Prevalence and intensity of black-spot disease in fish community from a subtropical stream (Santa Lucía river basin, Uruguay)

Abstract

Prevalence and intensity of black-spot disease in a fish community from a subtropical stream (Santa Lucriver basin, Uruguay) The objective of the present study was to identify fish species susceptible to black spot disease, the temporal variation in intensity prevalence and abundance of black spot, and its correlation with environmental and host parameters. In order to do so, several sampling campaigns were conducted bimonthly during one year, along the main course of an agricultural watershed. A total of twenty-seven fish species were collected, out of which only two, Astyanax aff. fasciatus (mojarra) and Oligosarcus jenynsii (dientudo) presented black spot disease. In A. aff. fasciatus, 63 % of black spot prevalence was registered and did not show significant seasonal changes during the sampling period, nor did the abundance and intensity. Regarding possible relations between the disease and environmental and host parameters, a higher intensity of black spot infection was observed in the ventral region of the fish and allometric coefficient (WT − LS, relationship) values did not differ significantly between parasitized and non-parasitized fish groups.