Length-weight relationship and condition factor for Prochilodus lineatus, an important commercial fish, in contrasting water-quality environments of the middle Tiete River basin, Southeast Brazil

Author(s)

Urbanski, Bruna Q. ; Brambilla, Eduardo M. ; Nogueira, Marcos G.

• Document type: Journal article
• Source: Biota Neotropica; v. 23, n. 2, p. 5-pg., 2023-01-01.

Abstract

This work was carried out in order to provide the length-weight relationship (LWR) and the allometric condition factor (Ka), as well as its correlation with limnological variables, for Prochilodus lineatus from the middle Tiete River basin. Fish were collected using gill nets in two rivers with contrasting environmental conditions, totaling 46 specimens in the highly polluted Tiete River, and 37 in the Peixe River, a relatively well-conserved tributary. Environmental measures were obtained concomitantly to the fish capture. The results showed an isometric growth (b = 3.00) for the fish from Tiete River and a positive allometric growth (b = 3.23) for the fish from Peixe River. The mean value of Ka was unexpectedly higher for the main river (Ka = 2.63) when compared to its tributary (Ka = 2.42), being statistically different from each other. This can be explained by the much higher availability of organic sediments in the main river, resulting from a long-term eutrophication process. Nevertheless, the positive and statistically significant correlations with dissolved oxygen, for both rivers, as well as significant negative correlations with electric conductivity, nitrogen and chlorophyll a for Tiete River, indicate the negative effects of the water quality deterioration on the fish condition factor. The work contributes to the expansion of knowledge about P. lineatus, the most important commercial fish of the middle Tiete River basin, which is severely impacted by unsustainable human actions. (AU)

• FAPESP's process: 19/00177-4 - Chemical barrier for the dispersion of ichthyofauna: an analysis of the Tietê River and its tributaries
• Grantee: Bruna Quirici Urbanski
• Support Opportunities: Scholarships in Brazil - Master