Ratio of male to female shrimplets

[ineke]

Hi all, just wondering if anyone notes the male to female birth rates. I have about 40 shrimplets from various females and it looks like the majority are boys. They are between 3 and 12 weeks old. Is there anything that affects the sex of shrimp.

Cheers

Ineke

[Heavyd]

Well it's interesting that you mention this. A while ago I received several messages that the yellow juvies I was sending off were all female. One guy bought 50 juvies in one go, and about 1.5-2 months later, requested some males as he had none amongst the 50 grown shrimp! I think it may be temperature related. At that stage I didnt have a chiller and my tank temperature was higher.

[ineke]

Well that cant be it i dont have a chiller and my temps were high! I had thought it was temp related too. Some are still a bit small to know for sure but a lot are definitely boys. when they get a bit bigger they can go and live in my fish tank. There are some good coloured boys- red cherries and 1 in particular is very nice but not a fire.

[BlueBolts]

The debate of the sexes / ratio is often discussed based on temp, PH and/or stress levels..... I've got no idea, BUT would love to know.

[ineke]

The tank I had mostly boys in was quite stable , ph 7.4, but temp was between 23 -27 as I don't have a chiller. I have now moved them all to a bigger tank which will be a more constant temperature. The TDS in small tank was around 470 but gradually brought down to 299 , the bigger tank is around 300 and ph 7.4 but this may change as I start doing RO water top ups. I will gradually take out the lighter boys and try to keep track of male to female ratio in this tank.

[Dean]

This topic always interests me :)

from my experience only, i have found that with

cherry shrimp,

if you want more girls you need to have a high PH 7.8-8.0 GH of 10-14

Crystal shrimp

if you want more girls you need Low PH 5.4-5.6 GH 4-6

I have not found temp plays a big part yet.

[ineke]

The temperature adds up as we both had higher temps but Heavyd had more girls while I had more boys. My ph stayed stable at 7.4 it came out of my pura tap at that and never changed in 3 months. I didn't have a gh and kh test kit but do now. I am taking readings fortnightly now unless there is a problem and I keep a ledger so it will be interesting what happens with this next lot of babies as there are a lot of berried girls . I will write this up again once I have an idea of what the shrimplets of these next batches are together with the readings if there is a change.

[emboli]

I have heard about the pH theory with cherries. Lower pH resulting in a larger male population ratio.

Am unable to prove it though.

Yo D! Maybe I should buy some of your yellow juvies to kick start my population!

[Aquathumb]

Very interesting topic! thanks for your in put dean I'll try slowly moving one of my cherry tanks up to 8pH and 13gH

[northboy]

It is a well known fact that Temp and PH will influence the Sex of offspring of most animals, Unfortunately it is different from Species to species.

From the Natives I have breed Temp will have an influence but PH has a stronger influence, lower more Male and Higher more female, I just can not work out at what range it changes, more records are needed and as I don't have any thing built yet it will be a while before I am able to again

Bob

[Robert]

I tend to get more males during the winter months when waters are cooler say 19 degrees compared to summer months when my temp flucs between 22-26

[ineke]

I tend to get more males during the winter months when waters are cooler say 19 degrees compared to summer months when my temp flucs between 22-26

This is where we differ I have had the large number of males in summer with the higher temperature