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Re: Wild Daphnia

Not aware of any diseases carried by daphnia, however, they tend to live 
in places where the bacteria load is pretty high, so it may be prudent 
to hold them for a few days before feeding them to fish, to allow them 
to pass whatever they were feeding on.  Most of the problems from 
feeding wild daphnia are associated with catching other creatures along 
with the daphnia, such as dragonfly larvae, etc, that may be willing to 
eat fish.

Daphnia can be easily cultured and maintained by placing them in a 
child's wading pool filled with green water - you will get explosive 
growth and reproduction.  Daphnia are parthogenic - except when the 
population is getting ready to shut down, all dapnia are females and 
produce live young by parthogenesis (eggs do not need fertilization and 
are clones of the mother). In a population getting ready to shut down, 
some dapnia become males and mate with the females, producing eggs in 
little black egg cases that look like black pepper on the water.  These 
will hatch if subjected to freezing/thawing conditions.

To maintain daphnia cultures, you will need to harvest them regularly to 
avoid overpopulation.  If green water is in short supply, a yeast 
solution can be used as food.  Also,  adding vegetation (grass cuttings, 
etc.) can be used to produce bacteria that the daphnia will feed on.

Daphnia pulex will form eggs and cease reproducing in warm weather, 
daphnia magna (slightly larger) reproduces even in hot weather. Daphia 
may be shipped just like fish.  Also, if you can provide pounds of 
daphnia, you may be able to easily sell them to local pet stores which 
appreciate having live foods to sell their customers, or, alternatively, 
sell them to NFC members looking for live food or starter cultures.  A 
great live food, easily cultured, and all fish that I know of just love 
them. Shouldn't be used as a sole food source, as it tends to produce 
laxative effects, but is a great food to use along with flake, grindal 
worms, brine shrimp, etc.

>From owner-nfc at actwin_com Fri Aug 21 06:06:46 1998
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>Date: Fri, 21 Aug 1998 08:05:03 -0400
>To: nanfa at aquaria_net, NFC at actwin_com
>From: mbinkley at earthling_net (Mark Binkley)
>Subject: Wild Daphnia
>Sender: owner-nfc at actwin_com
>Reply-To: nfc at actwin_com
>I collected about three pounds of daphnia yesterday (for those who may 
>know, daphnia is a tiny freshwater crustacean that is often cultured as 
>live fish food).  I went for a hike along the Olentangy River yesterday 
>noticed brownish clouds of something suspended in the water along the 
>This area is just upstream of a low dam.  Right now the flow is very 
>and there was practically no current along this section of the river 
>Another interesting feature of this area is that the bank here is 
>of shale and gravel that are washed down by a small tributary stream.  
>tributary has some flow, but the water dissappears into the "delta" (is
>that an appropriate term?)  of shale and gravel and apparently seeps
>through into the river.  I could not ascertain whether there was 
>any outflow from the delta where the daphnia were observed.  Judging 
>the extent of the delta bank and the slight flow of the tributary, I 
>have to say that any outflow would be minimal.  Anyway, there were 
>clouds of daphnia all along the edge of the delta.  I could have easily
>collected 20 lb of daphnia if I wanted to.  I just used a fine mesh
>aquarium net to dip out the bugs, let them drain, and then dumped them 
>a bucket of river water.  I collected about three pounds in about 10
>minutes.  I took them home, dipped them out again, and put them in the
>freezer in ziplok bags.  Free fish food!
>So does anyone know of any diseases that might be transmitted by wild
>collected daphnia?  If not, this seems like an excellent way to collect
>live food for natives.  I have also observed thick congregations of 
>in a reservoir in a State Park west of here.
>Wonder if this stuff can be shipped frozen or live.  Anyone interested?
>Mark Binkley
>Columbus Ohio USA          <))><
>mbinkley at earthling_net
>Give a man a fish and you feed him for a day; teach him
>to use "the Net" and he won't bother you for weeks.

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