CULTURING OF ARTEMIA BY AQUARIUM HOBBYISTS

Sent: 3 July 2001

QUESTION:

We keep brine shrimp cysts dry and cool at about 8°C. After 1 to 3 years the hatch rate is still good, perhaps better 50 to 75 percent.
But... we have the feeling that we have nearly no chance to raise them to adults. After at least one week the death rate is over 90 %. All parameters have been controlled, salt, food, phytoplankton etc.
We made different tests, the result was always the same.

Does anyone know whether the brine shrimps change over that long time of storage?

Gerd Voss

e-mail: webmaster@gerdvoss.de

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COMMENTS 1:

Did you check your water quality?

Paolo Villegas

e-mail: paolo.villegas@abs.pinoycentral.com

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COMMENTS 2:

I'm not sure what the problem is with your set up, but the 1 pound can of cysts that I bought from BRINE SHRIMP DIRECT, approx. two years ago, is still producing the same hatch rate as when I got it, and has the same end result for production of the adult Artemia as I started
with. I store mine in the refrigerator at around 4°C. I have occasional "crashes" or sometimes low success rate, but that is normally due to other circumstances, not due to the cysts or the age of the cysts.
I would like a higher success rate at the adult stage, but at close to 50%, it's better than most that I know of in the salt water aquarium
hobby.
After 3 1/2 to 4 weeks, they produce live young so I don't have to use a
lot of cysts on a continual basis. I can use a regular fish net to remove large adult shrimp, leaving the smaller ones to develop into
producing adults.

Ray Jay

e-mail: ray.jay@sympatico.ca

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COMMENTS 3 :

The water quality is important. I made the mistake to make
tests with different kinds of food for Artemia and increased the
phosphate value up to 2 mg/ltr. The population of adult Artemia
I had at that time decreased drastically. I could improve
phosphate to 0,7 mg/ltr in the meantime and there are some
young Artemia to be seen now. I wonder whether they will raise.

The 200 ltr. tank outside is kept at 26°C. Unfortunately the water always is clear, perhaps due to the fact that I can't get rid of Brachionus.

Gerd Voss

e-mail: webmaster@gerdvoss.de

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COMMENTS 4 :

A comment on your last remark.
"Perhaps we should not put cysts into water which is not
older tan a week or so ??"
I put the cysts in water from a 20g container with bio-balls, that has
been in circulation since last August 2000. The water is continually
used and recycled, with the only new additions being water for
evaporation losses, and new salt water to replace the water the cysts
are hatched in. Water the cysts are hatched in is disposed of after the
newborn are removed.

Another note re old water, I have a 20g tank that I was unsuccessful in
keeping brine alive in but kept trying on and off, using the same water
and after about 1 year, the tank now has a sustaining population of
brine shrimp in it. The biological filtration is aragonite, separated
from the brine shrimp by an acrylic sheet siliconed in place, with a
hole at one end, covered with plastic coffee filter material, and at
the other end is an uplift tube for air powered circulation. (UGF style)

I'll repeat my brine shrimp web page in case you want to see the system.

http://www.angelfire.com/ab/rayjay/brineshrimp.html

Ray

e-mail : ray.jay@sympatico.ca

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COMMENTS 5:

Personally, I have a small plastic bag of Great Salt Lake variety cysts in my garage. They've been in there for at least a year and a half. They have been kept dry, but the temperature hasn't been low or stable. The temperature in my garage ranges from around 15°C in the winter to 40°C in the summer, and can vary by 20°C per day in fall and spring. While their hatching rate isn't as good as it was when I first purchased them, without trying very hard I can still get what looks like a 50% hatch rate. This is just a guess though - I'm comparing the apparent amount of floating egg shells to the amount of unhatched eggs on the bottom of the container.

The hatch rate would have probably remained higher had I kept their
temperature lower and more stable, but hatch rates can be affected by many factors in addition to the age of the cysts. Once Artemia
are re-hydrated, their ability to withstand such temperature variations is
greatly reduced. While it's hard to prove, it appears that I've had entire
cultures crash when the water temperature varied more than 5°C.

The source of the cysts also apparently dictates the appropriate temperature range for rehydrated Artemia. For example, the Great Salt Lake variety appears to do well in water temperature of 20°C to 23°C. The San Francisco Bay variety appears to do well in slightly colder water, in the range of 15°C to 18°C. Thus, even though either type of cyst may be stored for years at relatively cool temperatures, the water temperature that the Artemia originate from should be duplicated to raise and keep the creatures!

Robert Manning
RobertM782@aol.com

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