Origin and history of Phoxinus (Cyprinidae) introductions in the Douro basin (Iberian Peninsula): an update inferred from genetic data

The number of non-native freshwater fishes in the Iberian Peninsula has been greatly increasing. In this study, individuals of the genus Phoxinus were detected in 18 out of 138 stream sites sampled across the Douro Basin in 2017 and 2018. A total of 26 individuals were barcoded using partial cytochrome c oxidase subunit I (COI) and cytochrome b (cytb) genes for species identification and determination of geographical origin. Molecular data provided the first record of a second Phoxinus species in western Douro (Portugal, Iberian Peninsula), with haplotypes closely matching those found in the Charente River (southern France). This species is suspected to be a recent introduction associated with the use of minnows as live bait by freshwater anglers, which was facilitated by human movements between France and Portugal. Individuals from watercourses in eastern Douro (Spain) were genetically assigned to Phoxinus bigerri, an introduced species previously known for that region, which confirms reports of introduction events from Ebro to Douro Basin probably also related to freshwater angling and facilitated by geographic proximity. The potential ecological impacts of this genus in the region are unknown and need further investigation.We acknowledge Fernando Teixeira, Fernando Miranda, Mario Ferreira, Sara Carona, Jose Pedro RamiAo and Francisco Carvalho for the valuable assistance during fieldwork. We specially thank Maria Filomena MagalhAes for previous fruitful discussions and logistic support. We are grateful to Matthias F. Geiger and Andrea Corral Lou for facilitating genetic data and coordinates of sampling sites. Finally, we appreciate the comments of the three anonymous reviewers that improved the quality of the manuscript. AFF and AGR were supported by the project FRESHING founded by the Portuguese Foundation for Science and Technology (FCT) and COMPETE (PTDC/AAGMAA/2261/2014 - POCI-01-0145-FEDER-356016824). FMSM was supported by the FCT PhD grant SFRH/BD/104703/2014. This study was conducted as part of the projects FRESHING and FRESHCO. The latter is also supported by FCT and COMPETE (PTDC/AGR-FOR/1627/2014 - 04/SAICT/2015) and UID/AGR/04033/2019. Logistic support was also facilitated by the ENVMETAGEN - Capacity Building at InBIO for Research and Innovation Using Environmental Metagenomics project at CIBIO laboratories (668981; EUH2020-WIDESPREAD-2014-2)

The Apparently Relentless Spread of the Major Decapod Alien Species in the Mediterranean Basin and European Inland Waters

Among the many alien crustacean species so far recorded in the Mediterranean basin are numerous decapods\u2014crayfish, crabs and prawns\u2014that have in common the reputation of being both aggressive and adaptable to various environments. Their entrance to the Mediterranean basin has often been fostered by human actions, such as the transfer of new species for commercial purposes or accidentally, as bycatch or because they were present in discarded ships\u2019 ballast water. Marine alien species enter the Mediterranean basin from two main directions: from the Atlantic and beyond, and from the Indian Ocean via the Suez Canal. For freshwaters, the extensive European canal network is an important aid to migration, but human discards are also significant. Protection of native fauna and ecosystems is at best partial. Freshwater ecosystems particularly at risk include lagoons, river estuaries, ponds and marshes, while comparable marine systems are shallow muddy coastal regions, rocky reefs, estuaries/bays and salt marshes. Local communities, principally anglers and people working with aquatic resources, usually are curious at the appearance of a new species and the possibility of establishing a new business is often the first thought. However, freshwater decapod alien species cause major damage to agriculture production, infrastructures, riverbanks, irrigation systems and fish production, leading to consistent economic losses. In particular, they are known to be injurious to plant production, causing increasing losses to agriculture, consuming young seedlings and seeds and causing substantial water losses from field areas. Less information is available for seawater species to date, but their increasing number and growing size of populations requires the attention of the scientific community to evaluate and predict their influence on the marine environment and/or on local fish and bivalve production. Both freshwater and marine alien decapods thus represent a serious threat to native European species and have a negative impact on species richness and habitats. The economic losses caused by these species require reliable and cost-effective options for managing their abundance and if possible for their eradication

A horizon scan exercise for aquatic invasive alien species in Iberian inland waters

As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for potential application at any geographical or administrative scale, including the continental one