Variations of plerocercoid infection rates in fish communities across Spanish mountain lakes

Abstract

Plerocercoid infection rates in fish may result from factors influencing individual and species-specific susceptibility to procercoid infection in copepods. In this paper, we examine the infection rates of fish communities in Spanish mountain lakes by Ligula plerocercoids and explore potential factors that may influence the differences across 9 fish species and 13 lake systems. This study is the first to report the presence of plerocercoids in endemic Bermejuela del Esla (Achondrostoma asturicense), with prevalence rates ranging from 0 to 42.5%. We significantly observed low feeding intensities (gut fullness) and gonadal atrophy in infected A. asturicense compared to non-infected individuals, but zooplankton was absent in the gut contents of A. asturicense. We posit that the absence of fish-eating birds in high-altitude lakes, along with fish abundance and species-specific differences in fish foraging behaviours, likely explains the geographical variations in plerocercoid prevalence across lake-dwelling fish communities.