[Killietalk] re:moina, Japanese daphnia

["Mach Fukada" <fukada at aloha_net>]

Aloha George,
    The napuli of the Moina I have are much smaller.  I think the sea grant
people at UH-Manoa did a study and found that they were from rotifer to
artemia napuli size.  I have also found the average size varies and is
inversly proportionally to to population density.  So in a very densly
populated culture they are a good bit smaller than well spaced ones.

It hasn't been to difficult to harvest napuli. I strain with a fine meash
nylon fish net.  It collectes most of the larger animals.  Then pass the
water plus small stuff through a brine shrimp net.  A good brine shrimp net
will also collect rotifers a bad one will not even collect artemia napuli.
The only disadvantage to this is that if you do enough of this in a given
culture you can depleate one age/size calss in the culture and have a slow
down in a few days.....  Aparently, they lay eggs which rapidly hatch or
eggs that go dormant depending on culture conditions....
MTF

Date: Sun, 02 May 2004 16:17:47 -0500
From: George Slusarczuk <yurko at warwick_net>
Subject: Re: [Killietalk] re:moina,  Japanese daphnia
To: killifish discussion list <killietalk at aka_org>

Hello Mach,

Some years ago you gave me a starter culture of your Moina. For a while
they were doing fine, but then I neglected the culture somewhat and lost
them.

As I remember, they were NOT as small as Bro. Paul describes these
"Japanese Daphnia" -- "a smidge smaller" than brine shrimp nauplii. That
would make them about 400 micron, or even smaller.

There ARE Cladocerans in that size range even in the US -- Bosmina
longirostris (400u); Alonopsis fitzpatricki (400u) Streblocerus
serricaudatus (200-400u); Alonella nana (200-300u); Alonella dadayi
(<300u), etc., but I don't know anybody who cultures them.

Does anybody on the list have these critters or knows who does?

Best,

George



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