AUTHOR’S PAGE PROOFS: NOT FOR CIRCULATION CSIRO PUBLISHING Marine and Freshwater Research, 2018, 69, 1–7 Short Communication https://doi.org/10.1071/MF17092 Inter-population variability in growth and reproduction of invasive bleak Alburnus alburnus (Linnaeus, 1758) across the Iberian Peninsula D. LatorreA, G. Maso´ A,J, A. HinckleyB, D. Verdiell-CubedoA, A. S. TarkanC,K, A. Vila-GispertA, G. H. CoppD, J. CucheroussetE, E. da SilvaF, C. Ferna´ndez-DelgadoG, E. Garcı´a-BerthouA, R. MirandaH, F. J. Oliva-PaternaI, A. Ruiz-NavarroI, J. M. SerranoB and D. AlmeidaA,L,M Y AGRECO, Institute of Aquatic Ecology, University of Girona, C/ M. Aure`lia Capmany 69, E-17003 Girona, Spain. BDepartment of Ecology, Complutense University of Madrid, C/ Jose´ Antonio Novais 12, E-28040 Madrid, Spain. CFaculty of Fisheries, Mug˘la Sıtkı Koc¸man University, TR-48000 Mentese, Mug˘la, Turkey. DSalmon & Freshwater Team, Cefas, Pakefield Road, Lowestoft, Suffolk, NR33 OHT, UK. ECNRS, Universite´ Toulouse III Paul Sabatier, ENFA, UMR 5174 EDB (Laboratoire E´volution & Diversite´ Biologique), 118 Rue Narbonne, F-31062 Toulouse, France. FDepartment of Anatomy, Cell Biology & Zoology, University of Extremadura, Avenida De Elvas, s/n, E-06006 Badajoz, Spain. GDepartment of Zoology, University of Co´rdoba, Campus de Rabanales, Edificio Charles Darwin, E-14014 Co´rdoba, Spain. HDepartment of Environmental Biology, School of Sciences, University of Navarra, C/ Irunlarrea 1, E-31080 Pamplona, Spain. IDepartment of Zoology and Physical Anthropology, University of Murcia, Avenida Teniente Flomesta 5, E-30100 Murcia, Spain. AQ1 JDepartment of Biodiversity and Ecological Restoration, Instituto Pirenaico de Ecologı´a (IPE-CSIC), Avenida Nuestra Sen˜ora de la Victoria 16, E-22700 Jaca, Spain. KDepartment of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental AQ2 Protection, 12/16 Banacha Str., PL-90-237, University of Ło´dz´, Poland. LDepartamento de Ciencias Me´dicas Ba´sicas, Facultad de Medicina, Universidad San Pablo-CEU, CEU Universities, Campus de Monteprı´ncipe, E-28925 Alcorco´n, Madrid, Spain. MCorresponding author. Email: [email protected] Abstract. The native European freshwater cyprinid fish, common bleak Alburnus alburnus (Linnaeus, 1758), is an invasive non-native fish in the Iberian Peninsula, where it threatens the valuable endemic fish fauna. Despite the bleak’s invasive status, there is a dearth of studies on the biological traits of non-native populations in Europe’s Mediterranean region, and the presentROOF study aimed to compare bleak growth and reproductive ONL traits across the principal rivers of Iberia 5 with those from a native ‘reference’ bleak population in France. Non-native bleak from the River Tagus had the highest back-calculated total lengths (TLs), growth rate and body condition, but the lowest reproductive investment and smallest egg size of all studied populations. Whereas, these latter two traits were the highest in the River Ebro, where fecundity was the lowest for all Iberian rivers. The youngest age and the smallest TL at maturity were observed in the River Ebro. The River SeguraP had the lowest back-calculated TLs and growth rate, the highest fecundity and proportion of females, and the 10 oldest age at maturity. Population traits of bleak in the River Saoˆne (the native ‘reference’ population) were generally different from those in Iberian rivers, except for the River Ebro. This wide inter-population variability contributes to the species’ successful establishment in novel habitats. Additional keywords: back-calculation, body condition, freshwater fish, non-native species, sex ratio. Received 6 April 2017, accepted 5 December 2017, published online xx xxxxx xxxx Journal compilation Ó CSIRO 2018 www.publish.csiro.au/journals/mfr 2 Marine and Freshwater Research D. Latorre et al. Introduction as well as with regard to a native bleak population of the River Invasive fishes can be major drivers of biodiversity loss in Saoˆne (eastern France), which was used as the ‘reference’ freshwater ecosystems at the global scale (Mooney and Hobbs population because France has historically been the ‘donor 2000). The potentially disruptive effects of non-native fishes are region’ for non-native fish introductions to Iberia along the 5 of particular conservation concern in the Iberian Peninsula, so-called ‘Perpignan–Barcelona corridor’ (see Clavero and 5 where endemism in freshwater fishes is high (.50% of native Garcı´a-Berthou 2006). species) and many of the endemic species are seriously threat- ened (Reyjol et al. 2007). Indeed, introduced fishes currently represent .30% of the total fish species and this continues to Materials and methods 10 increase, which renders the Iberian Peninsula a hotspot for fish Each Iberian sampling site was surveyed for two consecutive invasions (Leunda 2010; Almeida et al. 2013). days by different methods (see details below). In particular, The common bleak Alburnus alburnus (Linnaeus, 1758) is sampling dates were on 25–28 May for Ebro (two sites), 28–31 10 native to most of Europe, from the Pyrenees Mountains to the May for Tagus (two sites), 29 May–1 June for GuadianaY (two Ural Mountains, and including the south-eastern part of Great sites), 22–25 May for Segura (two sites) and 7–10 May for 15 Britain, where this cyprinid species inhabits lakes and medium- Guadalquivir (two sites) and 5–6 June for Saoˆne (one site). The to-large rivers (Keith et al. 2011). In the Iberian Peninsula, following five main Iberian rivers, which are all of typical reservoirs are important locations for the introduction of non- Mediterranean climate, were sampled for bleak along a latitu- 15 native fishes, such as the following trophy species: northern pike dinal gradient (from north to south): Ebro (4184703000N, Esox lucius, largemouth bass Micropterus salmoides, Eurasian 180502400W and 4182603900N, 082802600W), Tagus (3984900700N, 20 perch Perca fluviatilis, European catfish (also known as sheat- 482002500W and 3985801200N, 484201700W), Guadiana fish) Silurus glanis and pikeperch Sander lucioperca. Common (3885905800N, 585105200W and 3885001800N, 681305300W), Segura bleak was first introduced to Spanish reservoirs from southern (3880600500N, 181705000W and 3880405400N, 085303700W) and 20 France during the 1990s as a ‘forage fish’ for the above- Guadalquivir (3783700100N, 583504500Wand3783004600N, mentioned piscivorous fishes (Vinyoles et al. 2007), including 585603800W). These geographic coordinates (given in upstream to 25 the rivers Ebro (in 1992), Guadiana (in 1999), Segura (in 2004) downstream order) correspond to two sampling sites per river. (Andreu-Soler et al. 2004), Tagus (in 2005) and Guadalquivir (in The River Saoˆne reference site (4780201300N, 580605200E), where 2006). Since its introduction, the bleak has displayed a strong the climate is temperate oceanic, was then surveyed in early June. 25 invasive character throughout Iberian fresh waters by natural To provide an appropriate assessment of reproductive traits, and human-assisted (mainly stocking) dispersal, becoming fish were collected from May to June 2012, just before the 30 abundant within Iberian fish assemblages (e.g. Maceda-Veiga spawning period of bleak for each study area (authors, pers. AQ3 et al. 2010). Nevertheless, Iberian fishes are poorly adapted to obs.). Sampling sites (n ¼ 11, two sites per Iberian river plus one sustain the many introductions of non-native fishes, which on the River Saoˆne) were selected to encompass similar envi- 30 usually results in native species being displaced from available ronmental conditions. In particular, land use was mainly for resources. In particular, bleak threatens serval Iberian fishes, agricultural exploitation, sites were located in well-regulated 35 mainly through trophic and interference (i.e. aggression) com- middle reaches of the main channel, and far from the influences petition (Leunda 2010). As an example, direct observations of of main tributaries and towns. Also, sites were separated bleak by snorkelling have clearly shown that bleak can disturb .50 km within each Iberian river. A variety of consistent 35 the foraging behaviour of endemic Ebro nase Parachondrostoma sampling protocols was followed by wading and from boats, miegii (Almeida and Grossman 2012). according to the European legislation (CEN/ISO Standards, EC 40 From a conservation perspective, there is a clear need for Directive 2014/101/UE, European Commission 2014). This information on bleak population traits across the Iberian Penin- allowed obtaining a representative sample of bleak across the sula with which to assess the risks posed by this species to native broadest possible TL-size range from each river. Catch methods 40 species and ecosystems (Almeida et al. 2013). In particular, consisted of following a zig-zagging and upstream direction in growth and reproduction are key aspects for assessing the both banks at each site (100-m river length) by electrofishing 45 phenotypic variability of non-native fishes, which can facilitate (2000 W-pulse DC generator at 200–250 V, 2–3 A, 30 min per the invasion process (e.g.ROOF Copp and Fox 2007). However, bank), dip nets ONL (1.5-m-long pole, 30-cm-diameter net, 10-mm variations in bleak population traits have received relatively mesh size), seine nets (20 Â 2 m, 10-mm mesh size) and gill-nets 45 little study across Europe in general and in the Mediterranean (20 Â 1 m, 10-mm mesh size, 50% hanging ratio, 1.5 m deep). region in particular. The available literature on bleak autoecology Electrofishing was performed the first sampling day and nets 50 are simply relatedP to species’ spatial distribution (Vinyoles et al. were used the second day. All Iberian surveys followed the same 2007), habitat preferences (Mun˜oz-Mas et al. 2016) and a few sampling protocols (e.g. proportional effort in terms of people and population traits restricted to local scales (Almeida et al. 2014; time) to ensure comparability among the study rivers, with 50 Maso´ et al. 2016). methods being agreed and applied by each research team per The aim of the present study was to assess the inter-population river). A professional fisherman sampled for bleak in France.