Are gobiid fish more susceptible to predation if parasitized byEustrongylides excisus? An answer from robbed snakes

Abstract

AbstractAspects of the predator–prey relationship between dice snake,Natrix tessellataand gobiid fish infected withEustrongylides excisuswere studied in Lake Sinoe, Romania. A population of snakes residing here shows a high prevalence of subcutaneous larvae of this nematode. The hypothesis of the altered motility in infected fish leading to increased depredation by snakes was tested by comparing gobiids collected from dice snakes with gobiids caught via electrofishing. Out of a total of seven identified gobiid species, three were used for analysis: syrman gobyNeogobius syrman, mushroom gobyNeogobius eurycephalus, and round gobyNeogobius melanostomus. No significant differences in prevalence and intensity ofE.excisusinfection were found between fish caught by snakes and those obtained by electrofishing. However, significantly higher abundance ofE.excisuslarvae in fish caught by snakes was reported. These findings suggest limited influence of the presence ofE.excisuslarvae in studied gobiids regarding their susceptibility to predation by dice snakes.