[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Live Foods Digest V2 #228

Hello John,

I agree with you, that many of the recipes for raising live foods are
partly "voodoo", because we don't know what is it that makes them tick! 

In absence of contrary evidence, I would assume that the directions are
honest, as far as *that* particular person's experience goes. Because
few, if any, conduct multiple reproducible experiments, it's mostly a
"one person's recipe" and many other conditions will produce same or
better results.

Many (most?) Daphnia in our latitudes (NY) produce *two* kinds of
ephippia: summer ephippia, when the water warms up too much for their
liking -- they hatch when conditions improve, and winter ephippia, that
normally need several freeze-thaw cycles to hatch. 

So, people's experience with ephippia can be, and probably is,
different, depending on exactly which critter, which local strain, and
which water conditions they have.



> Hi John,
> I just looked through that list of sites and though I didn't find anything
> new, I did find some things that bothered me - I hate it when sites that
> claim to be reliable and informative tell people how to look after
> daphnia or about their biology and the information is crazy. Commerical
> sites seem to be particularly guilty of this. For example Daelco claim
> that getting ephippia is the end of the world and that they'll never hatch
> unless frozen and thawed and/or heated up repeatedly. This really annoys
> me because it's just plain garbage. I've found that most of the embyros in
> ephippia will hatch within a 10 days if kept at around 72F in good daphnia
> water. This goes for magna and pulex (my two favourites). A certain
> proportion of the embryos take a lot longer to hatch and my guess is these
> are the ones which are triggered by freeze/thaw. This kind of information
> leads to people just throwing out a dead culture for no good reason.
> There were other foolish bits of advice amongst those sites (the main one
> that comes to mind was the no-water change advice on one of the commercial
> sites). Another site claimed that ephippia production had nothing to do
> with the presence of male daphnia. I often wonder how people think up this
> stuff :).
> John