When is the gender (whether it's a male or a female) determined in salmon? I believe their gender (whether they are a male or female) is determined at birth but, some people believe their gender is some how mysteriously determined while they are at sea. I've searched the www. & can't find the answer. Do you know?

PS: I can't believe nature would allow environmental conditions at sea determine the gender because if the fuish were all in the same environment, wouldn't they all become males (or females) thus ending the species??

I think it may be shortly after the eggs are fertilized - based on water temp. I think this is how the hatcheries control this. But I may be thinking of something else...

I believe that gender is determined genetically, that is, at fertilization.

Temperature is used in hatcheries to create sterile fish, such as triploids, so that they are unable to spawn if they find their way into the wild (or are released). I think they hit the eggs with some very high temps at just the right time for a very short time and this causes an extra set of chromosomes, hence "triploids" rather than "diploids". Since the fish are now unable to spawn, they don't waste any energy creating gametes and use it all to grow, grow, grow.

I think that's the way it is, at least...

Fish on...

Todd.