Intraguild predation as a potential explanation for the population decline of the threatened native fish, the European mudminnow (Umbra krameri Walbaum, 1792) by the invasive Amur sleeper (Perccottus glenii Dybowski, 1877)

specimens tended to feed on a relatively higher proportion of fish. Our results suggested that temporal resolution of stomach content analyses may largely determine inferences on the importance of predation on juvenile mudminnow. Overall, we found that intraguild predation could contribute to the decline of European mudminnow populations, which underscores the importance of effective control measures to prevent the further spread of the invasive Amur sleeper.