Date: 30 Jan 1998
From: Ernie White <ewhite@shelburne.nscc.ns.ca>
To: BRINE-L@UGA.CC.UGA.EDU
QUESTION:
My hatcher is a 17 litre conical type (obtained from Aquatic
Eco-systems, Inc.) and my eggs are Sweetwater Express (obtained from same place) and the food I have for them is Spirulina Algae-Feast fine size (20-80 microns).
My salinity is approx. 30-35 ppt. (Forty Fathoms instant ocean) at
a temp. of 28-30 degrees C. I use just enough aeration to keep the
eggs suspended. pH is 8.0-8.5 To sterilize the water, I use 21.9 ml
of Javex-12, bubble for 1 1/2 hours and then add 11.7ml of NA-THIO at 30% solution to kill the chlorine (this is in the hatcher).
The first problem I encountered was after the hatch. I turned off
the air and took out the stone and let everything set for 5-10 min.
then I let the unhatched eggs drain out and set them aside. I then
used a 183 micron screen to try to separate the egg shells from the
nauplii (instructions says to use 150-200 micron mesh size).
I found this didn't work for me because the screen just clogged
up (even by running water over the top of the screen with the egg
shells and nauplii on it). Is there a better or different way to do
this?
The next problem I'm having is what I should be using to grow them
out to an adult stage. I will be grateful for any information on any
designs of culture containments for my application (size, shape,
temperature, salinity, pH, etc.)
This brings me to stocking densities. What should they be and how
are they controlled? First of all, I'm using 10 tbsp. of eggs in 17
litters of water and I figure I'm getting 80%-90% hatch. Any idea how
many shrimp there should be in a batch like this?
Last of all, I would like to know what other things I can feed them
and at what rate. If everything goes right and I get these things to
grow, I'll probably be feeding them to trout fry. For this the
Artemia needs or should be around 45-55% protein.
Ernie White
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COMMENTS 1:
1. The optimum food size for Artemia nauplii is under 30 micron. There is a chance that your food selection could be too large and therefore starve the nauplii.
2. Temperature, salinity and aeration appear ok.
3. Why don't you decapsulate (chemically remove the chorion with chlorine) prior to hatching to save all the problems of separating unhatched cysts, shells and nauplii?
4. Easiest method is to have an aquarium with 30-35 ppt sea water (artificial ok) to which you have added Peters plant food or Miracle Gro or ??? and have strong light (gro-lux) above the aquarium. Aerate at a moderate pace and wait for the water to turn green. After the nauplii hatch you can rinse them and place them in the green water. Good idea to have additional aquariums or buckets of green water so that you can keep adding to your culture aquarium.
5. Aquariums, raceways etc all work fine for raising the nauplii to adults.
howard w. newman, BShrimp@aol.com
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COMMENTS 2:
For the both problems you have, here is how I do. First, I hatch the eggs separately from the culture. Second, I move the nauplii from the 'hatchery' to the main culture tank.
I have a 20L tank for the main culture (to grow the brine shrimp from nauplius state to adult to feed my adult discus fishes). In this tank I place a top of a small plastic bottle (0.5L water) upside down in the culture tank water to use the warm and the light of the culture tank. In this bottle I place two pinches of coarse salt with tap water, an air tube (without airstone) in the bottom and of course some eggs (the end of a knife).
The other day I remove the air tube from the little bottle and let the eggs stabilize. Then I use a clean air tube to syphon the nauplii from the small bottle to the main culture tank. After that, I just have to throw away the shells of this small bottle nose and repeat the process twice a week.
Two weeks after with constant light, the nauplii are adult and can be taken from the culture tank to feed the fishes. If you let the adults in the culture tank, they will start to generate eggs in their turn the third week.
Philippe LAVALLEE, plavallee@fedex.com