Skunked, here are few more to dig your teeth into.

A good one.

This is good too.

Yet something else I think you would enjoy.

Website condensing Swingle's principles

Just in case you are really interested in doing single sex catfish. The males grow faster with lower filet % yield typically and could burrow to make nests. The females grow slower but may have other benefits like they are not as aggressive and don't dig holes.

Quote
Determining Sex
Secondary sex characteristics are often used in sex determination with mature adults. These characteristics include body shape and coloration. Males are usually larger and have broader heads than females. As spawning season approaches, males become leaner, develop even larger, muscular heads, and turn a dark bluish to black color.
Females' heads are narrower than their bodies when viewed from the top. As spawning season approaches, they develop soft, swollen bellies. Their color remains gray to olive.

Genital Examination

Turn the fish belly up. Two or three openings are present. The opening nearest the head is the anus. The one nearest the tail is the genital opening.

Males: The genital opening is at the end of a fleshy, nipple-like structure. It is called the genital papilla. It becomes more visible, swollen and rigid as spawning season approaches. Selection of robust males is based on those with a thick well muscled body and head, dark coloration especially on the usually white underside and with a well-defined papilla. Males will have only two openings.

Females: The vent or genital area is oval and flat. There are two obvious openings separated by a third one covered by a small flap of skin. A slit or groove is located at the head end of the genital area. The urinary opening is located at the tail end of the genital area. The genital area becomes swollen and reddish in color as spawning time approaches. The swollen vent characteristic only indicates spawning season is approaching and is not a trait for selection. The soft swollen abdomen and general body shape are the best characters for selecting brood females.

With immature fish or fish not yet mature or in spawning condition, the following method will assist in determining sex of selected. Two people are required to rapid handling and determination of sex. Fish are firmly held in a belly-up position. Grasp the head with one hand and firmly clasp the tail with the other. With the fish's head just below your chest and the tail away from your body, gently arch the fish's belly upward. This causes the male papilla or the female genital slit to become distended and more visible. On fish with less pronounced genital development have your assistant slide a probe (or blunt pencil) over the genital area toward the tail. If the probe catches in the genital opening, the fish is female.

Last edited by jpsdad; 10/28/21 05:03 PM.
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