ECOLOGICAL ASPECTS OF THE INVADING TREMATODE CENTROCESTUS FORMOSANUS (NISHIGORI, 1924) (TREMATODA: HETEROPHYIDAE) IN THE NILE TILAPIA OREOCHROMIS NILOTICUS (LINNAEUS, 1758) (PERCIFORMES, CICHLIDAE), IN THE WETLAND LOS PANTANOS DE VILLA, LIMA, PERU

Abstract

Nile Tilapia Oreochromis niloticus (Linnaeus, 1758) is an endemic freshwater fish native to Africa. Oreochromis is the most critical genus in aquaculture because it has the highest growth rates, easy reproduction, and management. The present work's objective was to evaluate some ecological aspects of the invading metacercaria Centrocestus formosanus (Nishigori, 1924) (Trematoda: Heterophyidae) in O. niloticus in the wetlands of Pantanos de Villa, Lima, Peru. Twenty specimens of O. niloticus collected in the Genesis, and Marvilla lagoons in Pantanos de Villa's wetlands were inspected parasitologically during February and October of 2012. The fish had an average weight and length of 221.3 g ± 111.4 and 19.6 cm ± 4.24 cm, respectively. The invasive ectoparasite metacercariae were cataloged and evaluated using standard parasitological protocols. During the entire sampling, a total of 130 C. formosanus trematodes was collected, with an average abundance of sixty percent of the Nile Tilapias were parasitized by C. formosanus. The relative condition factor (k_n), an indicator of host fish health, was not influenced by the presence of C. formosanus. Centrocestus formosanus has been recorded in birds and mammals, including humans producing heterophils, a worldwide emerging disease in humans transmitted by raw fish consumption. Centrocestus formosanus in Peru represents a potential zoonotic impact on public health. The presence of the dynozoan ectoparasite Amyloodinium ocellatum Brown & Hovasse, 1946, can cause pathological alterations in marine fish and saline environments found in gills in a single host.