Revalidation of the Argentinian pouched lamprey Geotria macrostoma (Burmeister, 1868) with molecular and morphological evidence

Background The Argentinian pouched lamprey, classified as Petromyzon macrostomus Burmeister, 1868 was first described in 1867 in De La Plata River, in Buenos Aires, Argentina, and subsequently recorded in several rivers from Patagonia. Since its original description, the validity of P. macrostomus was questioned by several ichthyologists and 36 years after its original discovery it was considered a junior synonym of Geotria australis Gray, 1851. For a long time, the taxonomic status of G. australis has been uncertain, largely due to the misinterpretations of the morphological alterations that occur during sexual maturation, including the arrangement of teeth, size and position of fins and cloaca, and the development of an exceptionally large gular pouch in males. In this study, the taxonomic status of Geotria from across the "species" range was evaluated using both molecular analysis and examination of morphological characteristics. Methodology/principal findings Phylogenetic and species delimitation analyses based on mitochondrial DNA sequences of Cytochrome b (Cyt b) and Cytochrome C Oxidase Subunit 1 (COI) genes, along with morphological analysis of diagnostic characters reported in the original descriptions of the species were used to assess genetic and morphological variation within Geotria and to determine the specific status of the Argentinian lamprey. These analyses revealed that Geotria from Argentina constitutes a well differentiated lineage from Chilean and Australasian populations. The position of the cloaca and the distance between the second dorsal and caudal fins in sub-adult individuals, and at previous life stages, can be used to distinguish between the two species. In addition, the genetic distance between G. macrostoma and G. australis for the COI and Cyt b mitochondrial genes is higher than both intra-and inter-specific distances reported for other Petromyzontiformes. Conclusions/significance Our results indicate that the Argentinian pouched lamprey, found along a broad latitudinal gradient on the south-west Atlantic coast of South America, should be named as Geotria macrostoma (Burmeister, 1868) and not as G. australis Gray 1851, returning to its earliest valid designation in Argentina. Geotria macrostoma can now be considered as the single lamprey species inhabiting Argentinian Patagonia, with distinct local adaptations and evolutionary potential. It is essential that this distinctiveness is recognized in order to guide future conservation and management actions against imminent threats posed by human actions in the major basins of Patagonia.Fil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Barrasso, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; ArgentinaFil: Baker, Cindy. National Institute Of Water And Atmospheric Research; Nueva ZelandaFil: Quiroga, Analía Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Baigún, Claudio Rafael M.. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Basso, Nestor Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentin

Maternal influence on early lipid content in an introduced partially anadromous population of rainbow trout Oncorhynchus mykiss

This study evaluated how the maternal migratory tactic in a partially anadromous population of Oncorhynchus mykiss may influence the early energetic status of their offspring. Total lipid content variation (% dry mass) of recently emerged fry caught in the Santa Cruz River, Argentina, was evaluated as a function of their maternal origin (anadromous v. resident) and fork length (LF ). Lipid content of fry decreased with LF and was higher for offspring of anadromous mothers.Fil: Liberoff, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Leal Martínez, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Díaz de Vivar, María Enriqueta Adela. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentin

Genetic signals of artificial and natural dispersal linked to colonization of South America by non-native Chinook salmon (Oncorhynchus tshawytscha)

Genetics data have provided unprecedented insights into evolutionary aspects of colonization by non-native populations. Yet, our understanding of how artificial (human-mediated) and natural dispersal pathways of non-native individuals influence genetic metrics, evolution of genetic structure, and admixture remains elusive. We capitalize on the widespread colonization of Chinook salmon Oncorhynchus tshawytscha in South America, mediated by both dispersal pathways, to address these issues using data from a panel of polymorphic SNPs. First, genetic diversity and the number of effective breeders (Nb) were higher among artificial than natural populations. Contemporary gene flow was common between adjacent artificial and natural and adjacent natural populations, but uncommon between geographically distant populations. Second, genetic structure revealed four distinct clusters throughout the Chinook salmon distributional range with varying levels of genetic connectivity. Isolation by distance resulted from weak differentiation between adjacent artificial and natural and between natural populations, with strong differentiation between distant Pacific Ocean and Atlantic Ocean populations, which experienced strong genetic drift. Third, genetic mixture analyses revealed the presence of at least six donor geographic regions from North America, some of which likely hybridized as a result of multiple introductions. Relative propagule pressure or the proportion of Chinook salmon propagules introduced from various geographic regions according to government records significantly influenced genetic mixtures for two of three artificial populations. Our findings support a model of colonization in which high-diversity artificial populations established first; some of these populations exhibited significant admixture resulting from propagule pressure. Low-diversity natural populations were likely subsequently founded from a reduced number of individuals.Fil: Gomez Uchida, Daniel. Núcleo Milenio Invasal; Chile. Universidad de Concepción; ChileFil: Cañas Rojas, Diego. Núcleo Milenio Invasal; Chile. Universidad de Concepción; ChileFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Ciancio Blanc, Javier Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Ernst, Billy. Universidad de Concepción; Chile. Núcleo Milenio Invasal; ChileFil: Aedo, Eduardo. Universidad Austral de Chile; ChileFil: Musleh, Selim S.. Universidad de Concepción; Chile. Núcleo Milenio Invasal; ChileFil: Valenzuela Aguayo, Francisca. Universidad de Concepción; ChileFil: Quinn, Thomas P.. Núcleo Milenio Invasal; Chile. University of Washington; Estados UnidosFil: Seeb, James E.. Núcleo Milenio Invasal; Chile. University of Washington; Estados UnidosFil: Seeb, Lisa W.. Núcleo Milenio Invasal; Chile. University of Washington; Estados Unido

The origin of introduced rainbow trout (Oncorhynchus mykiss) in the Santa Cruz River, Patagonia, Argentina, as inferred from mitochondrial DNA

Rainbow trout (Oncorhynchus mykiss) was first introduced into Argentinean Patagonia, the southernmostregion of South America, from the United States in 1904 and at present constitutes the most conspicuous freshwaterfish in lakes and rivers of the region. The Santa Cruz River in Southern Patagonia is the only river in the world wherea self-sustained population of introduced rainbow trout is known to have developed an anadromous run. In this study,we examined mtDNA sequence variation to identify the source of Santa Cruz River rainbow trout, providing a historicalframework to interpret the processes underlying phenotypic variation and structure of Patagonian populations. TheSanta Cruz River may harbor distinct North American stocks of rainbow trout, widely distributed around the worldduring the late 19th and early 20th centuries, but today threatened after decades of habitat loss, species introduction,and introgression from alien stocks. The mtDNA sequence data revealed that the most likely origin for wild anadromousand nonanadromous fish was the McCloud River in California. Meanwhile, a local hatchery stock, representativeof rainbow trout introduced from Denmark after 1950 and widely stocked ever since throughout Patagonia, most probablyoriginated from multiple lineages from western North America, including non-Californian populations.La truite arc-en-ciel (Oncorhynchus mykiss) a été introduite en Patagonie argentine, la région la plus australe de l’Amérique du Sud, depuis les États-Unis en 1904 et elle est actuellement le poisson d’eau douce le plus en évidence dans les lacs et rivières de la région. La rivière Santa Crux en Patagonie du Sud est la seule rivière au monde dans laquelle une population autosuffisante de truites arc-en-ciel introduites ait développé une migration anadrome. Notre étude examine la variation des séquences de l’ADN mitochondrial (ADNmt) afin d’identifier l’origine des truites arc-en-ciel de la rivière Santa Crux et elle procure ainsi un cadre historique pour l’interprétation des processus sousjacents à la variation phénotypique et à la structure des populations de Patagonie. La rivière Santa Crux peut contenir des stocks différents de truites arc-en-ciel nord-américains qui ont été largement répandus à travers le globe à la fin du 19e siècle et au début du 20e siècle, mais qui sont aujourd’hui menacés après des décennies de pertes d’habitats, d’introductions d’espèces et d’introgressions avec les stocks étrangers. D’après les données de séquences d’ADNmt, l’origine la plus probable des poissons sauvages anadromes et non anadromes est la rivière McCloud de Californie. De plus, un stock local de pisciculture, typique des truites arc-en-ciel introduites du Danemark après 1950 et ensemencées depuis lors partout en Patagonie, provient très probablement de multiples lignées de l’ouest de l’Amérique du Nord, y compris de populations d’ailleurs que la Californie.Fil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Lessa, Enrique P.. Universidad de la República; UruguayFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Antimicrobial activity of bacteriocin-producing Carnobacterium spp. isolated from healthy Patagonian trout and their potential for use in aquaculture

In this study, bacteria from the intestines of Patagonian trout displaying fish pathogen antimicrobial activity were isolated and characterized. Isolates T4, T15 and M5 showed extracellular antimicrobial activity against the fish pathogen Carnobacterium maltaromaticum CECT 4020, by the agar well diffusion assay. They were identified as Gram-positive catalase-negative bacilli belonging to the genus Carnobacterium (based on 99.93% identity with the 16S rRNA gene sequence of C. maltaromaticum DSM 20342T). After 48 hr of incubation in MRS broth, the highest antimicrobial activity titre (327,680 AU/ml) was recorded for T4, followed by T15 and M5. The antimicrobial agents produced by these isolates were thermostable peptides. LC-MS/MS peptide analysis indicated that T4 and T5 bacteriocins belonged to the class IIa. The identified peptides for T4 bacteriocin included almost the entire divercin V41 sequence, which was previously believed to be exclusively produced by Carnobacterium divergens. In addition, no negative fish health effects were observed after administrating T4 to zebrafish. Among the isolates from healthy Patagonian trout, due to its early bacteriocin production, its greater inhibition titre and its innocuous feature, Carnobacterium sp. T4 emerged as the most promising isolate for in vivo challenges targeting its further aquaculture application.Fil: Garcés, Marisa Elisabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Olivera, Nelda Lila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Fernández, Melania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Secretaría de Ciencia, Tecnología e Innovación Productiva de la Provincia de Chubut; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Sequeiros, Cynthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentin

Chinook salmon (Oncorhynchus tshawytscha, Walbaum 1792) in the Beagle Channel, Tierra del Fuego: the onset of an invasion

In this paper we provide the first report of the presence of exotic Chinook salmon (Oncorhynchus tshawytscha) in two rivers off the Beagle Channel, Lapataia and Ovando, in southern Tierra del Fuego. We also confirm that successful reproduction occurred in the fall of 2007, as we captured yearlings in freshwater. Scale pattern analyses of adult fish caught were all of the “stream” ecotype, with ages ranging between 3 and 5 (average 4.2 year). Stable isotope analysis of Ovando-Lapataia Chinook population indicates general patterns consistent with those of other populations in the region, but characteristically enriched levels of C indicates a distinct ocean feeding location as compared to Atlantic populations in the Santa Cruz River. Two different haplotypes, one identical to the unique haplotype of the Caterina River population, were found in the Ovando-Lapataia rivers, providing partial evidence for some level of contemporary segregation between these two populations. As an exotic species, Chinook salmon have been able to use the ocean as a waterway to rapidly colonize new habitats both in New Zealand and in several Pacific and Atlantic river basins of continental Patagonia. This record expands the known distribution of this species in Patagonia further south and into the Island of Tierra del Fuego. Its presence in the Beagle Channel creates the conditions for its expansion to a significant collection of new rivers, as well as to adjacent marine areas in and around the Southern Fuegian Channels. Our results provide support to the idea that, in practice, no district of Patagonia is sheltered from the colonization by invasive anadromous Salmonids.Fil: Fernandez, Daniel Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Ciancio, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Ceballos, Santiago Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentin

Caracterización del ambiente físico a distintas escalas espaciales del río Santa Cruz

La caracterización del ambiente físico de los sistemas fluviales a distintas escalas espaciales constituye un paso importante para establecer las bases de la estructura comunitaria acuática e identificar principios de conservación. Este enfoque es pertinente para aplicar en ambientes como el río Santa Cruz, uno de los últimos sistemas fluviales prístinos de la Argentina, el segundo río más caudaloso de la Patagonia y reconocido como un sistema de alta complejidad espacial. Existen proyectos para construir represas hidroeléctricas en este río, las cuales alterarán varias de las características físicas estructurales y, por ende, a las comunidades que lo habitan. Por esto es importante entender las jerarquías estructurales del hábitat natural de los ríos, que son determinadas por la geología de las cuencas a una escala regional (cientos de kilómetros) y por las variables del hábitat local (decenas de kilómetros) experimentadas por las especies acuáticas.Fil: Quiroga, Analía Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Coscarella, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Massaferro, Gabriela Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina6ta Jornada de Presentación de BecariosPuerto MadrynArgentinaCentro Nacional Patagónic

The invasion of an Atlantic Ocean river basin in Patagonia by Chinook salmon: new insights from SNPs

Chinook salmon spawning was firstreported in the 1980s in the Caterina River tributaryof the Santa Cruz River basin of Patagonia, whichdrains into the Atlantic Ocean. A naturalized populationnow persists and its source has been debated.Chinook salmon from California populations wasdirectly released into the Santa Cruz River in the earlytwentieth century, but ocean ranching experiments onthe Pacific coast of Patagonia (Chile) also releasedChinook salmon of lower Columbia River origin(University of Washington hatchery stock) in the latetwentieth century. We used genetic stock identificationwith single nucleotide polymorphisms to explorethe origin of this Chinook salmon population. Thegenotypes of salmon that invaded the Santa Cruz Riverwere compared with those derived from 69 knownpopulations from the Northern Hemisphere. ChinookSalmon of the Santa Cruz River were found to be mostsimilar to those from the lower Columbia River. Thissupports the hypothesis that the Santa Cruz Riverpopulation was founded from the ocean ranching insouthern Chile and the river was invaded by fishstraying from Pacific coast basins. Moreover, we findthat the life history of these naturalized fish, as inferredfrom scale analysis, was similar to that of theprogenitor stock. We suggest that the successfulinvasion of the Caterina River in Patagonia byChinook salmon was aided by pre-adaptations ofsome of the stocks used in the ocean ranchingexperiments to conditions in the new environment,rather than a post-colonization adaptation.Fil: Ciancio Blanc, Javier Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Anderson, Eric. University of California. Southwest Fisheries Science Center National Marine Fisheries Service; Estados UnidosFil: Garza, John Carlos. University of California. Southwest Fisheries Science Center National Marine Fisheries Service; Estados Unido

Natural Colonization and Establishment of a Chinook Salmon, Oncorhynchus tshawytscha, Population in the Santa Cruz River, an Atlantic Basin of Patagonia

We report the finding of an established population of exotic Chinook salmon spawning in headwaters of the Santa Cruz River system (Argentina), the first for this species in an Atlantic basin of South America. Spawning takes place in the Caterina River, a small tributary of Lake Argentino, located 488.5 km from the ocean. Anadromy was verified by correspondence of N and C stable isotope ratios with those of fish captured by bottom-trawlers in the ocean and those of anadromous rainbow trout from the same river basin. The scale patterns of most fish examined were consistent with a stream-type life cycle (i.e., seaward migration by juveniles after a full year in fresh water). Two potential origins were identified for this population: in situ introductions of fish imported directly from the USA in the early 20th century or fish from two ranching experiments conducted in southern Chile during the 1980s. In the latter case, colonization would have proceeded through the Strait of Magellan, helped by prevailing eastward currents.Fil: Ciancio Blanc, Javier Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Pascual, Miguel Alberto. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Lancelotti, Julio Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Botto, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Shifts in d15N signature following the onset of exogenous feeding in fishes: Importance of combining length and age data

The 15N isotopic change of recently emerged rainbow trout (Oncorhynchus mykiss) due to diet shift from yolk sac to exogenous feeding was evaluated in a field study. The fit of a general model including both fish length and age in days as co-variables indicates that the collection of isotope signatures could have arisen from a dilution process of a common maternally inherited signature. The results suggest that the specific 15N of individual fish at any given time along the ontogeny is determined by its growth trajectory and not by time or size alone. The results are discussed in the context of the potential bias in determining maternal origin in partially migratory salmonids through muscle isotope ratios based on fish size alone.Fil: Liberoff, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagonico; ArgentinaFil: Riva Rossi, Carla Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagonico; ArgentinaFil: Fogel, Marilyn. Carnegie Institution for Science; Estados UnidosFil: Ciancio Blanc, Javier Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagonico; ArgentinaFil: Pascual, Miguel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagonico; Argentin