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[Killietalk] Inspecting killifish eggs in peat
Since there are many variables involved in the development of eggs
stored in damp peat, it behooves the good breeder to learn the difficult
process of finding and examining them for development. It also can cut
the legs from under the crook, when his feedback has your messages that
"he sent me no eggs in the peat." You cannot say that without
considerable confidence in your ability to find eggs.
In this note, I'll outline how I trained myself to find and inspect
eggs. It wasn't that easy, and it took some serious effort to get good
at it. The results are worth it.
Picking eggs from mops is a big help. The easily-seen eggs are good eye
training for seeing them in poorer-visibility peat. Finding eggs in peat
from prolific spawners, like GAR can also be a help. The eggs are big
and clear, and if there are lots of them, they are visible all over the
surface of the peat. Look at as many eggs as you can in as many
situations as possible. It trains your eye and brain to detect more
obscure spherical shapes where none should be.
I tried many ways, but my final, preferred technique, uses a shallow
white bowl and a halogen reading lamp. A light table is best, so
illumination shines through a thin layer of peat and eggs. If you
position a 50W+ halogen lamp across the bowl from you, the light shining
down is reflected from the white bowl through the eggs and thin peat,
much like a light table. A regular incandescent bulb is worthless, and a
fluorescent bulb even worse. You need a strong point-source of light to
make the glint from spheres obvious. Sunlight is quite good, but any
distributed light source makes finding eggs much more difficult. Use a
halogen reading lamp, about 45 degrees from the bowl bottom so light is
reflected right into your face.
Start by counting eggs in peat with known eggs. Drag a little peat
across the bare bowl bottom at a time, watching for the spherical shape
and (usually) amber color of peat-stained eggs. When you have counted
all the eggs in a small sample, count again. Confidence rises as the
counts begin to agree. Now you are ready to start the final training and
Boil and rinse a peat pellet, and dry to typical pipe-tobacco dampness.
Now, add exactly one small egg and mix well. Start a 10 minute timer,
and stop when you have found that egg or the timer goes off.
I repeated this training/test until I found the egg at least 9 times out
of ten within the ten minutes. At that point, I had some confidence in
my ability to find eggs in peat. At 75, my reading glasses are no longer
strong enough, so I use a jeweler's loupe or a head-band magnifier to
assist my vision. Use what you need to have your eyes and brain relaxed
enough to get really good at spotting eggs. Some young folks,
particularly those who are near-sighted, need no magnification. Others
have more difficulty with pattern recognition and need more practice,
better light or magnification.
Once eggs are found, judging development is pretty easy.
Clear eggs are undeveloped and have a ways to go.
Eggs with visible embryo are getting there, but may not be ready.
When the eye is developed and has a solid gold ring all the way around a
black pupil. it is ready.
My rule of thumb is when at least 2/3 of the eggs are in this latter
state, it is time to dunk them. Remove hatched babies from the peat in
no more than 2 days, using an eyedropper and gently stirring through the
peat from one end to the other to drive the hiding ones out to be sucked
up. Redry the peat and try again in 3 weeks or so. This depends on
species so know your species and if they have programmed variable hatch
times. Some SA annuals may need months.
Wright Huntley - 805 Valley West Cir., Bishop CA 93514
whuntley at verizon_net 760 872-3995. Cell 760 937-2276
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