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Light during hatching of bs
>From: ruddigar at home_com
>Subject: Re: Low bbs Hatch no light
>My first hatch was great! there was no light on the tank then, but
>like you say, the hatch rate has gone down. I leave a fluorescent room
>light on now. Do you think that will suffice? Or should I place a
>light directly over the hatch tank?
> I know it is recommended to use 2L pop bottles to hatch bbs, but I
>don't have a way of keeping them at a constant temp. over 70F. Would
>just placing these bottles in the heated tank work?
> Thanks for the help.
I do not have my library at hand right so I have to do this by heart. In
literature you can read that most Artemia strains need at least a short
period of light in order to break the diapause condition of the brine
shrimp eggs (cysts). One presumes that the light stimulus is responsible
for changing the structure of a haem-pigment located in the chorion
(=outer layer) of the brine shrimp egg. This certain pigment (exact
structure is not known yet) blocks some other pigments which need to be
activated by light in order to induce some intracellular changes (one is
not sure about what exactly happens) in the eggs which are mandatory for
enabling the cysts to break the diapause. Now, when brine shrimps are
being harvested and processed, they are being subjected to light; so one
might presume that these light stimula have been given to the brine
shrimp eggs. However, in the industry we still provide some light when
conducting Artemia hatching tests.
Do not spend too much time/energy on light but focus on temperature and
aeration instead. An optimal temperature of about 28 C (82 F) would be
best. The lower the temperature the longer it takes for the brine shrimp
to hatch. As you have to wait longer to get a decent yield, the brine
shrimp which hatched first are consuming their yolk reserves, hereby
lowering their nutritional value!
You can indeed hatch them “au bain marie” by submersing your hatching
cone or bottle in a warm aquarium (this takes a lot of light away so
provide some extra light, e.g. an 60 to 100W light bulb about 20 cm
away). I find this an easy way.
Also make sure to buffer your hatching medium. This is very important as
the baby brine shrimp secrete an enzyme (the gland is located in the
head region of the baby brine shrimp) during the hatching process which
helps them in breaking through the cyst shell. This particular enzyme is
most active at higher pH-levels, i.e. the enzyme can not perform its
function as well at lower pH-levels. So try to keep the pH high enough
(around 8 to 8.5). Important!
Keep all cysts suspended in the water column during hatching; provide a
moderate aeration as too strong an aeration will result in a lot of
cysts being “thrown” against the wall of the cone above the water level
where they will remain and consequently not hatch. Prevent too small air
bubbles as the emerging baby brine shrimp may stick to these bubbles
which may reside on the water surface.
I would also not use the hatching medium more than once as glycerol is
being released in the medium during hatching. This forms a perfect
substance for bacteria to grow on. These bacteria will also be present
on your baby brine shrimp and subsequently you introduce quite a lot of
bacteria into your fish tank!
Hope this will help you.
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