Status ofPseudorasbora parvain the Tiber River Basin (Umbria, central Italy) 20 years after its introduction

Abstract

-The aim of this research was to assess the distribution, abundance and growth of the non-native topmouth gudgeon Pseudorasbora parva that was recorded for the first time in the Tiber River Basin (central Italy) in 1994. The competitive interaction of P. parva with four native fish species was also investigated. The study area comprised 92 watercourses of the Umbrian section of the Tiber River Basin. Demographic and environmental data were collected during the period 1990−2014 in 171 sampling sites. The results of this study showed a wide distribution of P. parva in the study area, with records from 23.39% of all sampling sites (40 out of 171). This species inhabits the downstream reaches, where the presence of many non-native species and the poor environmental quality are associated with a decrease in native fish species. A total of 5570 specimens of P. parva were collected and five age classes (0 + to 4 + ) were identified. The equation for the total length-weight relationship of P. parva was W = 0.021T L 2.673±0.015 . For the chub Squalius squalus, the Tiber barbel, Barbus tyberinus, and the roach, Rutilus rubilio, the average values of the relative weight were significantly higher in the sites where P. parva was absent. The results of the present study suggest the need to undertake proper strategies for native biodiversity conservation.Key-words: non-native species / distribution / growth / relative weight / longitudinal gradient Résumé -Le statut de Pseudorasbora parva dans le bassin du fleuve Tibre (Ombrie, Italie centrale) 20 ans après son introduction. L'objectif de cette recherche était d'évaluer la distribution, l'abondance et la croissance de Pseudorasbora parva non-indigène qui a été observé pour la première fois en 1994 dans le bassin du fleuve Tibre. L'interaction compétitive de P. parva avec quatre espèces de poissons indigènes a également été étudiée. La zone d'étude comprend 92 cours d'eau de la région ombrienne du bassin du fleuve Tibre. Les données démographiques et environnementales ont été recueillies au cours de la période 1990−2014 dans 171 sites d'échantillonnage. Les résultats de cette étude ont montré une large distribution de P. parva dans la zone d'étude, avec sa présence dans 23,39% de tous les sites d'échantillonnage (40 sur 171). Cette espèce habite les tronçons aval, où la présence de nombreuses espèces non indigènes et de la faible qualité de l'environnement ont été associées à une diminution des espèces de poissons indigènes. Un total de 5570 spécimens de P. parva ont été recueillis et cinq classes d'âge (0 + à 4 + ) ont été identifiées. L'équation de la relation longueur totale − poids était W = 0.021T L 2.673±0.015 . Pour le chevesne Squalius squalus, le barbeau du Tibre Barbus tyberinus et le gardon Rutilus rubilio les valeurs moyennes du poids relatif (Wr) étaient significativement plus élevées dans les sites où P. parva était absent. Les résultats de la présente étude suggèrent la nécessité d'entreprendre des stratégies appropriées pour la conservation de la biodiv...

Endemic Freshwater Fish Range Shifts Related to Global Climate Changes: A Long-Term Study Provides Some Observational Evidence for the Mediterranean Area

“…Similarly to previous studies [28,45], our CCA demonstrates how the fish species are distributed along the longitudinal gradient of the watercourses and which are the environmental variables that most influence their distribution. As reported for other watersheds in the Mediterranean area [70], also in the Tiber River basin the longitudinal gradient was associated with a progressive decline in water quality, proceeding from upstream to downstream, demonstrated by the decrease of EBI and increased conductivity and concentration of dissolved salts.…”

“…were derived from digital maps (geographic information system (GIS)) provided by the Forest, Economics and Mountain Territory Service of the Umbria Region. In order to evaluate water quality based on the presence of macro-invertebrates, the Extended Biotic Index (EBI) was used [44] (for more details, see [45]). To examine the opportunity for fish species to move upstream, the presence of dams and weirs located in the hydrographic network were detected and their geographical coordinates were derived using a GARMIN global positioning system (GPS) map 62 s with accuracy <10 m. The river fragmentation degree has been codified as the number of weirs with height >80 cm present downstream of each sampling site, up to the main receptor watercourse.…”

The Role of Climate Changes in the Spread of Freshwater Fishes: Implications for Alien Cool and Warm-Water Species in a Mediterranean Basin

“…Previous research carried out on fish communities inhabiting the Tiber river basin (central Italy) have shown that most of alien freshwater fish have been introduced over the last 30 years through restocking activities in favor of recreational fishery [20]; they have been initially released in multiple sites, and subsequently expanded their range using the connections of the hydrographic network [24]. Some of these species, as Barbus barbus (Linnaeus, 1758), Gobio gobio (Linnaeus, 1758), Padogobius bonelli (Bonaparte, 1846) and Pseudorasbora parva (Temminck & Schlegel, 1846), immediately after their introduction occurred in the period between 1993 and 1999, quickly acclimatized and are currently present with many self-sustaining populations [25,26]. Worryingly, the spread of these invasive species has contributed to the local extinction or range shift of some endemic ones.…”

Morphometric features of topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel, 1846) in the Hirfanlı Reservoir, Turkey

“…There are many studies on various features of P. parva at national and international (Erk'akan, 1984, Wildekamp et al, 1997, Cakic et al, 2004, Ekmekçi & Kırankaya, 2006Britton et al, 2007;Boltachev, 2006;Karabanov et al, 2010;Wang et al, 2012;Patimar & Baensaf, 2012;Huo et al, 2012;Tarkan et al, 2014;Kırankaya et al, 2014;Kapusta et al, 2014;Tarkan et al, 2015;İlhan & Sarı 2015;Carosi et al, 2016;Benzer et al, 2016;Bakaç et al, 2017;Benzer 2018;Benzer & Benzer 2019) in the different locations. This paper describes the area where this fish was found and recorded morphometric data of the population in Hirfanlı Reservoir.…”