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.
_________________________


Team Flying Super Ditch Pickle