Oreochromis niloticus is the most cultivated fish species in Brazil, representing 60.6% of fish production in our country. Tilapia is mainly produced in net cages, however, excavated or natural ponds have also been used. We surveyed parasites in tilapias collected in ponds from a river spring and discuss its ecological implications.
During an inventory of fishes and parasites conducted in 2020/2021, 32 specimens of O. niloticus specimens were collected from a spring river area of Pardo River, Botucatu, São Paulo state, Brazil (23°0’21.21"S, 48°22’31.99"W) and screened for monogenean, crustacean, and myxozoan parasites.
The analyzed tilapias were only infested with monogeneans (Cichlidogyrus halli, C. mbirizei, C. thurstone, C. tilapiae, C. philander, and Scutogyrus longicornis) (Tab. 1, Fig. 1) and copepods (Lamproglena sp., Rhinergasilus piranhus, and Tropocyclops sp.) (Fig. 2).
Many farmers have lakes on their properties and, for several reasons and without proper technical knowledge, try to produce tilapia and end up introducing them and their parasites as alien species. Studies have been demonstrated the negative impact of the introduction of tilapias on the population of native fauna.
Tilapias were infested with six monogenean species. However, these parasites have not been detected in native fishes so far. On the other hand, we found three native crustaceans infesting some tilapias.
We recommend a management plan to control this alien species avoiding the extinction of native species and future parasite-host switch among fishes, mainly in river springs.