[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re:sex ratios
>
>At the beginning of the year, I did my grade 8 science project on the
>affect of pH on the sex of N. foerschi. I hatched a batch of about 40
>fry in normal tap water (approx. pH: 7.2, total hardness: 90 ppm).
>After a week, I separated half the fishes into water w/ a pH of 6.4 nd
>the other half into water w/ a pH of 8.4. (used sodium phosphate to
>lower pH and baking soda to raise it). The water in the lower pH tank
>had pH: 6.4, total hardness: 90 ppm. The water in the higher pH tank
>had pH: 8.4, total hardness: 90 ppm. I tested the water in the tanks
>every 4 days, and tried to keep the chemistry in the tanks from changing
>throughout the experiment. I "controlled" as many variables as I could
>think of, and everything I did to one tank of fishes was done to the
>other. After about 8 weeks, I counted 1 male : 19 females in the tank
>w/ the 8.4 pH. In the 6.4 pH tank, I counted 5 males : 14 females. If
>you take the results at face value, it means that the 8.4 pH produced a
>sex ratio of 1 male to 19 females, and the 6.4 pH produced a sex ratio
>of 1 male to about 3 females. Incidently, the males raised in the 6.4
>pH showed better colouring and more vigour. Just wanted to tell my
>experiences w/ the whole sex ratio thing.
>
>Anyways, hopefully the thing gets through. You know, first time posting
>and everything. BTW: I missed 3rd place at the science fair by .5%,
>nuts.
>
>Sam
I hope you would continue your project. Keep the fish in the same
type of water as they were hatched in. Spawn them and then see what
your fry ratio is.
Several years ago a young man from the local U. was going for his
Doctors degree. He got some Killies from me. He wanted them for his
theises. He was convinced that the sex was determined at birth, and
did not change after birth as sometimes thought. He stated that he had
proven that Swordtails that are often said to change from females to males
were actualy submissive males only developing later. I lost track of him
later and never did see his writings, or how to find them.
WD0FNU
Dale Deck
http://www.netins.net/showcase/killies/
Follow-Ups: