Scheel's Letters: Egg Development in Aphyosemion sjoestedti (continued)
courtesy of
ARK - Arizona Rivulin Keepers
The Scheel Letters, No. 37
Egg Development in Aphyosemion sjoestedti (continued)
10 Jan. 60: another 81 ripe or nearly ripe eggs removed.
12 Jan. 60: another 77 ripe eggs. In the bowl there are now 13 eggs with very
small but slightly pigmented embryos plus 92 eggs with transparent embryos or
no embryos.
16 Jan. 60: 14 ripe eggs removed.
19 Jan. 60: another 27 ripe eggs.
22 Jan. 60: another 30 ripe eggs.
24 Jan. 60: another 12 ripe eggs. In the bowl
only 21 eggs are left: 7 with small pigmented embryos (pigments can not be seen
with the naked eye), 14 with transparent embryos or no embryos. Of these, 10 were
sent to Wickler.
07 Feb. 60: small pigmented embryos in the last eggs.
That is to say that a
total of 392 eggs developed (Wickler's included) between 19 Dec. 59 and 07 Feb. 60.
Only 6 eggs were lost (fungus). 28 eggs were lost before 19 Dec. 59. If this data
is plotted into a diagram (days/eggs developed) you will have a curve, rather regular.
From this you may take the following information:
10% eggs developed after 58 days
20% eggs developed after 62 days
30% eggs developed after 67 days
40% eggs developed after 70 days
50% eggs developed after 71 days
60% eggs developed after 73 days
70% eggs developed after 75 days
80% eggs developed after 78 days
90% eggs developed after 83 days
100% eggs developed after 100 days
Temperature of 22-23 C was very constant (inner fishroom). The water was the
usual "rainforest" type. Storage was in one 2 liter plastic box with free entrance
of air. Frequent changes of water were made because of evaporation. Development
runs very quickly between the 60th and the 80th day. Compared with the scant
information on egg development in dried peat, this development did progress rather
fast. Foersch's results might be explained this way: during storage in slightly
moist peat the eggs did not get a sufficient oxygen supply and because of this
they were forced into the state of "resting eggs". However, after washing and
restoring, they got enough oxygen to finish the development within 4 weeks.