Comment

Comment by Sue Whitney on June 17, 2014 at 1:15am

Hi, I am new to AP and am still learning before setting up my system but I did read that you can feed chicken poop to fish. I have a couple of chickens, worm beds and just got started on Duckweed so I am hoping between the 3 and some leafy greens I can get by without having to buy any fish food. Any thoughts?

Comment by TCLynx on December 16, 2013 at 4:37pm

Matt, they are not expecting the duckweed to be alive and growing anymore after freezing.  They are simply freezing it as a way of storing it to feed the fish at a later time.  Other people will dry the duckweed (which would be a more compact way to store large quantities) but again, you are not expecting it to be alive anymore after storage.    Will it be ok frozen?  Well I suppose it depends on how your fish feel about eating frozen food.  Some people think frozen veggies are great while others turn their nose up at anything but fresh.

Comment by Matt Rosso on December 16, 2013 at 2:01pm

I have read that some guys will press into a block and freeze their duckweed.  they will throw it in and the fish will eat it as it thaws.  I'm not feeling this, my duck weed goes away in the winter outside.  Will it be ok frozen?

Comment by Eric Warwick on May 11, 2012 at 7:16pm

One thing about the calculations I'll have to knit pick about: when you say 1g of NH3 will feed one square (meter?) of duckweed you're assuming a condition the duckweed is in. You'll have to find the equation for uptake and map the likely conditions, and so on. The way you'll have to do this is find the equations for conversion of mass in duckweed, and individually convert grams to moles, moles to grams and so on (unless you find a source that does that for you). Considering the work has already been done, you'll find the info' you'll need to achieve this goal--and you'll end up with a probabilistic answer. What you can do to present this estimate is use a box and whisker plot. I don't really have time to explain a box and whisker plot (if you need it) so keep the questions to my knit picking. Sorry, this is too complicated a quick calculation.

Comment by marty lininger on May 11, 2012 at 8:48am

I want to estimate the size of duckweed bed that a specified fish population can support.  Any feedback I can get on my assumptions validity would be greatly appreciated!  Perhaps there is a logic error in my steps to calculate the size, please let me know!

My final calculation below seems to be way too much.  I do not know where I am erring.

Assumptions:

fish incorporate 30% of protein in feed, the other 70% is converted to ammonia  (1)

can get 95 gram of ammonia from 1kg of protein fed    (1)

1 gram of ammonia will feed 1 SM of duckweed  (2)          

duckweed can double in 4 days or less

constant population mass 1000kg of tilapia,       FCR of 1.5

consumes 1500kg of 30% protein feed in 1 year, consumes 450kg protein

 450kg protein x 95g ammonia/KG protein  = 42,750 g ammonia

which can support 42,750 SM growth of duckweed

harvesting half the crop every 4 days = 365/4 = 90 harvests

42,750 SM / 90 = 475 SM growing area per 1000kg tilapia fish

 

Other:

1SM of optimal density duckweed weighs  0.1 – 1.2 kg (0.65 avg) wet and is 93% water (3)

1 SM of optimal density avg 0.65 kg wet duckweed weighs 45 grams dry

1 SM naturally occurring duckweed in Orlando, FL dried weighs 100g  (4)

 

ref;

(1)    http://www.fao.org/docrep/X5744E/x5744e0e.html

(2)    Kobus Jooste post

(3)    Various sources

(4)     Own observation -but was it optimal density?

Comment by marty lininger on May 3, 2012 at 9:39am

hello, my name is Marty Lininger.  i am new to this forum.  i live in central FL and i am trying to determine if i can market Tilapia Fish.  i know that there are many cost obstacles to that, one being feed prices.  i am keenly interested in growing my own food.  i am very aware of duckweed and i also wonder if i process my Tilapia myself and return the carcass to the food chain how that would impact the process.

Comment by Paul Trudeau on March 17, 2012 at 12:40am

I did the same with them, Carey, when I was was growing up in a suburb of Detroit, Michigan.  Nostalgic!

Comment by Carey Ma on March 16, 2012 at 11:36pm

Yes definitively three spined sticklebacks. I use to catch them in creeks near my place in Renton. I'm not sure they are good source of natural food because of their spines but they do breed well. I use to have them in my "natural" or "wild" tank. I know, I know...leave nature be. Guppies and mosquito fish are still my favorite feeder fish to raise.

Comment by Rick Stillwagon on March 15, 2012 at 8:47pm

I havent found what they are yet.  But they are able to keep their numbers up with a good deal of predators in my ponds. I havent seen them reproduce yet, so I brought a bunch inside to monitor in my aquarium.  Some of them look like they are ready to lay eggs.

Comment by Paul Trudeau on March 15, 2012 at 8:42pm

sticklebacks?

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