Aquatic Invasions (2010) Volume 5, Issue 3: 291-296 doi: 10.3391/ai.2010.5.3.06 Open Access © 2010 The Author(s). Journal compilation © 2010 REABIC Proceedings of the Symposium on non-native freshwater species introduction in the Iberian Peninsula 12-13 November 2009, Pamplona, Spain Aquatic Invasions Records Additional records of non-native freshwater fishes for the Ebro River basin (Northeast Spain) Rafael Miranda1*, Pedro M. Leunda2, Javier Oscoz1, Antonio Vilches1, Ibon Tobes1, Javier Madoz3 3 and Jaime Martínez-Lage 1Department of Zoology and Ecology, University of Navarra, PO Box 177, E-31080, Pamplona, Navarra, Spain 2Gestión Ambiental Viveros y Repoblaciones de Navarra S.A., C/ Padre Adoain 219 Bajo, 31015 Pamplona/Iruña, Navarra, Spain 3Flumen estudios y proyectos ambientales, C/ Errotazar 23, bajo, 31014 Pamplona, Navarra, Spain E-mail: [email protected](RM), [email protected] (PML), [email protected] (JO), [email protected] (AV), [email protected] (IT), [email protected] (JM), [email protected] (JML) *Corresponding author Received: 10 February 2010 / Accepted: 7 July 2010 / Published online: 5 August 2010 Abstract This paper extends the knowledge of the geographical distribution of non-native freshwater fishes in the Ebro River basin (Spain). More than two hundred surveys were carried out since 2000, and thirteen non-native fish species were collected on fifty- eight occasions. The spread of most of the recorded non-native species seems to be a consequence of illegal introductions related to sport fishing activities and the subsequent natural dispersal. Their presence could impact natural populations of Iberian native –mostly endemic– freshwater fish species, through direct predation and competition for niche and/or trophic resources. Key words: distribution, fish introductions, range expansion, exotic species, Iberian Peninsula Introduction Gollasch 2006). Within the European continent, Mediterranean areas have the highest Invasive species constitute a major threat to biodiversity but also the highest number of biodiversity and ecosystem integrity and cause threatened species (Medail and Quezel 1999; substantial economic damage (Allan and Flecker Smith and Darwall 2006). Many ecosystems in 1993; Vitousek et al. 1997; Kolar and Lodge these European Mediterranean areas are also 2001). Freshwaters are considered one of the especially susceptible to invasions by introduced most severely degraded ecosystems in species (Clavero et al. 2004). industrialised countries (Oberdorff et al. 2002) Spain is the European Mediterranean country and have been the recipient of many invasions, with the peak value of species diversity and, in particular by fish species (see Copp et al. similarly, has the highest number of threatened 2005; García-Berthou et al. 2005 for review). species according to the International Union for The success of non-native fish has been widely Conservation of Nature Red List of Threatened studied and attributed to several factors species (IUCN 2010). Among the 1,136 native including specific life history traits (Olden et al. species (71 freshwater fish species) catalogued 2006), phylogeny (Alcaraz et al. 2005) and by the IUCN Red List in Spain, 120 species (14 environmental characteristics including abiotic freshwater fish species) are considered factors or human use (Moyle and Light 1996; endangered, critically endangered or extinct, Alcaraz et al. 2005). representing more than 10% (18% of freshwater Impacts on native aquatic fauna are fish species) of the registered biodiversity for considerable and a cause of concern especially in this organisation (IUCN 2010). those places that have suffered constant Knowledge regarding impact mechanisms and introductions along the course of history, such as risk evaluations of non-native species is, without in developed European countries (Panov and doubt, one of the pertinent issues and a key issue 291 R. Miranda et al. in the conservation of the native fauna (Leunda Scardinius erythrophthalmus (Linnaeus, 1758)); 2010). The aim of this paper is to document two centrarchids (Lepomis gibbosus (Linnaeus, additional records of non-native freshwater 1758) and Micropterus salmoides (Lacepède, fishes in the River Ebro basin, north-eastern 1802)); one esocid (Esox lucius Linnaeus, 1758); Spain, obtained from different monitoring one ictalurid (Ameiurus melas (Rafinesque, studies carried out by the authors during the last 1820)); one percid (Sander lucioperca decade. (Linnaeus, 1758)); one poecilid (Gambusia holbrooki (Girard, 1859)); one silurid (Silurus Methods glanis Linnaeus, 1758) and one salmonid (Oncho-rhynchus mykiss (Walbaum, 1792)). The Ebro River is the largest river in Spain, Records of Gambusia holbrooki already draining an area of 86,100 km2 in the north- published by the authors (Oscoz et al. 2008) will eastern Iberian Peninsula (Figure 1). From the not be considered in this contribution, although year 2000 until 2009, 238 surveys were carried new recent records have been included. This out in this basin for several technical reports and species is considered by Eschmeyer (2010) to be research projects. a synonym of Gambusia affinis (Baird and Most surveys were undertaken by electro- Girard, 1853), although Kottelat and Freyhof fishing using backpack units (300-600 V, 0.2-2 (2007) consider it a different species. A) (CEN EN 14011:2003). Different sampling All the species collected have been previously designs were carried out (i.e. three-run depletion reported in the Ebro River basin, and some between two stop-nets, qualitative surveys, semi- species have been previously cited in some of the quantitative surveys) depending on the original places recorded in this work (e.g. Doadrio 2001). purpose of the survey. Surveys in reservoirs were Specifically, the bleak Alburnus alburnus has carried out with multimesh gillnets (CEN EN spread to almost the whole Iberian Peninsula and 14757:2005). Finally, specimens of non-native new records in the Ebro River basin have been fishes were captured in some monitoring surveys reported recently (Vinyoles et al. 2007). In this of biological water quality assessment by macro- study, additional new records are reported for the invertebrate hand-netting, and we were included basin. In particular, middle stretches of the Arga in this study. and Gállego Rivers (sites 21 to 25 and 35 to 37 The caught fish were anaesthetized with 2- in Figure 1 and Annex 1) show the fast spread of phenoxyethanol before being measured to the the bleak in tributary rivers of the basin. nearest 1 mm, and weighted, when possible, to The pumpkinseed Lepomis gibbosus is the nearest 0.01 g. Some of caught specimens considered an invasive species throughout the were stored immediately on ice but not frozen Iberian Peninsula (Gutierrez-Estrada et al. 2000; and transported to the laboratory where the Doadrio 2001; Hermoso et al. 2008), but there specimens were fixed in 4% formaldehyde are few records in the north of Spain (Oliva- solution for 48 h and afterwards preserved in Paterna et al. 2005). In fact, the pumpkinseed has 70% ethanol solution in order to be catalogued in only been reported in the Mequinenza Reservoir the Museum of Zoology, University of Navarra in Doadrio (2001) and from few other sites in the (MZNA) collection (Salinas and Ariño 2000). upper Ebro basin (Zaldivar 2006). In this study Taxonomic review of scientific names and the the pumpkinseed was collected in this Reservoir common names were validated according to the (sites 15 and 16), two sites close to this William N. Eschmeyer’s Catalogue of Fishes Reservoir (sites 52 and 55) and also in additional (Eschmeyer 2010) and Kottelat and Freyhof new localities in the upper Ebro basin (sites 1 (2007). and 2). Regarding zander Sander lucioperca, this is the first published record in the Alcanadre River Results and discussion (Site 41), the Segre River (Site 58), or in the lower Ebro and Cinca River (Sites 15 and 52). Thirteen non-native fishes were collected in 58 This species has been recently cited in other of the 238 surveys carried out in 146 places Iberian locations (Perez-Bote et al. 2004, Perez- (Annex 1, Figure 1): five cyprinids (Alburnus Bote and Roso-Romero 2009). The high pisci- alburnus (Linnaeus, 1758), Carassius auratus vorous specialization of the zander could lead to (Linnaeus, 1758), Cyprinus carpio Linnaeus, a decline in stock of local endangered species 1758, Rutilus rutilus (Linnaeus, 1758) and (Doadrio 2001). It has been previously reported 292 Non-native fishes records for the Ebro basin Figure 1. Location of the sampled reaches without non-native (○) and with non-native (●) freshwater fishes the Ebro River basin. in the literature that the zander has depleted the survival and/or genetic integrity of the native stocks of native fishes in some areas where it has Iberian species (Doadrio 2001). Along with the been introduced for angling (e.g. Innal and introduction of exotic invasive fish species, Erk’akan 2006). habitat degradation – i.e. via dam and weir Finally, new records of the European catfish construction, water extraction, river channeli- Silurus glanis should be commented upon. This zation, flow regime alteration, gravel extraction species has been cited in the Mequinenza – and water pollution is the leading threat to the Reservoir (Site 15, Doadrio 2001) and more survival of the native – mostly endemic – Iberian recently in other Iberian rivers (Carol et al. 2003; freshwater fishes. Benejam et al. 2007). In this study European Although some of the non-native fishes catfish is reported in the Cinca River (Sites 43, mentioned above were originally legally 44 and 52), upstream of the Mequinenza introduced for experimental or sport-fishing Reservoir, and in the upper Ebro River (Sites 5 purposes in under-controlled populations, the to 7 and 11, Zaldivar 2006) more than 200 km subsequent spread is mostly due to unauthorized northwest from this reservoir. It is supposed that and uncontrolled introductions by sport the European catfish is spreading and may be fishermen. Little efforts are being made in Spain present along this 200-km Ebro River stretch.