Absence of the invasive golden mussel in a reservoir near Curitiba, Brazil: A possible case of invasion failure

Although most cases of non-native species introductions do not result in the final phases of the invasion process or in negative impacts, there are few reports of failure through their different stages, especially for unintentional introductions. However, unsuccessful invasion cases may help understand which factors are predominant during the invasion process. The golden mussel, Limnoperna fortunei, is an invasive species in South America. Since its first record in Río de la Plata watershed, it has spread and caused several ecological and economic impacts in different hydrographic basins. Based on larval sampling through conventional and molecular techniques and visual census by scuba diving, we report the absence of this invasive species after its occurrence recorded in 2003, at the Piraquara I reservoir, Upper Iguaçu River basin, Brazil. It is the only potential record of juvenile individuals of this species in a reservoir environment without their population establishment and spreading. Understanding the causes of failures in the invasion process may be crucial to avoid their negative impacts. In this context, the accuracy of non-native species records in new environments is fundamental; recording invasion failure of non-native species may be as important as reporting new occurrences.