DIVERSIDAD DE PARÁSITOS DE CNESTERODON DECEMMACULATUS EN UN ARROYO DE LA REGION PAMPEANA SOMETIDO A LA URBANIZACION

YASMIN CROCI; ROSARIO IGLESIAS; YAMILA RESHAID; MACARENA DE MARTINO; MARTIN ACOSTA ALBARRACIN; JORGE BARNECHE; SERGIO R. MARTORELLI; MARTIN M. MONTES

Congreso; XI Congreso Internacional de Parasitología Neotropical; 2023

The Rodriguez stream (34°52'15.3" S; 58°01'47.0" W) is located in the province of Buenos Aires, Argentina, has a length of about 23 km and a surface area of 54 km2 and is included in the Pampean region. It originates in semirural areas at the north-west of La Plata City, runs across urban areas in its middle course and across rural areas in its lower course before discharging into the Río de La Plata Estuary through a channelized upper section. With the Google Earth Engine platform, we delimited the study area with a line and a 500 meter radius buffer was made. Scenes from Sentinel 2, 10 meter spatial resolution with no cloud cover present, were leaked. With these images, the NDVI was calculated in order to characterize the study area. Cnesterodon decemmaculatus was the only fish species present in the lower section of the stream during the study period. Fish were examined for helminths under a binocular stereo-microscope. Parasites were observed in vivo, counted, killed in hot water and preserved in 90% alcohol or fixed and preserved in 10% formalin. The area was classified into urban coverage (29.8%), low vegetation (48.28%), high vegetation (20.51%) and water (1.38%). All individuals of C. decemmaculatus examined harbored eight parasite species represented by: larvae of Echinostomatidae (Stephanoprora sp.) in gill filaments, larvae of Heterophyidae in gill filaments (Ascocotyle sp.1), heart arterial bulb (Ascocotyle sp.2), muscles (Ascocotyle sp.3) and mesenteries (Pygidiopsis sp.), larvae of Diplostomidae (Posthodiplostomum sp.) in body cavity and mesenteries, adults of Haploporidae (Saccocoelioides kirchneri Martorelli et al. 2022) and adults of Neoechinorhynchidae (Wolffhugelia matercula Maňé-Garzón and Dei-Cas 1974). Cnesterodon decemmaculatus was the only fish present from the lower section of the Rodriguez stream during the whole study period probably because it is resistant to environmental pollution. The fact that about 80% of the parasites were larvae indicates the high suitability of C. decemmaculatus as intermediate host. On this basis, future studies carried out along the stream during the year will contribute to generating a more complete database of parasite dynamics and environmental parameters for future comparisons.