I will tell you from my own experience, that I will no longer sex another species, the yellow perch, based on the appearance of the urogenital openings. Two springs ago post spawn, I had about 100 yellow perch 8 to 11 inches I got back from two of the high schools that overwinter them indoors for me in systems I set up for them.
Anyway about 20 were textbook as far as female urogenital openings and I planted them in the female only perch pond. The rest were very iffy so they went into a cage.
Fast forward this year and I have YOY yellow perch in the pond. Apparently at least one of those fish was a male.
If I was to give advice to anyone sexing a species that does not show definitive sexual dimorphism, that would be to only sex a fish by the presence of sex products, i.e., milt when the fish is gently squeezed during spawning time, or a definite plumpness due to enlarged ovaries. Using a catheter tube if the fish appears to be a female to extract eggs would be a good idea.
If in doubt keep it out should be your motto if you are striving to have a monosex pond.
Perhaps the accuracy of my sexing was compromised in my pond due to the young age of the perch? (1 +)
Last edited by Cecil Baird1; 07/24/1510:41 PM.
If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.
