Prevalence is positively associated with host tolerance to environmental degradation in riverine fish in north-eastern Spain: example with lernaeids and water molds

Identifying the most vulnerable fish species to disease can aid in the management of wild stocks. Here, the prevalence of widely distributed pathogens (copepod crustacean lernaeids and Oomycetes or water molds) was associated with the tolerance of Spanish endemic and widely distributed native and exotic fish to environmental degradation. Apart from the cyprinid fish Achondrostoma arcasii these infections affected all species. It was observed that the fish species relatively 'tolerant' to physical habitat degradation and water quality exhibited higher prevalence than those 'intolerant'. Prevalence, however, was not influenced by the IUCN endangered or native status of fish species. Although prevalence was low in north-eastem Spain (<9%), it proved to be a pertinent case to discuss the potential of predicting fish vulnerability to disease from its tolerance to poor environmental conditions. This study also identified particular fish species as new lernaeids hosts in Spanish rivers.