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Re: Daphnia Temperatures (LFD V2 #447)



On Sun, 30 May 1999 03:58:03 -0400 (EDT), Owner-Live-Foods at actwin_com
(Live Foods Digest) wrote:

>
>Date: Sat, 29 May 1999 23:01:00 +0100 (IST)
>From: John Clare <jpc at itintelligence_com>
>Subject: Daphnia Temperatures
>
>Although I've read a lot about Daphnia spp. over the last few years, I'm
>curious as to what temperature tolerances people have found for Daphnia
>_in practice_.
>
>I've kept Daphnia magna (for a few months last year. I'm currently tried
>to reaquire a starter culture) which I introduced to my pond last year but
>they didn't seem to do well and so didn't survive the winter (and Irish
>winter's rarely go more than 1/2 degrees below zero).
>
>I have great success with Daphnia pulex. It too was introduced to my
>pond and not only survived the winter but did so well that they number now
>in the hundreds of thousands (and they live with a lot of
>goldfish). It also seems to have a very high temperature tolerance,
>even doing very well in shallow black containers in the sun all day (I
>can't even begin to wonder how high the temperature of that water must
>get).
>
>If someone could tell me what they've found magna's tolerances to be, and
>how well it has done at those temperatures, I would be very grateful.

According to my experience - and some scientific literature - the
tolerance to temperature is quite similar. Despite a wide tolerance
both prefer 20C. D. magna did survive even in partly frozen
containers.  D. magna generally lives under more eutrophic conditions
and tends - in my outdoor containers in germany to overwhelm D. pulex
in well feeded black containers during the summer.

Additionally they should have survived the winter as ephippium. But
may be the greater speciesmen are more attractive to your fishes...

Stephan

-- 
Stephan Pflume
Abt. Vegetationskunde und Populationsbiologie
Wihlelm-Weber-Str 2. 37075 Goettingen