Aquaponics Digest - Fri 02/06/98
Message 1: Re: response to animal-waste aquaculture
from "H.Doelle"
Message 2: Missouri Aquaculture Association Annual Meeting (expecting
fish farmers and aquaculturists from Missouri, Kansas, Oklahoma and
Nebraska)
from S & S Aqua Farm
Message 3: Squash
from S & S Aqua Farm
Message 4: Hot water system
from S & S Aqua Farm
Message 5: Re: algal nutrition for tilapia
from John Shannonhouse
Message 6: Re: algal nutrition for tilapia
from james.rakocy@uvi.edu (James Rakocy, Ph.D.)
Message 7: Fwd. Re: Aquaculture Conference
from S & S Aqua Farm
Message 8: Re: Squash
from Chad Kruger
Message 9: Re: Hot water system
from Chad Kruger
Message 10: [Fwd: Training melons - part 1]
from Gordon Watkins
Message 11: [Fwd: Training melons-Part 2]
from Gordon Watkins
Message 12: [Fwd: Training melons - Part 3]
from Gordon Watkins
Message 13: [Fwd: Training melons Part 4]
from Gordon Watkins
Message 14: [Fwd: Training melons - Part 5]
from Gordon Watkins
Message 15: Re: [Fwd: Training melons - part 1]
from S & S Aqua Farm
Message 16: Re: [Fwd: Training melons - part 1]
from Gordon Watkins
Message 17: Re: [Fwd: Training melons - part 1]
from JCurts2318@aol.com
Message 18: Re: [Fwd: Training melons - part 1]
from ryarnell@orednet.org (Richard Yarnell)
Message 19: List suggestions
from S & S Aqua Farm
Message 20: Re: algal nutrition for tilapia
from Jack Rowe
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Subject: Re: response to animal-waste aquaculture
From: "H.Doelle"
Date: Fri, 06 Feb 1998 21:45:37 +1100
This is not quite correct. There exist more anaerobic digestion units in the=
poor countries than in the developing world. I have to qualify that, as I=
mean small units. This is the problem these days, engineers can only think=
big and large and not small. Joke aside. Countries like Bangladesh, Fiji,=
China, Vietnam all are building anaerobic digester units ranging from=
family size (6 m30 to industrial farm size ( 2000 m3; to handle cow manure=
from dairy cattle). It is very cheap. You can build a digester from=
polythene tubing. This has all been proven and successful. I strongly=
believe why it is not done, because *it is an old technology*. I can=
certainly provide you with articles from our Danish experts Frands Dolberg.=
He just send me via URL an article on *The introduction of low-cost=
polyethylene tube biodigesters on small scale farms in Vietnam* It appeared=
in *Livestock Research for Rural Development Volume 9(2),1997* He outlines=
that the price of a family size (5.1 m3) concrete digester installed costs=
180-340 US$, and the polyethylene digesters cost around 5 US$/m3. Do you=
call this expensive ??
With this I cannot agree more. However, health MUST have first priority=
over economy !
Horst Doelle
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Subject: Missouri Aquaculture Association Annual Meeting (expecting
fish farmers and aquaculturists from Missouri, Kansas, Oklahoma and
Nebraska)
From: S & S Aqua Farm
Date: Fri, 06 Feb 1998 09:13:02 -0600
Reprinted from the West Plains Daily Quill 2/4/98:
Jefferson City - Fish farmers and aquaculturists will gather in Springfield
in March to learn about the latest techniques in fish production and view
the newest equipment and technology available in aquaculture.
The Missouri Aquaculture Association's annual meeting is scheduled for March
5 and 6 at the Holiday Inn North. The event is expected to draw fish
farmers and aquaculturists from Missouri, Kansas, Oklahoma and Nebraska.
The combined meeting will provide a forum for discussions about producing
new species, such as hybrid sunfish, crappie, hybrid striped bass, walleyes
and much more. This year's meeting is sponsored by the Missouri Aquaculture
Association, the Missouri Department of Agriculture, Southwest Missouri
State University and University Extension.
"This combined meeting is a first and should be of great interest to anyone
now in the business or those interested in investigating the aquaculture
business," said Joyce Breedlove, president of the Mo. Aqualcuture
Association and owner of Mtn. Springs Trout Park in Highlandville.
Aquaculture - raising fish for food, bait and ornamenal uses - is a growing
industry in Missouri. The state's 75 fish farmers annually produce about
$30 million in sales. Another $75 million is generated through sales of
feed and other goods.
For more information about the meeting contact Chuck Hicks, Aquaculture
Specialist, Mo. Department of Agriculture, Market Development Division, P O
Box 630, Jefferson City, MO 65102, call 573-526-6666, or e-mail at
----------------------------------------------
I would think that even those from Arkansas or other states would be
welcome. Don't yet have a schedule of the two days or costs. Perhaps Chuck
can provide this for us.
BTW - Tom will be presenting a session on aquaponics at the Minnesota
Aquaculture Association meeting Friday February 27 - The conference will be
Friday and Saturday, February 27 and 28 in Willmar, MN. Perhaps Ralph
Anderson can provide more details on this meeting.
Paula Speraneo
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: Squash
From: S & S Aqua Farm
Date: Fri, 06 Feb 1998 10:05:50 -0600
At 04:26 PM 2/5/98 -0800, Chad Kruger wrote:
>>Have you considered utilizing a trellise system to grow your melons or squash.
>>I don't know if it will work very well in your system, but it is great in our
>>gardens. We "suspend" all of our melons in the air using nylon stockings. It
>>allows more space for more plants, keeps down disease and rot problems, and
>>makes the melons and squash perfectly shaped (more marketable). The other
>thing we do when we have space considerations for any type of vine crop is that
>we grow them on the edge of our growing area, and let the foliage and the ruit
>spill over the edge, providing more room in the growing area for roots. These
>are some of the "intensive" tricks we use in our "ecointensive" technologies.
The plants I was attempting to produce were a bush variety, probably not the
best suited to intensive production, but certainly an interesting trial.
How, specifically, do you suspend your melons? Sounds like a wonderful way
to reduce the space required, plus probably aided in keeping insects
fromdamaging the melons.
When you grow on the edge of the "growing area", how does this growth affect
your aisle/work space? I've had watercress produce this way, but have to be
certain to keep it harvested, or there's no room to move around the beds.
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: Hot water system
From: S & S Aqua Farm
Date: Fri, 06 Feb 1998 10:09:50 -0600
At 04:26 PM 2/5/98 -0800, Chad Kruger wrote:
>
>p.s. I entered our greenhouse this morning to see our 325 Tilapia floating on
>the top of our tank. The thermostat on our hot water tank never turned off
>last night. So we have poached fish. Oh well, at least it wasn't our dinner.
Sorry to hear about your fish.
We're always interested in ways to warm the tank water for the winter
months. Could you explain a little about your system. Is it set up to
automatically add hot water from a regular hot water heater? Is it a boiler
with a thermostat to add when water in the tanks reaches a certain level?
Tom's been experimenting with thermal siphoning panels, but we're always
interested in systems that work (well at least most of the time), and would
enjoy hearing about yours.
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: algal nutrition for tilapia
From: John Shannonhouse
Date: Fri, 6 Feb 1998 10:35:29 -0600
Hello,
On 5 Feb 1998, James Rakocy wrote:
<>
A prediction of this hypothesis is that dried algae (or plants)
should produce higher rates of growth than fully hydrated algae. To your
knowledge has anyone tried this experiment? The reason I'm asking is that
I'm working on a mariculture system where algae would be cheap relative to
common feeds due to the location of the facility and growth conditions for
algae.
John Shannonhouse
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Subject: Re: algal nutrition for tilapia
From: james.rakocy@uvi.edu (James Rakocy, Ph.D.)
Date: Fri, 6 Feb 1998 13:01:43 -0400 (AST)
Usually the feed conversion ratio for wet aquatic plants, including
filamentous algae, is in the range of 20 to 30:1. On a dry weight basis I
read recently the feed conversion ratio of filamentous algae is 2:1 for
tilapia, but I don't know what the growth rate was. I'm not sure if total
drying would alter the quality or palatability. Maybe partial drying would
be best. Seems like a good and relatively easy experiment to attempt. What's
the amino acid profile of algae? I'm sure it varies. How does it compare to
the amino acid profile of fish meal. Is there a fish nutritionist in the house?
I forgot to mention that in commercial production, growth rates are
secondary to the bottom line. It could be that a 1 g/day growth rate is
better than a 5 g/day rate if very low inputs make the low growth-rate
system more profitable. The problem with high tech recirculating systems is
that the inputs are too high so that profits are meager or nonexistent. That
could be where an intermediate level of technology, coupled with hydroponic
plant production, comes in.
Jim Rakocy
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Subject: Re: Squash
From: Chad Kruger
Date: Fri, 06 Feb 1998 09:39:17 -0800
>
>> The plants I was attempting to produce were a bush variety, probably not the
>> best suited to intensive production, but certainly an interesting trial.
>> How, specifically, do you suspend your melons? Sounds like a wonderful way
>> to reduce the space required, plus probably aided in keeping insects from
> damaging the melons.
>
I think that I came across this idea in some information from Jeff Ball, an
organic
gardener here in the Seattle area. The idea is to insert the melons or
squash or
whatever into the nylon (leaving the stem reaching out of the nylon of
course) and
then tying it to the trellis so that it can hang down. As the melon grows
the nylon
stretches around it. Depending on the construction of the trellis it makes it
possible to suspend all of your melons or squash on the trellis at different
heights. That is also one method of avoiding plants in your aisle.
>> When you grow on the edge of the "growing area", how does this growth affect
>> your aisle/work space? I've had watercress produce this way, but have to be
>> certain to keep it harvested, or there's no room to move around the beds.
If you can keep it harvested, that will work. We also deal with a lot of
beds. In
our African project we have our beds lined up side to side (I think we
created 80 or
so 100 sq. ft. beds this year). They are about 4 feet wide, so we allow
crops to
grow into every other aisle, leaving one to walk down and work on the beds
on either
side.Chad Kruger
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Subject: Re: Hot water system
From: Chad Kruger
Date: Fri, 06 Feb 1998 09:47:09 -0800
>> We're always interested in ways to warm the tank water for the winter
>> months. Could you explain a little about your system. Is it set up to
>> automatically add hot water from a regular hot water heater? Is it a boiler
> with a thermostat to add when water in the tanks reaches a certain level?
>
We actually have two thermostats: one on the tank, and one on the "regular" hot
water heater. The one on the tank we have had set on about 76 degrees (we
aren't
teaching aquaculture this term, so we were only holding the fish). The lowest
setting on the water heater is 90 degrees. So, the water from the heater
pumps in
at 90 degrees in order to maintain the tank temp. of 76. It is a 2500
gallon tank,
so it isn't as though the 90 degree water pumping in is making a great
temperature
difference. My best assumption is that it turns on about every 15 minutes
during
the winter time. We have never had any problems with temperature
fluctuation until
two nights ago. When I came in, the water was at about 97 degrees and on
its way
down. We have yet to look at the thermostat or sensors on the water heater
to see
what went wrong. Will update you when we get a chance. Unfortunately,
classes go
on, and we have to maintain the status quo while trying to fix problems.Chad
Kruger
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Subject: [Fwd: Training melons - part 1]
From: Gordon Watkins
Paula,
Here's a series of emails from my files on melons that might be useful.
Gordon
ianw wrote:
>>
>> Somewhere on the net, I don't recall where (perhaps here), I came across
>> the description below on how to train melons and cuberts to a vertical
> wire.
Here (in 5 emails) is a pictorial description of training (greenhouse)
melons taken from a British Royal Horticultural Society handbook on
fruit and vegetable growing.
1- Before planting, stretch wires across the sides of the house at 12
in. intervals and 15 in. away from the glass. Tie in two canes per
plant, one from the soil to the eaves, the other from the eaves to the
ridge. (First attachment).
2- From February onwards plant seedlings raised in a heated greenhouse
15 in. apart with the top of the root ball 1 in. above the surface. Do
not firm. Maintain at 16 degrees C. Damp down the paths. (Second
attachment).
--
Amr
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Subject: [Fwd: Training melons-Part 2]
From: Gordon Watkins
Date: Fri, 06 Feb 1998 13:04:07 -0600
3- Tie the cordon stems to canes. Pinch out the growing point at 6 ft.
Tie in laterals to the horizontal wires. Stop each lateral at five
leaves.
--
Amr
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Subject: [Fwd: Training melons - Part 3]
From: Gordon Watkins
Date: Fri, 06 Feb 1998 13:04:51 -0600
4- Pinch back resulting side-shoots to two leaves beyond the flower.
During pollination and as the fruits begin to ripen, open the
ventilation fully. Maintain a drier atmosphere.
--
Amr
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Subject: [Fwd: Training melons Part 4]
From: Gordon Watkins
Date: Fri, 06 Feb 1998 13:05:19 -0600
5- When the melons are the size of walnuts thin the fruits to four of
the same size to each plant by pinching off the others. Water generously
and give a liquid feed every 7-10 days.
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Subject: [Fwd: Training melons - Part 5]
From: Gordon Watkins
Date: Fri, 06 Feb 1998 13:05:48 -0600
6- Support each fruit with a net sling tied to the roof rafters or wires
once the melons are the size of tennis balls.
>
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Subject: Re: [Fwd: Training melons - part 1]
From: S & S Aqua Farm
Date: Fri, 06 Feb 1998 13:39:24 -0600
At 01:02 PM 2/6/98 -0600, you wrote:
>Paula,
> Here's a series of emails from my files on melons that might be useful.
> Gordon
Return-Path: hydro-errors@lists.best.com
>Received: from lists1.
Gordon - appreciate the effort - I can probably convert the two attachments
to this post, but the others are completely garbled, and I have not enough
computer knowledge to know how to make them legible. All I have are four
very large files with code. Anyone have any ideas?
Paula
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Subject: Re: [Fwd: Training melons - part 1]
From: Gordon Watkins
Date: Fri, 06 Feb 1998 13:57:37 -0600
Sorry about that, Paula. I just forwarded some mailings I had recieved
some time ago. They bounced back to me in legible form. The problem is
probably the fact that they contain line drawings, which accounts for
the large size. I'm afraid I don't know enough about the problem to
offer any suggestions. Sorry for the confusion.
Gordon
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Subject: Re: [Fwd: Training melons - part 1]
From: JCurts2318@aol.com
Date: Fri, 6 Feb 1998 15:17:06 EST
Paula
These are mime files and need a decoder program to decode them. Search
for Mime. The programs are rather small. I use a simple one called Xferpro.
Jim
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Subject: Re: [Fwd: Training melons - part 1]
From: ryarnell@orednet.org (Richard Yarnell)
Date: Fri, 6 Feb 1998 13:17:11 -0800
I think we need a ruling from the listowner. Since this is a text based
list, encoded files (usually long) don't really belong here. They can be
sent to individuals who need the material instead of taking up space on x
number of servers.
I vote to keep the text list a text list.
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Subject: List suggestions
From: S & S Aqua Farm
Date: Fri, 06 Feb 1998 20:14:47 -0600
At 01:17 PM 2/6/98 -0800, Richard Yarnell wrote:
>
>I think we need a ruling from the listowner. Since this is a text based
>list, encoded files (usually long) don't really belong here. They can be
>sent to individuals who need the material instead of taking up space on x
>number of servers.
>
>I vote to keep the text list a text list
Richard -
I agree that the best way for all list members would be for those with
specific information in other than text files make a general announcement
stating a specific batch of information other than text was available on
request by private e-mail.
Attachments are rarely opened from a mail list at large due to the
possibility of viruses, etc. Therefore, most lists request that they be
sent only on request by the receiving party.
However, having made my own share of errors along these lines, I pass on
making rulings and simply suggest that this method be followed on the>
aquaponics list.
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: algal nutrition for tilapia
From: Jack Rowe
Date: Fri, 6 Feb 1998 21:30:57 -0500
I think the question of the usefulness of algae and animal manures in
aquatic systems depends very much on whether we are talking about
_intensive_ or _low-input_ systems, and on whether these systems are
aquaPONICS systems (dual plant/fish focus) or aquaCULTURE systems (fish
main focus). =
Algae are a vital part of _natural_ aquatic systems, being the main food
source for fry and many zooplanktons. However, algal levels are easily
overdone, in which case fish suffer poor metabolism, disease or even
suffocation (while algae oxygenate water during the day, they use O2
rapidly at night and can quickly cause depletion). Further, the biochemic=
al
oxygen demand of algae is seriously complicated by the very high stocking=
rates common in aquaponics systems. Few or no commercially-important adul=
t
fish naturally rely completely on algae for their dietary intake -- the
fact that most adult fish gain weight faster with supplemental food than =
on
algae alone is indisputable. =
Dr. Doelle's point of "antibiotics, hormones and/or other stimulants" in
commercial feeds is, to me, very much a valid concern. Tilapia can be
>supplementally fed with a variety of natural waste products, including be=
er
and grain mill wastes, bran, cottonseed meal, etc. Also his point that "t=
he
fish response to feed is...complicated" is very true -- feeding is
influenced strongly by temperature, dissolved oxygen, pH and other factor=
s.
The need for supplemental aeration in a tank 'choked' with algae is no
coincidence, for instance, and one direct result of low O2 is slow feedin=
g,
poor food metabolism and low weight gain. Also, algae in natural systems
are part of an entire complex of inter-related elements (zooplanktons, fr=
y,
insect larvae, etc). A single element taken from a natural system and
isolated from related elements can create pollution from what would be a
resource. =
Dr. Rakocy's point that production costs in constructed aquaponics system=
s
may force some level of intensive management (ie, supplemental feeding) t=
o
raise cash flow to cover fixed overhead is cogent. I'm not sure that
thorough cost/benefit analyses have been done for all the elements of the=
se
systems, for instance costs of various foods vs fish weight gain vis-a-vi=
s
the large fixed overhead. Aquaponics systems as a whole can more than pay=
for themselves, though. At the same time, as Paula has mentioned, high
veggie profits basically pay the way for the less-profitable table fish
produced in many systems. =
This latter point -- that aquaponic veggie production is very
profitable/cost-effective -- is the crux of the algae issue in the contex=
t
of this list. Dissolved nutrients which feed algae (for a relatively smal=
l
profit in fish weight gain) could instead be used to feed vegetables whic=
h
bring a very high profit. In a system where the most valuable raw resourc=
e
is the fish's wastes, algae can reasonably be considered pollution, or at=
least a drain on resources. Algae's nighttime biochemical oxygen demand c=
an
also be unacceptable given the stocking rates used in aquaponics systems.=
=
Using manures, algae, composts, etc. have a cost-effective function in
natural aquaculture ponds (as does some moderate level of supplemental
feeding); I suspect that in aquaPONICS tanks, where veggies are a major
income, algae cost more in nutrient loss to veggies than they return in
fish weight gain.
I do think it is important to continue to consider the interaction of all=
these elements, and to study the different inputs from a cost/benefit vie=
w
(I'd like to see ecological costs taken into account here), or with a vie=
w
toward hybridization of technologies and/or food supplies, fry production=
,
etc. =
Jack Rowe
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