caa a22 4500 606228063 CHVBK 20210128101201.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s10641-014-0360-6 doi (NATIONALLICENCE)springer-10.1007/s10641-014-0360-6 A natural experiment of dietary overlap between introduced Rainbow Trout ( Oncorhynchus mykiss) and native Puyen ( Galaxias maculatus ) in the Santa Cruz River, Patagonia [Elektronische Daten] [Marina Tagliaferro, Ivan Arismendi, Julio Lancelotti, Miguel Pascual] Diet overlap between the native Puyen (Galaxias maculatus) and juvenile exotic Rainbow Trout (Oncorhynchus mykiss) was studied in 52 sites located along 306km of the mainstem of the Santa Cruz River, one of the largest rivers in Patagonia. The relative abundance of both species varied along the river, with three clearly defined areas including an upstream "high Rainbow Trout to Puyen ratio” area (with abundances of 75 and 25%, respectively), a midstream "intermediate Rainbow Trout to Puyen ratio” area (relative abundances between 75 and 25%), and a downstream "low Rainbow Trout to Puyen ratio” area. The diet of the 2 species was analyzed across these 3 areas examining stomach content. Diet similarity between species was analyzed using a non-metric multidimensional scaling ordination technique; prey electivity was evaluated with the Ivlev's Index; feeding tactics were studied by estimating prey-specific abundance. Both species showed a generalist feeding tactic, with Puyen exhibiting a more varied diet. Prey electivity was similar in both species, with the mayfly (Meridialaris chiloeensis), stoneflies (Klapopteryx kuscheli and Antarctoperla michaelseni), and the amphipod (Hyalella sp.) being the most frequently consumed prey. A significant diet overlap was found only in the downstream areas where a higher proportion of native fish occurs. The low diet overlap in upstream locations might be because of the high density of Rainbow Trout; while mid-stream could be due to the high secondary productivity spots. Our results suggest that the diet of native Puyen changed in relation to the abundances of Rainbow Trout in the stream. Springer Science+Business Media Dordrecht, 2014 Trout invasion nationallicence Galaxiids nationallicence n-MDS nationallicence Feeding tactics nationallicence Tagliaferro Marina División de Ciencias Básicas - Universidad Nacional de Luján. Ruta 5 y Av. Constitución, (6700), Luján, Buenos Aires, Argentina aut Arismendi Ivan Department of Fisheries and Wildlife, Oregon State University, 3200 SW Jefferson Way, 97331, Corvallis, OR, USA aut Lancelotti Julio CONICET, Centro Nacional Patagónico, Bld. Brown 2915, Puerto Madryn, Chubut, Argentina aut Pascual Miguel CONICET, Centro Nacional Patagónico, Bld. Brown 2915, Puerto Madryn, Chubut, Argentina aut Environmental Biology of Fishes Springer Netherlands 98/5(2015-05-01), 1311-1325 0378-1909 98:5<1311 2015 98 10641 https://doi.org/10.1007/s10641-014-0360-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10641-014-0360-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tagliaferro Marina División de Ciencias Básicas - Universidad Nacional de Luján. Ruta 5 y Av. Constitución, (6700), Luján, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Arismendi Ivan Department of Fisheries and Wildlife, Oregon State University, 3200 SW Jefferson Way, 97331, Corvallis, OR, USA aut NATIONALLICENCE 700 1- Lancelotti Julio CONICET, Centro Nacional Patagónico, Bld. Brown 2915, Puerto Madryn, Chubut, Argentina aut NATIONALLICENCE 700 1- Pascual Miguel CONICET, Centro Nacional Patagónico, Bld. Brown 2915, Puerto Madryn, Chubut, Argentina aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Springer Netherlands 98/5(2015-05-01), 1311-1325 0378-1909 98:5<1311 2015 98 10641