Age and growth of Pseudoplatystoma corruscans (Siluriformes: Pimelodidae) at the confluence of the Parana and Paraguay rivers

The age and growth of Pseudoplatystoma corruscans, is analyzed on specimens landed in Puerto Antequera, Province of Chaco, Argentina. The study is based on length frequency distribution of 1192 individuals and growth marks of 293 pectoral spines. Previously to age assignation based on spines readings, we performed analyses that ruled out age-associated resorption of rings and corroborated the annual periodicity of mark formation. The average sizes of the radius of each ring were obtained, and the total length of fish were back-calculated to the time of the ring formation, by the regression model fitted between the total radius of the spines to the respective sizes of each fish. Such data showed a good fitting to growth models of von Bertalanffy, Gompertz and logistic for both sexes separately. Results indicate that the study of the species growth must be carried out for each sex separately and that the fishing regulations must consider this characteristic of the species since the current management guidelines could be promoting differential capture by sexes.

Automated summary

The age and growth of Pseudoplatystoma corruscans were analyzed based on length frequency distribution and growth marks of pectoral spines. Results showed that different growth models are suitable for males and females of the species, suggesting the need for separate studies for each sex and consideration of this characteristic in fishing regulations.