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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
>
>Well,
>
>I collected about three pounds of daphnia yesterday (for those who may
not
>know, daphnia is a tiny freshwater crustacean that is often cultured as
a
>live fish food). I went for a hike along the Olentangy River yesterday
and
>noticed brownish clouds of something suspended in the water along the
bank.
>This area is just upstream of a low dam. Right now the flow is very
low
>and there was practically no current along this section of the river
bank.
>Another interesting feature of this area is that the bank here is
composed
>of shale and gravel that are washed down by a small tributary stream.
The
>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
actually
>any outflow from the delta where the daphnia were observed. Judging
from
>the extent of the delta bank and the slight flow of the tributary, I
would
>have to say that any outflow would be minimal. Anyway, there were
thick
>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
into
>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
daphnia
>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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