Ultrasonography, exfoliative cytology, and celiotomy as sex determination methods for Pimelodus maculatus

Abstract

This study explored ultrasonography, exfoliative cytology, and celiotomy as methods for sex determination in Pimelodus maculatus, a species included in fish-stocking programs aimed at conserving and recovering populations affected by hydroelectric power plant activity. Three-year-old fish (n=40), with an average weight of 81.3 ± 16.6 g and average length of 18.9 ± 1.2 cm, were examined in series, according to the degree of invasiveness of these techniques. Ultrasonography showed the ovaries as structures with smooth and defined margins and hypoechoic and homogeneous parenchyma, while the testes were isoechoic to the adjacent structures. Cytology of the urogenital region revealed cellular elements with an accuracy rate of 80 % for females and zero for males. In celiotomy, 100 % accuracy in sex determination was achieved, with 100 % survival after 30 days, indicating rapid recovery. This study provides new insights into the applicability of methodologies for determining the sex of P. maculatus, thereby contributing to the management and conservation of this species.

Keywords

• Neotropical fish
• Pintado-amarelo
• Siluriformes