Re: Artemia

["Mcdaphnia at msn_com" <Mcdaphnia at email_msn.com>]

 > Careful, green water is a very broad term. One must check that the
culture
> contains unicellular green algae and diatoms, otherwise the algae [are]
too big
> to be ingested by the nauplii and/or the algae might clog up the
developing
> thoracopods on the nauplii.

Certainly true! I have had "contaminated green water" cultures that Daphnia
and rotifers cannot clear. On the larger Daphnia the green seems to grow
right over the Daphnia. I've associated it with feeding Spirulena algae
powder, but that could be coincidence. The only cure I've found for this so
far is to have multiple cultures and discard any contaminated with this kind
of algae, washing all equipment from that culture in a strong bleach
solution.
>
> Rotifers are too big to be eaten even by adult brine shrimp and are
superior
> feeders compared to brine shrimp, i.e. they clear the water of algae
before
> the brine shrimp do.

I agree that rotifers clear green water much faster than baby brine shrimp
do. I have protected my marine green water by adding the hydroid stage of
Cassiopea which clears the water of rotifers and allows the unicellular
algae to get very dense. Otherwise the rotifer population explodes until the
green water is consumed, while the brine shrimp have a relatively stable
population. I can add some brine shrimp to the green water to keep the
hydroids fed after the rotifers are eaten, and not see any decrease in the
green water. I would have thought that the brine shrimp could eat the
smaller rotifers. They seem so small and they seem to disappear when added
to a hatching jar of brine shrimp eggs. Any ideas where they go?

> What is the value of Artemia nauplii?
> Their nutritional profile indeed is so-so, but what makes the nauplii
stand
> out is their wriggling way of swimming which acts as a powerful feeding
> response for fish fry. Another overlooked fact is that fish fry are
thought
> of to make advantage of the nauplius' digestive enzymes as most fish fry
> have a very weak digestive system when being so young.
>
> Freezing: is the other viable alternative. Follow Wright's guidelines and
> pre-chill the plastic bags and tap water. The speed of freezing is the key
> to success.
 Some really good points! I have heard the digestive enzyme theory before,
but it seems very logical. I have also heard the theory that the small
amount of salt that may be still inside the brine shrimp helps to swell the
digested brine shrimp with absorbed water and make it possible for the fry
to eat a larger meal the next time. Is there any truth to that or is it an
old fishwife tale? How could this be experimentally determined?

> is it ok to use the brine solution in which previously brine shrimp raised
> to adulthood or I have to make new solution every time for raising baby
> brineshrimp to adult brineshrimp
 I may not be able to notice a slight change in using a brine solution
twice, but certainly there is a change after that, so a new brine solution
each time seems reasonable.  I think the achives mention something excreted
by the hatching brine shrimp that degrades the water quality. Certainly any
brine shrimp that perish after hatching or any eggs containing dead matter
would degrade the water quality too.

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