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??
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Max