Artemia decap

Re: Artemia decap

Postby Matt1001 » Sun Aug 26, 2012 2:20 pm

hi guys great thread, i will be trying this very soon,

just cant quite get my head round the storage, some of you seem to be using plain salt water, and others highly salted whats the difference and reasons behind it?
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Re: Artemia decap

Postby rayjay » Sun Aug 26, 2012 4:01 pm

Because the cysts can HATCH and then live in an very extreme range of salinities, one needs to store them in saturated salt solution so they don't hatch when you don't want them to.
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Artemia decap

Postby Matt1001 » Sun Aug 26, 2012 5:03 pm

Ahh cool so the extra salinity will just stop them hatching, guessing kept in the fridge then.

How long will they keep like this?
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Re: Artemia decap

Postby rayjay » Sun Aug 26, 2012 5:53 pm

Don't know for sure but I've kept them for about 5 months one time when the jar got shoved back in the fridge and forgotten while I made up new batches thinking I was out.
I am no longer decapping the cysts but instead, just using bleach to sterilize them for a bit.
When decapped, I end up with a lot of debris in the water from the alveolar/chorion covering after the bleach does it's thing and I couldn't easily separate this crap from the decapped cysts. A lot of this crap transferred to the growout containers, causing the water to foul faster.
Now, I sterilize, hatch out, let sit for about 5 to 7 minutes and siphon off from the bottom, the unhatched cysts along with the hatched nauplii, leaving the top layer of empty cysts. Then, I let sit again and siphon most of the nauplii, leaving the unhatched cysts in the bottom.
Usually I replace the unhatched cysts in new water and let them hatch out over the next day or two and repeat the separation. If I'm feeling to lazy I just dump it.
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Re: Artemia decap

Postby Luis A M » Sun Aug 26, 2012 6:04 pm

Placing the decapped eggs in a brine solution dehydrates them again and in this condition they can be stored refrigerated.
But this is how I do it now.After flushing is over,I resuspend the decapped eggs in 1 l of 1.010 water with strong aereation in the inverted soda bottle.
Then I siphon with an airline hose into 9 100 ml vials.About 100 ml remain in the bottle.More water is added and that will be next day hatch.
The vials are kept in the fridge.I normally need half of each/day,so I have to decap every 19 days.Not bad 8)
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Re: Artemia decap

Postby Matt1001 » Sun Aug 26, 2012 6:29 pm

thanks guys
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Re: Artemia decap

Postby NemoMaker » Tue Aug 28, 2012 11:32 pm

I have seen decapsulated cysts stored in a super-saturated solution kept in the fridge are still viable after well over a year.
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Re: Artemia decap

Postby aquagrrl » Thu Aug 30, 2012 11:18 am

When you all decap, do you manage to get all the shells off? It seems like if I let it go long enough to get ALL the eggs off, there are a large number of "over" bleached ones that don't hatch out right and the water gets all nasty. If I let it go so 80%-90% are decapped and the left over 10%-20% are white (not fully removed) then the hatch seems to do okay. I was wondering if that is a normal experience or if there is a secret to decapsulating them all successfully.
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Re: Artemia decap

Postby Luis A M » Thu Aug 30, 2012 2:25 pm

Tami,with my protocol,all the eggs are decapped after 3-5 min.You can check them under the scope while under process.
Non hatching eggs are not over bleached but simply bad eggs,the % of which defines the quality of these eggs.But they don´t affect WQ and are readily consumed by fish.
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Re: Artemia decap

Postby aquagrrl » Fri Aug 31, 2012 3:33 pm

I don't know that's the case. When I bleach so that all the eggs are decapped, I get a lower hatch rate, and the water gets really "scummy" a few hours after starting a hatch. My assumption thus far has been that the eggs/nauplii are previously killed and falling apart in the water. But it's just that, an assumption. Whatever the case is, if I bleach until all the eggs appear decapped, I get a lower hatch rate and bad water. I'd love to hear your thoughts on what might be going on.
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Re: Artemia decap

Postby rayjay » Fri Aug 31, 2012 11:55 pm

I think the "Scummy" in the water comes from the soft shell remaining after the decapping procedure.
Anyway, that is why I stopped decapping as I was unable to separate that scum from the nauplii and the resulting culture ends up crashed after about 4 or 5 days when I transfer the nauplii to the grow out containers. With only sterilization instead of decapping, I don't have this problem.
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Re: Artemia decap

Postby aquagrrl » Sun Sep 02, 2012 3:29 am

I never had the scummy water issue if I only go to 80-90% of the total number decapsulated. They also grow out just fine so I don't think it is the soft shells that are causing the issue; at least in my case. Though it sounds a lot to me like you had the problem I did with "overprocessing" them.

Now that I'm reading all this though, I've got an idea. Next decapped batch, I'm going to do them as I normally do (with most, but not all decapsulated) then place in water and see if the still-shelled eggs float and the decapped ones sink. If that does in fact happen, I can either toss those eggs, or separate and see if I can further decapsulate. I may do that just because I'm curious if they will work at all.
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Re: Artemia decap

Postby Luis A M » Sun Sep 02, 2012 3:31 pm

Dissolved shells are flushed away in the process,could never be an issue :?
Try to follow exactly the protocols,so results can be compared.I do it all the time and always without problems.Same recipe should produce the same cake :wink:
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