Frequency of lesions in the caudal fin of Poecilia vivipara in response to predation by exotic species in an urban lagoon

Abstract

This study evaluated the occurrence of caudal fin injuries in Poecilia vivipara caused by Serrasalmus maculatus bites, in relation to standard length (SL) and condition factor, in Lagoa da Saudade (Santos, São Paulo). 90 individuals of P. vivipara were collected between May and July 2025, measured (SL), and classified by a caudal fin integrity index. Most had more than 50% of their fin damaged, and only 12.22% had a fully intact fin. Uninjured individuals were significantly smaller than injured ones, but there was no difference in condition factor. The data indicate that larger P. vivipara are more prone to mutilation by S. maculatus, but that prey choice or vulnerability is not dependent on its current body condition.