Does water temp. affect sex?
- Thread starter Porcelina
- Start date
I know a guy that works in a salmon hatchery and he told me they chill the eggs to produce all female stock when needed...Left normal you will get a 50/50 you chill them and you get 99% females (Sound like a blood parrot to you guys also?)....Again he deals with salmon so it could just be them, but he says it should work the same with all fish. I know my statement is profound , but through my own research I find it to be true also....
That's really interesting, but I wonder if perhaps livebearers are different from egg layers. I know that most reptiles like snakes and alligators can produce all males or females depending upon the temp. of their nests. It only makes sense that egg laying fish would have similar outcomes. However, livebearers do not lay eggs and my tanks are always kept at 80-82 F which is not very cold at all.
Males may be slow to develop around a mature male. On top of that, the majority of livebearer fry are female, but the ratio isn't anywhere near 1:1.
Plecosterone
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Interesting find:
Skewed sex ratios are common among several species of Poeciliopsis, a viviparous fish from northwestern Mexico. Since previous, unrelated studies from this laboratory (Angus and Schultz, 1983) suggested that deviation from a 1:1 sex ratio might be influenced by temperature, two inbred strains of P. lucida were tested for temperature-dependent sex determination by comparing sex ratios of offspring from pregnant females held at different water temperatures. Different sex ratios were produced by the two strains at the same temperature: one strain produced almost all-male offspring at 30$^\circ$C and female-biased sex ratios at 24$^\circ$C, while the other strain produced a 1:1 sex ratio at both temperatures. At intermediate temperatures, the labile strain produced sequentially fewer males with decreasing temperatures. The other strain produced a consistent sex ratio regardless of temperature. Poeciliopsis lucida apparently has a genetic polymorphism for temperature-influenced sex determination. An hypothesis is offered for the evolutionary origin of environmental sex determination.
Found here
Skewed sex ratios are common among several species of Poeciliopsis, a viviparous fish from northwestern Mexico. Since previous, unrelated studies from this laboratory (Angus and Schultz, 1983) suggested that deviation from a 1:1 sex ratio might be influenced by temperature, two inbred strains of P. lucida were tested for temperature-dependent sex determination by comparing sex ratios of offspring from pregnant females held at different water temperatures. Different sex ratios were produced by the two strains at the same temperature: one strain produced almost all-male offspring at 30$^\circ$C and female-biased sex ratios at 24$^\circ$C, while the other strain produced a 1:1 sex ratio at both temperatures. At intermediate temperatures, the labile strain produced sequentially fewer males with decreasing temperatures. The other strain produced a consistent sex ratio regardless of temperature. Poeciliopsis lucida apparently has a genetic polymorphism for temperature-influenced sex determination. An hypothesis is offered for the evolutionary origin of environmental sex determination.
Found here
How long will it take for young males to develop around a mature male? My youngest fry are 3 months old and only one of them is male. The other fry range from 4 to 8 months old and all of them appear to be female.
it really depends on the species of fish...with mollies, it will be when you can definitley tell their gender.