Determination of transducer types and frequencies in gonadal ultrasound of striped catfish Pangasianodon hypophthalmus (Sauvage, 1878)

Ultrasound images can be utilized as a non-invasive method for the sex determination of striped catfish Pangasianodon hypophthalmus (Sauvage, 1878) for future breeding in a reproductive program. Striped catfish of various sizes were examined for gonads using an ultrasound machine. The results showed that for striped catfish less than 3 kg, a micro convex probe (5.0 MHz frequency), convex probe (3.5 - 5.0 MHz frequency), and linear probe (5.0 MHz frequency) could be used to examine gonads in ventral fish position. In a comprehensive examination of both ovaries, convex and micro convex probes gave high-potential ultrasound images but could not identify their testis. In the case of sizeable striped catfish over 3 kg, using the convex probe (3.5 - 5.0 MHz frequency) and micro convex (5.0 MHz frequency) resulted in the best ultrasound images of ovaries. When the fish were at the stage of sexual maturity, it was possible to distinguish between the ovaries and the testis on ultrasound images.