Common carp Cyprinus carpio possess multiple traits that contribute to their success as an invasive species. They have been introduced across the globe, and abundant populations can have numerous negative effects. Although ecological niche-based modelling techniques have been used to predict the potential range of C. carpio invasion in U.S.A., occurrence and abundance patterns have not yet been considered on a regional scale. In the present review new locations are documented, the status of the southernmost population has been studied and the probability of new lakes and reservoirs being colonized by C. carpio has been obtained and related to environmental conditions. The new localities for C. carpio have expanded its distribution westward, into the Andean Region, and present results from the South American southernmost population have shown a well-established population. Analysis of presence data provided two principal results: (1) the probability of a site being with C. carpio can be inferred using environmental variables and (2) the probability of a site being with C. carpio is a useful tool for the prediction of future invasions. Selective fishing on the Negro basin could constitute a potential mitigation measure, decreasing the abundance of the species and thus reducing the species' potential for southward expansion. These results reinforce the idea that artisanal fisheries, food production and conservation interests should be taken into account by local government management agencies in any discussion regarding the southern distribution of C. carpio in the near future.

The introduction of salmonids in Patagonia has resulted in significant impacts on its lakes, as well as a major impact on streams, in which native fishes seem to have been displaced almost completely by rainbow trout (Oncorhynchus mykiss). Another perspective is that the introduced salmonid species have resulted in wild fish populations that sustain an economically important sport fishery. The wide distribution and high abundance of escaped farmed rainbow trout, and a clear decrease in the abundance of native and successfully introduced salmonid species in Alicura Reservoir were all observed, based on comparison of recent data and data from 1993 to 1995 corresponding to littoral gillnet captures. Thus, both native fish and introduced salmonid populations seem to have been drastically reduced in the presence of farmed fish escapees. The results of the present study regarding fish escapes deserve major consideration when making decisions about fish cage culture activities for other Patagonian reservoirs.

The ; common carp (Cyprinus carpio L.) is probably the most widely distributed freshwater fish species and is cultured on almost all continents. In South America, studies on the parasites from C. carpio are limited. The aim of the present study was to report on the macroparasites from wild C. carpio populations inhabiting the Neuquen River, which is at the southernmost distribution of C. carpio in Argentina. From spring 2011 to winter 2012, four seasonal samples of C. carpio were collected from the Neuquen River at the Ingeniero Ballester dam using gill nets. Fish were dissected and all organs were examined using microscopy. All macroparasites were determined and counted and their prevalences and mean intensities calculated. In total, 33 fish were examined and the following six parasites were recorded: the monogeneans Dactylogyrus extensus (gills) and Pseudacolpenteron sp. (in the canals of the scales along the lateral line system); the cestode Bothriocephalus sp. (intestine); the nematode Contracaecum sp. (liver and visceral fat); and the acanthocephalans Pomphorhynchus patagonicus (intestine and liver) and Polymorphus sp. (liver and wall of intestine).

-Although the interactions of exotic salmonids with native Patagonian fishes are well known, little is known about the ecology and impact of farmed fish escapees. Salmonid production in Argentina is largely concentrated in the Alicurá reservoir in north Patagonia, where fish community studies have been scarce. Here, we assess and compare the spatial distribution, body size-condition and diet of the different fish species in this reservoir. Strong vertical segregation was observed between exotic rainbow trout Oncorhynchus mykiss (both escapees and wild), dominating the littoral zone, and native Percichthys trucha which dominate the medium and deep strata. Low piscivory-benthivory and high zooplanktivory were observed for rainbow trout, both traits being uncommon at a regional scale. Escaped farmed rainbow trout (ERT) diet included abundant indigestible items along with wild prey. Higher body condition of P. trucha close to farms, as well as the regionally unprecedented high incidence of Daphnia sp. in the guts of all the species suggest that farm nutrient discharges have had significant impacts. Finally, the high body condition of ERT, together with their wild food diet and the long dispersal distance observed, demonstrate post-escape success, drawing our attention to potential upstream dispersion affecting the biodiversity and fisheries of Patagonian rivers and lakes.Keywords: aquaculture impact / freshwater salmonid / niche segregation / diet / Patagonia Résumé -Poissons indigènes et exotiques dans un réservoir de Patagonie avec aquaculture en cage de truites arc-en-ciel : utilisation des ressources spatiales et trophiques. Bien que les interactions des salmonidés exotiques avec les poissons patagoniens indigènes soient bien connues, on connaît peu l'écologie et l'impact des poissons échappés d'élevage. La production de salmonidés en Argentine est largement concentrée dans le réservoir d'Alicurá dans le nord de la Patagonie, où les études sur les communautés de poissons ont été rares. Ici, nous évaluons et comparons la répartition spatiale, la taille du corps et l'alimentation des différentes espèces de poissons dans ce réservoir. Une ségrégation verticale forte a été observée entre la truite arc-en-ciel exotique Oncorhynchus mykiss (à la fois évadée et sauvage), dominant la zone littorale et Percichthys trucha natif qui domine les couches moyennes et profondes. Un faible comportement piscivore-benthivore et un régime zooplanctivore important ont été observés pour la truite arc-en-ciel, les deux traits étant peu fréquents à l'échelle régionale. Le régime de la truite arc-en-ciel échappée des cages (ERT) comprenait des composés indigestes abondants et des proies sauvages. Un coefficient de condition élevé de P. trucha près des fermes, ainsi que l'incidence locale sans précédent de Daphnia sp. dans les estomacs de toutes les espèces suggère que les rejets de nutriments aquacoles ont eu des impacts importants. Enfin, le bon état corporel des ERT, ainsi que leur régime alimentaire et la longue distance de ...

We report the first record of the copepod Lernaea cyprinacea (Linnaeus, 1758) parasitizing Percichthys trucha (Cuvier & Valenciennes, 1840) in the Neuquén River (Patagonia, Argentina). One specimen of P. trucha was found parasitized by two females of L. cyprinacea. Our record of L. cyprinacea in Neuquén River represents an increase of the known distribution range for this invasive species, which is apparently moving upstream in the Negro River Basin. This is the first record of L. cyprinacea in Neuquén Province.

Salmonid sport fishery management in Argentinian Patagonia is usually guided by stakeholder perceptions, which do not consider the biological and ecological constraints acting upon aquatic resources. An example of this are management policies for Traful Lake, where Atlantic salmon, Salmo salar L., was actively stocked during the last decade in an attempt to change the fish assemblage structure and to create a highly valuable sport fishery. This study assesses the likelihood of these policies achieving such assemblage structure changes through the study of affluent‐stream suitability as spawning and breeding grounds, lake fish assemblage parameters, trophic diversity and possible competition due to diet overlap. This study also assesses alternative management practices through population simulations and bioenergetic modelling under diverse catch‐size limit scenarios. This study concludes that it is not advisable to try to generate a unique and distinctive sport fishery by stocking Atlantic salmon in an already renowned fishery in Northern Patagonia. Instead, a more comprehensive framework for decision‐making is suggested, involving short‐term studies that go beyond the specific problem of the target species and incorporate the whole fish assemblage using diverse approaches and modelling strategies.