even though the majority of our fish
have traveled under stressful conditions (by air, in a bag/box combination
for a 24-48 hour period, depending on the airlines).
My opinion is that the system itself is modifying the potential calcium
buildup in the bacterial breakdown phase to somehow eliminate the problem.
Other opinions or data would be welcome here.
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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