Aquaponics Digest - Mon 03/01/99
Message 1: Re: Subduing nitrates and nitrites
from jilli and lars
Message 2: Re: Live feed
from jilli and lars
Message 3: Re: Organic Aquatic Livestock Recommendations
from "Wendy Nagurny"
Message 4: Re: Live feed
from "Sam Levy"
Message 5: Re: Garden wall, peatcrete, bentonite and thorite
from jilli and lars
Message 6: Re: Organic Aquatic Livestock Recommendations
from "Sam Levy"
Message 7: Re: Organic Aquatic Livestock Recommendations
from "Wendy Nagurny"
Message 8: Chilling tilapia at harvest
from Adriana Gutierrez
Message 9: Re: Organic Aquatic Livestock Recommendations
from Dave Miller
Message 10: Re: Organic Aquatic Livestock Recommendations
from "Wendy Nagurny"
Message 11: Re: Graywate /Wetlands/ EcoEngineering
from jilli and lars
Message 12: Re: Graywate /Wetlands/ EcoEngineering
from KLOTTTRUE
Message 13: Re: Food
from KLOTTTRUE
Message 14: Re: Chocolate Hybrid
from khale@ballistic.com
Message 15: Re: Chilling tilapia at harvest
from Peggy & Emmett
Message 16: Re: Food
from Gordon Watkins
Message 17: Re: Subduing nitrates and nitrites
from Gordon Watkins
Message 18: Re: Organic Aquatic Livestock Recommendations
from Gordon Watkins
Message 19: Re: Chilling tilapia at harvest
from Gordon Watkins
Message 20: new member--dumb question
from "mjanes"
Message 21: Re: new member--dumb question
from William Evans
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| Message 1 |
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Subject: Re: Subduing nitrates and nitrites
From: jilli and lars
Date: Sun, 28 Feb 1999 20:25:32 -0800
Hi brian -
I'm guessing that the reason they used 50 feet of tubing is to create a
large surface area for the bacteria to grow on.
Gravel (or perlite, etc.) and plant roots (especially) have an
extreeeeemly high surface area, thought it isn't quite so visually apparent nor
as easy to measure as 50 feet of tubing.
Much like the surface area of your small intestine is _vastly_
increased my those tiny, microscopic, finger-like villi and the surface area of
your lungs is increased by the alveoli, natural dendritic surfaces like plant
roots have a much higher surface area to volume ratio than just about anything
humans have figured out how to make, which means more bacteria which means more
rapid conversion.
My guess is that a _single_ plant's roots have much more surface area
than 50 feet of smooth plastic tubing.
Plus, once the bacteria convert the ammonia to nitrites to nitrates,
the plants can absorb the nitrates right then and there.
lars fields
Brian Gracia wrote:
> I have yet another question. I went on a net safari to find the ever
> elusive "information" about amonia, nitrates and nitrites. One of the
> links I came across involved using 50ft of 1/4" tubing to raise bacteria to
> change amonia to nitrates and nitrites and nitrogen gas. Has anyone done
> this for their tank systems? I know that S&S uses grow beds and this works
> for them, but I will be using troughs to grow veggies in.
>
> Brian
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| Message 2 |
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Subject: Re: Live feed
From: jilli and lars
Date: Sun, 28 Feb 1999 20:10:06 -0800
Brian Gracia wrote:
> Anyone have any info on live feed? How bout green water?
>
> I am going to be raising large mouth bass in a large tank, as well as
> trying my hand at raising Red Snapper in another tank. Both fish like live
> feed. I have plans to raise worms, meal worms, crickets and minnows. I
> thought about raising guppies, as I understand they breed rather quickly.
hi brian -
sounds like an interesting project. I'm interested in how it goes.
worms are really easy to raise off kitchen refuse, as are crickets, so
it sounds like you could have a really cheap source of good food for your fish
(and, in turn, your family). I reccommend a mulit-tiered vermicomposter, they
work very well and don't go anaerobic. Crickets won't generally breed unless
the termperature is above 80-85 F. Guppies might eat duckweed as a staple, and
growing fruitflies might be a nice supplement to their diet.
Aren't red snappers a saltwater fish? How are you going to grow those?
Where are you going to get the fry? How are you planning on keeping the water
clean as i don't believe salt water and aquaponics would mix? I wonder about
kelp....
lars fields
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| Message 3 |
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Subject: Re: Organic Aquatic Livestock Recommendations
From: "Wendy Nagurny"
Date: Mon, 1 Mar 1999 01:54:07 -0500
I have read over this "Standard" and the comments quite a few times, and I
have some problems with this. I was hoping to see some others comment on
this, but I guess I will go first.
I would like to state first that this standard does not seem to be in the
spirit of what I think consumers want from fish that is labeled "Organic".
I know that it is not what I would expect from the "Organic" label. My
comments are added at the end of each section.
>Comments are underlined in the text below.
>
>Best regards,
>
>Eric Kindberg, certified organic farmer
>
>
>NATIONAL ORGANIC STANDARDS BOARD
>
>ORGANIC AQUACULTURE STANDARDS
>
>Second draft written by Frederick Kirschenmann
>
>Date Submitted: October 20, 1998
>
>Purpose: For review and revision by the NOSB Livestock Committee and
>submission to the NOSB
>
>AUTHORIZED METHODS AND MATERIALS FOR
>THE PRODUCTION OF ORGANIC FINFISH and SHELLFISH
>
>A. GENERAL REQUIREMENTS
>I. Fish shall be reared in a habitat that meets the basic physiological
>requirements and behavioral needs of the species being grown.
>2. To avoid escapes of domestically reared fish into the wild, and wild
>fish
>entering a farm, only enclosed, self-contained, ponds and other facilities
>will be allowed. Netcages and netpens are not allowed.
>Comment:
>In pond raised organic aquaculture we feel for each fish rearing pond or
>series of rearing ponds, there should be a sediment pond or ponds of
>similar
>size that the rearing pond water flows into before the water exits to the
>environment. A similar size sediment pond where fish are not purposely
>raised
>offers a degree of protection against environmental contamination from fish
>
>wastes, and the more likelihood of preventing disease and parasite
>contamination of the fish rearing pond. Sediment ponds offer an effective
>slowing down of the entrance of unwanted fish and wild aquatic livestock
>into
>the fish rearing pond(s).
>
>
1. Fish are not like dogs or cows. If its habitat does not suit it, it
gets even by dieing. Not too many fish would be raised in an unsuitable
habitat. Therefore, habitat regulations are unnecessary.
2. I don't think the STANDARD should concern itself with excapees. This is
up to the regulation of the states. Each state already dictates how to
contain aquacultured, non-native species in a manor suited for that state.
However, I agree with the statements about requireing contained systems to
prevent wild species from entering the rearing areas. However, how that is
accomplished, should be up to the farmer. While sediment ponds are one
method to accomplish this, it may not be the only way, and should not be
included in the STANDARD as the commentor suggests.
>B. FEED
>1. Feed components must be produced in accordance with USDA
>organic standards for livestock feed.
>2. Plant-based feed sources must be from organic production.
>3. Only feeds with low fishmeal content are allowed (no more than 20%)
>
>Comments:
>We believe that 1 and 2 above unduly restricts the sources of protein for
>feeding aquatic livestock. Wild harvest aquaculture products are allowed
>for
>crop fertility on organic farms under OFPA and in the private sector
>certification standards now. The requirement we feel that offers a
>safeguard
>from possible feed contamination of wild harvested aquatic products is to
>require random sample testing from each 2000 pounds of wild aquatic feed.
>Item 4 below is in contradiction with Item 1 above. Item 1 requires all
>feed
>to be from "organically produced" sources, while item 4, below, allows non-
>
>organically produced feed.
>
>4. Fishmeal and fish oil must be sourced from waste products of processed
>wild, marine fish or from certified organic fish farms. Fishmeal and
>fishoil
>obtained from wild caught fish will not be allowed.
>
>Comment:
>The last sentence of item 4 does not seem to be logically supportable and
>places an undue burden on organic aquatic livestock producers. The
>sentence
>should be removed.
>
>5. Artificial colors, binders and synthetic astaxanthin are prohibited.
>6. Antibiotics in feed and extrudents from fishmeal are prohibited.
>7. Feed additives, with the exception of minerals, vitamins, phaffia yeast,
>
>and enzymes of natural origin, are prohibited.
>
>Comment:
>Item 7 should be rewritten to be consistent with OFPA and the National List
>
>process. Vitamins and minerals, livestock parasiticides and medicines used
>in
>organic aquatic livestock production must be petitioned, reviewed and
>included
>on the National List by specific use and application. Under OFPA "Phaffia
>yeast" and "enzymes of natural origin," unless they are "organically
>produced"
>are not allowed to be fed as feed supplements to aquatic livestock
>producing
>"organically produced" livestock products. Under OFPA, there are no
>categories for "feed supplements" or "feed additives" open for inclusion on
>
>the National List.
1. and 2. I disagree strongly with the commentor. Organic fish must be
fed organic feed. There may currently be no source for organic feed, but
there is currently little demand. If the STANDARD required organic feeds,
they would be produced.
3. I don't think the STANDARD should state what percentage of fishmeal may
be allowed in feeds. If the species requires a higher percentage for good
health and productivity, then they should be fed it. Nutritional
requirement are too species dependent to be dictated in the STANDARD.
4. This paragraph does contradict itself. The first sentence allows
products from wild caught fish to be used in feed while the second sentence
prohibits it. I agree with the second sentence. Wild caught fish whether
fresh or marine must not be used in "Organic" feeds. There are simply too
many toxins present in these sources that can be passed on in the fish.
Fish oil and meal must be from certified organic sources.
Comments on paragraph 7: I think I agree with the commentor, however I will
have to review the organic rules he mentions to say for sure.
>
>C. ENVIRONMENT
>
>1. Organic fish farms shall be managed to make optimum use of nutrients and
>
>minimize waste. This can best be accomplished by creating diversified fish
>farms, including more than one species and recycling freshwater aquaculture
>
>effluents into cropping systems. If aquaculture effluents are not recycled,
>
>farmers must employ practices to prevent the discharge of wastewater
>containing excessive levels of nutrients (e.g. constructing settling ponds,
>
>etc.)
>
>2. Water used in fresh water farms must meet EPA water quality standards
>and
>must be monitored daily for ideal environment (e.g. ammonia, nitrate &
>oxygen
>levels, salinity, pH etc.)
>[We may want to specify water quality standards more specifically and add
>quality standards for saltwater farms]
>3. Stock densities shall be limited to 10 kg of fish per cubic meter of
>water.
>4. When predator control becomes necessary, only non-lethal means shall be
>used.
>5. All pipe lines, tanks and water reservoirs shall be free of lead (Pb),
>impregnating materials, or other substances which have the potential to
>harm
>fish, humans or the environment.
>
>Comment:
>Items 1 through 5 represent micro-management of organic aquaculture and
>should
>be removed from the Draft Recommendation. Stocking rates have not been
>applied to any other livestock and to retain consistency should not be
>applied
>to aquatic livestock. Organic aquatic producers as all organic farmers
>must
>conform to governmental regulations related to producing food products.
>There
>is no need to further detail those requirements, but at the most only to
>state
>certified organic farmers must conform to all government regulations.
>
>
1. I agree with the commentor that this is micromanagement. Effluent
should meet EPA regulations for discharge.
2. Does this refer to water coming into the system or water in use in the
system? Do they mean EPA water standards for potable water or discharge
water? Water in a recirculating system will often exceed standards for
potable water, sometimes even discharge water with regards to nutrients.
If they are only referring to toxins like kepone, mercury, dioxin, lead,
etc.
then I agree, else???? This needs more clarification.
3. and 4. This is micromanagement also.
5. I disagree with the commentor. This needs to be stated. To the best
of my knowledge, there is no regulation with regards to lead piping, solder
etc. used for a purpose other than potable drinking water. Merely stating
that it must conform to government regulations will not prohibit lead usage
in aquaculture systems.
>D. ORIGIN, BREEDING OFffFOCK-
>1. Organisms that have been genetically manipulated (e.g. triploiding,
>gynogenesis, etc.) or that have been subjected to hormone treatment are
>prohibited.
>
>Comment:
>Item 1, above, states the general requirements for the production of
>"organically produced" livestock products found in OFPA and should be found
>as
>general statements in the USDA/NOP's Final Rule. They do not need to be
>reiterated herein.
>
>2. Fish stocks (eggs, hens, parrs, smolts, etc.) shall be sourced from
>certified organic fish farms. If organic stock is not available, stock may
>be
>procured from conventional farms provided that they meet the requirements
>under D 1 of this section and that two thirds of their lifespan is under
>organic management.
>
>Comment:
>Allowing one third of the lifespan of aquatic livestock from which
>"organically produced" products are derived to not be under organic
>management
>nor organically fed is inconsistent with OFPA and the NOSB recommendations
>for
>raising of organic livestock. Aquatic livestock should be treated similar
>to
>poultry, having to be raised under organic management and fed "organically
>produced" from the day old status.
>
>3. Mutilation is not allowed, including for the purpose of inducing
>reproduction (e.g. eyestock ablation in shrimp)
>
>Comment:
>Consistency in organic livestock production standards should be practiced
>here. "Mutilation" by tail docking, ear tagging, caponizing, branding,
>castrating are allowed in organically fed livestock. Why prohibit
>mutilations
>only in organically managed aquatic livestock.
>
1. I have a problem here. It is greatly desirable for aquaculturists to
use all-male populations. I don't think hormone treatments to induce
all-male populations are quite the same thing as adding hormones to increase
milk production. If the hormones added to induce male populations are not
present at harvest, they should be allowed. Stock genetically altered to
produce all male offspring should also be allowed. I don't think either one
will effect the wholesomeness of the harvested product.
2. I agree with the comments that stock should be from an organic source.
3. I agree with the comments that this represents a double standard.
>E. HEALTH CARE
>1. As in any organic system, health in aquaculture systems shall be
>maintained
>principally through prevention. Biosecurity measures to prevent the
>introduction of disease from the wild (and vice vets) shall be required.
>2. The routine use of any synthetic chemical substances, hormones, or
>antibiotics is strictly prohibited. If such have to be used as an emergency
>
>for disease control, the treated fish must be sold as non-organic. Natural
>vaccines and natural immunostimulants (e.g. yeast, fungi, etc.) are are
>allowed.
>3. Hydrogen Peroxide, sodium chloride, quicklime or potassium permanganate
>are
>allowed for parasite control.
>
>Comment:
>The first sentence of item 2 above speaking of subtherupeutic use does not
>need to be restated as these details are stated in OFPA as applicable to
>all
>livestock. The second sentence of Item 2 speaks to thereuputic use of
>medicines, and does not take into consideration the OFPA National List
>petition process for the use of livestock medicines. It would be a
>violation
>for the USDA/NOP to outlaw a standard or process that is mandated to take
>place under OFPA.
>
>Item 3 substances, if natural, are all allowed unless prohibited on the
>National List. All synthetic parasiticides must be petitioned, reviewed,
>evaluated and included on the National List by specific use or application
>in
>aquatic and all livestock.
>
>Both 2 and 3 should be removed from the Draft Recommendations.
>
I agree with commentor except that the verbiage should reiterate what is
said in the Existing Organic Standard.
There is no mention of chemicals allowed to alter the PH of a system. Are
these considered subtheriputic and disallowed; or are these chemicals
necessary in keeping the fish in their proper habitat and therefore
required?
>F. HARVESTING
> 1. The killing procedure shall be as expeditious and stress free as
>possible.
>Methods such as concussion, carbon dioxide, electrocution, etc. may be used
>as
>appropriate to the species. Water temperature should be gradually lowered
>to
>4 degrees centigrade prior to killing.
>
>Comment:
>What is the reasoning behind reducing water temperature to 4 degrees
>centigrade prior to killing? Is this the standard of the industry?
>
> 2. Fish processing must conform to all FDA regulations for fish and
>fishery
>products (Federal Register 60 FR 65095)
>
>added: A section on siting (suitable private lands, public lands, etc.) ].
>
I don't understand the need to chill the fish first. I know I read
something a while ago about certain animal rights groups trying to require
the chilling of lobsters, clams, etc. before cooking. I wonder if this has
something to do with that. You would not need to chill a tilapia or a red
claw to 4 degrees C to kill it.
Comments????
Wendy
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| Message 4 |
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Subject: Re: Live feed
From: "Sam Levy"
Date: Sun, 28 Feb 1999 23:13:51 PST
Brian--
Why not train them to dry feed? (I believe that there are suppliers of
bass pre-trained to dry feed--try Aquaculture Magazine for listings).
You don't mention the size of the fish. There are weaning diets for
marine finfish available (with very high protein & lipid levels) which
might be appropriate. Particle size should be approppriate to mouth
size--watch the fish, they should swallow the feed without struggle. In
general, it is better to feed a slightly undersized particle rather than
an oversized one. From the weaning diets, move to juvenile then growout
diets for predator fish (Salmon,Trout, Marine fish (D Labrax or S
Aurata), Hybrid Striped Bass, &c), then the matched grow-out diet. If a
soft-moist Salmon diet is easily available, your fish may prefer it to
fully dried diets. (This type of diet should be kept frozen until
use--get storing advice from the supplier or manufacturer.)
These diets are richer in protein & energy than Tilapia or Catfish
feeds. As a consequence, you will be adding more Nitrogen/gram fed to
your system and you should stock w/this in mind.
Back to live food, you might also consider Artemia if you will be
handling quite small fish. Cysts can be a bit expensive, but it is not
difficult to culture brine shrimp to adult size on yeasts, single celled
algae, algae paste (single celled) and other subbstances. Furthermore,
at any size above fresh hatched nauplii, they can be enriched
w/commercially available compounds.
I had some guidelines for the preparation of gelatin-bound, moist feeds
and will try to locate them if you're interested.
Good luck,
Sam
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| Message 5 |
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Subject: Re: Garden wall, peatcrete, bentonite and thorite
From: jilli and lars
Date: Sun, 28 Feb 1999 23:23:44 -0800
hi robin -
my comments inserted below -
Robin Jenkins wrote:
> flowing through my 500 gal aquapocics system within the next 6
> weeks. I'm having a little trouble finding a suitable grow media,
> but still working on it. All running totally off grid and on DC
> power. I will have some questions I'm sure and will want to run the
> final scheme and numbers by you all for your input, but for now I
> have some other questions pressing on me.
growing media - being an artificial rock expert, maybe you can help
me here. As an experiment, as a substrate I tried something known
locally as 'red rock'. It is usually sold as reddish-colored decorative
pebble, somewhat pumice-like in nature (very high surface area, porous,
lightweight). Do you know if this is a natural material, and if
so, where it is mined?
If not, does it's manufacture use or produce any substances
which i wouldn't want in my backyard or stomach? I try to keep that in
mind when i buy things, as all manufacturing plants are in somebodies
backyard, and whether they're aware of the risks or not, I'm somewhat
responsible by purchasing these products. I mean, hey, would you want an
epoxy factory in your backyard?
Otherwise, I might try it out, especially if weight is a
consideration. Does anyobody else have any experience with this
material? It is often used for growing orchids. I'd like to know if its
safe to use for edible vegetables. I don't see why not, but you never
know...
DC power- is this solar? I've only been working with solar
powered pumps for a short while, but I can recommend them for
hydroponic/aquaponics. They are highly suitable for such purposes as
they are automatically variable depending on the amount of sun - which
is exactly when plants need it. It really animates a system, binds it to
daily cycles and weather systems, and ties it to natural rhythms. Have
you noticed the same thing? Its probably one of the most appropriate
uses of photovoltaics yet. No battery storage or inverters necessary,
just a PV panel and a DC pump. Very simple and elegant.
--------------
> My homebuilt plywood aquarium sits in my living room and houses my
brooder colony of 10 tilapia. The tank volume is 110 gallons when
completely full. The biofilter is also homebuilt and so far everything
is going swimmingl:) Someone on this list > has mentioned their "garden
wall" for greywater treatment and it got me to thinking.....
----------------
You've brought up something I've always wondered about: Why is a
biofilter necessary with all those plants and gravel? Don't they serve
the same purpose?
Can anyone answer that question?
The creator of the GreyWaterGardenWall is Jorg Ostrowski.
I'm very happy my tinkerings might be of some help. I really
don't know what i'm doing, but the biological systems seem to be able to
work around my blunders!
I'm very much looking forward to more information from you as
you create and experiment with your system. All this feedback is
_invaluable_. We're really using the internet as it should be used. This
rules. What a ganglia!
Lars Fields
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| Message 6 |
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Subject: Re: Organic Aquatic Livestock Recommendations
From: "Sam Levy"
Date: Sun, 28 Feb 1999 23:31:36 PST
Wendy,
The chill before kill will prolong the shelf-life of the fish. Fish
headed for the fresh, chilled markets should be cooled to ~ 4 degrees C
as soon as possible--proper handling can add days to shelf life.
Sam
>>Methods such as concussion, carbon dioxide, electrocution, etc. may be
used
>>as
>>appropriate to the species. Water temperature should be gradually
lowered
>>to
>>4 degrees centigrade prior to killing.
>>
>>Comment:
>>What is the reasoning behind reducing water temperature to 4 degrees
>>centigrade prior to killing? Is this the standard of the industry?
>>
>
>I don't understand the need to chill the fish first. I know I read
>something a while ago about certain animal rights groups trying to
require
>the chilling of lobsters, clams, etc. before cooking. I wonder if this
has
>something to do with that. You would not need to chill a tilapia or a
red
>claw to 4 degrees C to kill it.
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| Message 7 |
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Subject: Re: Organic Aquatic Livestock Recommendations
From: "Wendy Nagurny"
Date: Mon, 1 Mar 1999 08:45:46 -0500
Ooohhhhhh, OK. I understand. Thanks, Sam. Is there an advantage to
chilling gradually as the STANDARD requires other than for the comfort of
the fish?
Wendy
>Wendy,
>
>The chill before kill will prolong the shelf-life of the fish. Fish
>headed for the fresh, chilled markets should be cooled to ~ 4 degrees C
>as soon as possible--proper handling can add days to shelf life.
>
>Sam
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| Message 8 |
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Subject: Chilling tilapia at harvest
From: Adriana Gutierrez
Date: Mon, 01 Mar 1999 08:56:46 -0500
Sam,
I thought that I read that the fish are less stressed thus easier
to handle and no resulting off-flavors if chilled.
Adriana
Wendy Nagurny wrote:
>
> Ooohhhhhh, OK. I understand. Thanks, Sam. Is there an advantage to
> chilling gradually as the STANDARD requires other than for the comfort of
> the fish?
> Wendy
>
> >Wendy,
> >
> >The chill before kill will prolong the shelf-life of the fish. Fish
> >headed for the fresh, chilled markets should be cooled to ~ 4 degrees C
> >as soon as possible--proper handling can add days to shelf life.
> >
> >Sam
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| Message 9 |
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Subject: Re: Organic Aquatic Livestock Recommendations
From: Dave Miller
Date: Mon, 01 Mar 1999 09:17:44 -0500
Wendy,
Your comments and opinions are well thought out and deserve praise,
however I could see an eyebrow rise for the following reasons:
"Stock genetically altered (fish) to produce all male offspring should
also be allowed."
I believe the line has been crossed as to what constitutes organic
farming techniques. While "all males" may be desireable you are
altering the general course of nature and this could be viewed as an
interuption, therefore not nature or not "organic". This is a cost
efficiency issue?
The chilling of fish might refer to a "natural" state of inducing
hibernation hence the fish "naturally" are in a sleep state and
therefore reduced of stress before dieing. I wonder if this would apply
to livestock?
Your comments are, otherwise, well founded, well thought out or worthy
of consideration. The fish folks will surely have more on what
constitutes organic, etc.
In a larger sense (not that I feel necessary to support this), playing
with nature by itself alters the means of organic, yet we all desire to
tweak nature through fertilization, artificial insemination or merely
seed selection.
I believe "organic" or even "farmed" are terms that deserve labelling
and standards are necessary. But I also believe they may ultimately have
limited use. Since I no longer eat fish, I could be wrong assuming that
some folks simply want to know a "safer" source so as to minimize
toxins - fish farming helps to alleviate uptake of mercury and other
metals/chemicals dumped into general waters and might be reason enough
to warrant an organic type label. But knowing a source does help assure
hence it come down to truth in labels. I wear one on my forehead, don't
you?
Jut kidding,
Dave
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| Message 10 |
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Subject: Re: Organic Aquatic Livestock Recommendations
From: "Wendy Nagurny"
Date: Mon, 1 Mar 1999 10:28:47 -0500
>Wendy,
>
>Your comments and opinions are well thought out and deserve praise,
>however I could see an eyebrow rise for the following reasons:
>
>"Stock genetically altered (fish) to produce all male offspring should
>also be allowed."
>
>I believe the line has been crossed as to what constitutes organic
>farming techniques. While "all males" may be desireable you are
>altering the general course of nature and this could be viewed as an
>interuption, therefore not nature or not "organic". This is a cost
>efficiency issue?
I thought about this issue a long time before taking a stand.
The mating habits physiological changes of many species produce undesirable
results when the species is being raised for food purposes. We routinely
castrate most mammals. Fowl can often be harvested before sexual maturity
becomes a problem, even then we often caponize the roosters. Many species
of food fish reach sexual maturity long before they are market size. This
greatly stunts their growth to the point of rendering a commercial business
non-feasible. In some species the age of sexually identifiable and sexually
functional is a very fine line, so hand sorting may not always give the
desired results. I think this issue goes beyond cost "efficiency". It can
mean the difference between having a business and not.
>
>The chilling of fish might refer to a "natural" state of inducing
>hibernation hence the fish "naturally" are in a sleep state and
>therefore reduced of stress before dieing. I wonder if this would apply
>to livestock?
>
At the temperatures the STANDARD requires, many of the species we wish to
aquaculture would not be hibernating, but already dead. Temperate
cold-blooded species whose physiology is designed to deal with cooler
climates will go into a state of lowered metabolism. I don't think
tropicals have such a mechanism for hibernation. They become quite
stressed. I know the way my tropicals behave when the heaters malfunction.
I think most of us have witnessed the erratic "shimmies" of chilled
tropicals. If we are chilling only for the psychological well-being of the
fish we must exclude tropicals from this practice. I feel that the chilling
of tropicals, especially the gradual, long, drawn-out process the STANDARDS
require, induces unnecessary "torture" for the fish and not the pleasant
drift off into la-la land the writers had in mind.
Wendy
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Subject: Re: Graywate /Wetlands/ EcoEngineering
From: jilli and lars
Date: Mon, 01 Mar 1999 10:59:48 -0800
Ted -
thanks a lot for those leads. I just called up the EPA and they're
going to check if they still have the constructed wetlands design manual. It
might be out-of-print as it's from 1988, but it sounds like a gem, especially
as its FREE.
and the National Small Flows Clearinghouse is at :
http://www.estd.wvu.edu/nsfc/nsfc_homepage.html
I just found it and i'm checking it out now, but it looks like a small mountain
of information!
thanks for all your knowledge.
lars fields
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Subject: Re: Graywate /Wetlands/ EcoEngineering
From: KLOTTTRUE
Date: Mon, 1 Mar 1999 15:05:17 EST
Fact: Ted is a walking,talking,reference library,and a nice one at that!
Thanks Ted
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Subject: Re: Food
From: KLOTTTRUE
Date: Mon, 1 Mar 1999 15:29:07 EST
Hello,I would like to here from anyone out there, Who's ever tried raising
fish on just natural feed? Worms,crickets, minnows,or just anything considered
natural? Instead of pelletized feed. Is it economically feasible? Also if I
were just keeping fish for the benefit of the plants, could I just get by on
natural feeds as far as nutrients are concerned to maintain healthy fish and
plants? Or do they need the additives. I know they survive in nature without
manmade foods.But does confinement in tanks or raceways,place any special
requirements in their diets to handle stress or any other problems that might
come up? Has anyone ever tried raising Bluegill Bream IN tanks. Thanks
Mr.Lott
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Subject: Re: Chocolate Hybrid
From: khale@ballistic.com
Date: Mon, 01 Mar 1999 15:45:20 -0600
Ken-ours is just a local market operation-selling to the people in our
local area. We have one large greenhouse where we grow tomatoes and 2
species of talapia. Ken----------At 08:54 AM 2/26/99 EST, you wrote:
>Hi Ken, What you say about the galvanized tanks is true,I just thought I
would
>tell him about it.I don't know if it would be economically feasible or not,
>but it would be a lot less labor intensive,and it could either be coated or
>have a liner. By the way do you raise Tilapia for food or to sell Fry and
>Fingerlings. I would be interested in hearing about your operation,that is if
>you don't mind sharing about it. Thanks Ken # 2
>
>
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Subject: Re: Chilling tilapia at harvest
From: Peggy & Emmett
Date: Mon, 01 Mar 1999 17:12:13 -0500
Sam,
What if you're so close to market that you don't care about shelf
life?....Emmett
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Subject: Re: Food
From: Gordon Watkins
Date: Mon, 01 Mar 1999 16:20:50 -0600
Mr Lott,
There's no reason that I can see that all natural feeds cannot be
used. I
use worms as a supplement for my breeding stock and would like to feed it to my
growout stock as well, but it would take lots more worms than I can currently
spare. I'm also experimenting with rape seed spouts which are high protein.
"Is it economically feasible?", you ask. That all depends on your
markets. If
you promote the fish as "organically grown" and "fed on unprocessed feed",
there's
a niche out there I'm sure.
What I doubt is economically feasible, whether you use natural feeds or
pellets, is keeping the fish on a maintenance diet simply to provide
nutrients for
the plants. Others may take me to task on this, but I seriously doubt
whether you
can justify the expense of maintaining fish vs. applying fertilizer. Also, the
amount of nutrients produced by the fish is in direct ptoportion to the
amount of
feed that is provided, so I suspect that if you were just feeding a maintenance
diet, insufficient nutrients would be produced plus your fish would not grow.
I've kept hybrid bluegill in my tanks with tilapia and while they are hardy,
they are slow growers compared to tilapia.
Gordon Watkins
KLOTTTRUE wrote:
> Hello,I would like to here from anyone out there, Who's ever tried raising
> fish on just natural feed? Worms,crickets, minnows,or just anything considered
> natural? Instead of pelletized feed. Is it economically feasible? Also if I
> were just keeping fish for the benefit of the plants, could I just get by on
> natural feeds as far as nutrients are concerned to maintain healthy fish and
> plants? Or do they need the additives. I know they survive in nature without
> manmade foods.But does confinement in tanks or raceways,place any special
> requirements in their diets to handle stress or any other problems that might
> come up? Has anyone ever tried raising Bluegill Bream IN tanks. Thanks
> Mr.Lott
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Subject: Re: Subduing nitrates and nitrites
From: Gordon Watkins
Date: Mon, 01 Mar 1999 16:35:52 -0600
What you describe sounds like a "coil denitrator", which is used ostensibly to
remove nitrates, the end result of nitrosomonas and nitrobacters. It is
basically a home for anaerobic bacteria which convert nitrate into nitrogen
gas. While I've never used one, I'm familiar with their use in reef tanks,
discus tanks, etc where high water quality is desired. They are tricky to
operate and of questionable value. If you're operating an aquaponic system,
using the S & S model or otherwise, it is counterproductive to remove nitrates
as this is a primary nutrient for the plants, whether they are in troughs,
beds, or rafts.
Gordon
Brian Gracia wrote:
> I have yet another question. I went on a net safari to find the ever
> elusive "information" about amonia, nitrates and nitrites. One of the
> links I came across involved using 50ft of 1/4" tubing to raise bacteria to
> change amonia to nitrates and nitrites and nitrogen gas. Has anyone done
> this for their tank systems? I know that S&S uses grow beds and this works
> for them, but I will be using troughs to grow veggies in.
>
> Brian
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Subject: Re: Organic Aquatic Livestock Recommendations
From: Gordon Watkins
Date: Mon, 01 Mar 1999 17:06:09 -0600
Wendy,
Thanks for your excellent comments on the pending legislation. I hope you
passed them along to the USDA.
Regarding your comments on genetic modification and all-male populations, I
think it will be a hard sell to allow hormones to be used for certified organic
production, residue testing notwithstanding. It's just too controversial an
issue. Besides, there are good alternatives available. I'm currently producing
all-male tilapia by crossing a hornorum with a mossambica or nilotica. It may
take more effort than methyltestosterone, but that's why consumers are willing
to pay a premium for organic foods. Don't confuse cross-breeding with "genetic
manipulation". If I was gene splicing a tilapia with say, a lightning bug, to
produce a glow-in-the-dark fish to make night time harvesting easier, then we'd
have a problem.
Regarding chilling before slaughter, while Sam's response concerning
improved shelf life is a good one, I suspect that this language in the Standard
was greatly influenced by the Humane Society, who is very involved in developing
the livestock standards. If so, it has more to do with humane treatment than
shelf life. I've seen similar suggestions for fish hobbyists to euthanize
hopeless cases: put 'em in the freezer before flushing. Personally I just bop
'em on the head ("concussion"). Tilapia are tough fish to kill. I've seen them
have 110 volts run through them for several minutes and still flop around. Maybe
chilling would help chill them out. I do agree that it's excessive to require
chilling prior to every method of killing.
Thanks again for taking the time to respond.
Gordon
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Subject: Re: Chilling tilapia at harvest
From: Gordon Watkins
Date: Mon, 01 Mar 1999 17:10:06 -0600
I thought off flavors in fish were due more to diet (certain types of algae in
particular) than to stress. I do know that mishandling beef cattle prior to
slaughter can cause a sudden surge of adrenaline which can produce off flavors
if it is not aged properly. Is the same true for fish?
Gordon
Adriana Gutierrez wrote:
> Sam,
>
> I thought that I read that the fish are less stressed thus easier
> to handle and no resulting off-flavors if chilled.
>
> Adriana
>
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Subject: new member--dumb question
From: "mjanes"
Date: Mon, 1 Mar 1999 22:15:40 -0500
Hello everyone
I am new to this group and fairly new to the world of aquaponics. For
several years I have been intriqued with the idea of starting a small scale
aquaculture system to supply my own family and maybe someday expand to a
more commercial scale. Time constraints of running my own woodworking
business and raising a family have always prevented me from doing any thing
more than dreaming. For the momment work is not demanding quite as much of
my time so I am upgrading my fantasy to the "maybe I could really do it"
stage.
My next problem is where. The building I have my shop in is a large
factory/warehouse with plenty of extra space. I have thought about setting
up some variety of closed system tanks in some of this space but the
required filtering system seems alittle daunting to a novice like myself.
For this reason the idea of a combination fish and hydroponics seems much
more sensible.(for other reasons also) Unfortunately the inside of a
warehouse is a hard place to put a greenhouse.
So now I come to my probably dumb question. In this warehouse is a dark and
chilly basement which no one uses. Has any one ever heard of growing
hydroponic mushrooms? If you could do it would they use the enough of the
right nutrients to work in an aquaponic system? Would there be different
bacteria present at the lower temperatures which mushrooms would require?
I will sit back and wait to hear from all you funcus lovers out there.
Marshall
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Subject: Re: new member--dumb question
From: William Evans
Date: Mon, 01 Mar 1999 19:30:39 -0800
mushrooms grow in wood
mj. Has any one ever heard of growing
> hydroponic mushrooms?
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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