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Updating information on the distribution of recently introduced and other poorly known non-natives is essential to prevent and control their spread and better address biological invasions. Here, we combine scientific and citizen science data to update the distribution of five recently arrived (i.e., < 25 years), non-native fish species (Alburnus alburnus, Ameiurus melas, Rutilus rutilus, Sander lucioperca and Silurus glanis) and one rare, longer established (i.e., > 50 years), non-native (Esox lucius) in Portugal. These species have been increasingly targeted by recreational fishermen, thus likely expanding their distribution. Specifically, we obtained distribution maps for each species, based on data gathered through a comprehensive search for records in 1) scientific literature, 2) unpublished reports of research projects, and 3) citizen science databases. We gathered 443 valid records, of which 64% were from citizen science data, mainly provided by recreational fishermen. Data highlighted that all species have expanded their distribution in the last 20 years, with high numbers of new records for A. alburnus, S. lucioperca and S. glanis, mostly located in the Tagus, Guadiana and Douro river basins. Changes in species distributions reflected dispersal within invaded basins and colonisation of previously unoccupied drainages. Integrating citizen science with scientific data provides an effective framework to understand non-native species introduction and spread, stressing the need for increasingly encourage and engage recreational fishermen in information sharing. [ABSTRACT FROM AUTHOR]

The zebra mussel, Dreissena polymorpha, has strong economic and environmental effects within a wide range of habitats, including reservoirs, and there is a need to monitor in advance of an arrival so that an elimination might be possible. We report the establishment of the zebra mussel in the Alfundão Reservoir, a small reservoir in south Portugal, 190 km away from the closest known population in Spain. The area has been monitored using suspended ropes since 2016, and during October 2019, mussels of 5-43.8 mm shell length were recorded for the first time in the Alfundão reservoir. The shallow lined reservoir was then chlorinated and drained. To date, this treatment appears to have been successful in eliminating this population. It is unknown how this mussel arrived, since the reservoir area has a surrounding exclusion zone. [ABSTRACT FROM AUTHOR]