Browsing by Author "Medina-Vogel, Gonzalo"
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- ItemCo-Occurrence Between Salmon Farming, Alien American Mink (Neogale vison), and Endangered Otters in Patagonia(2023) Medina-Vogel, Gonzalo; Calvo-Mac, Carlos; Delgado-Parada, Nicole; Molina-Maldonado, Gabriela; Johnson-Padilla, Stephanie; Berland-Arias, PauletteThe southern river otter (Lontra provocax) and the marine otter (Lontra felina) are endangered species that inhabit Chile. In southern Chile, both species cohabit with the American mink (Neogale vison), an invasive exotic species. The Chilean aquaculture industry has grown exponentially since the late 1980s, with salmon farming taking place from central Chile to the Patagonian fjords and channels. This study assessed co-occurrence between otters, mink, and aquaculture in Patagonia by (1) distributing a survey among workers, fisheries personnel, and aquaculture inspectors concerning observations of otters and mink inside or around aquaculture facilities and outcomes; and (2) a geographical assessment of distribution overlap between known otter territory and salmon farming-registered facilities. We recorded the first anecdotal evidence of interaction, described as co-occurrence, among native otters, American mink, and salmon aqua culture in Patagonia, which varied among seasons and seems to be increasing. We also recorded evidence of difficulty in recognition of the three mustelids among respondents. There is a geographically extended interaction between otters and salmon farms in Chile. The evidence of interaction among alien American mink, native endangered otters, and aquaculture is an early alarm for human-wildlife conflict, and further studies are recommended to ensure native otter conservation.
- ItemDomestic dog and alien North American mink as reservoirs of infectious diseases in the endangered Southern river otter(2022) Barros, Macarena; Pons, Daniel J.; Moreno, Andrea; Vianna, Juliana; Ramos, Barbara; Duenas, Fernando; Coccia, Cristina; Saavedra-Rodriguez, Roberto; Santibanez, Alexis; Medina-Vogel, GonzaloIntroduced alien carnivores are host to infectious diseases that may become an important threat for native carnivore species conservation. Canine distemper virus (CDV) is thought to be transmitted among individuals by direct contact and to present viral dynamics associated with a density-dependent multi-host carnivore community. In contrast, Canine Parvovirus (CPV) is mostly transmitted by indirect contact and does not depend only on the density, but also on the social behaviour of infected as well as susceptible hosts. The objective of this study was to assess how introduced American mink (Neovison vison) can act as a bridge-host between domestic dog (Canis familiaris) and Southern river otter (Lontra provocax) in different dog and mink population density scenarios. Our data show that otters are seropositive to both CDV and PV, as well as a molecular identity to Parvovirus in dogs and minks. Furthermore, a strong positive correlation between dog population density and observed seroprevalence of CDV in dogs, minks, and otters was recorded. For Parvovirus, the observed seroprevalence in mink and otters was not correlated to a higher dog population density, but instead a relationship between dog and mink population densities and social behaviour. Our results suggest that introduced American mink and domestic dogs are reservoirs of CDV and PV, both being diseases of major importance for the conservation of native endangered carnivores in Patagonia.
- ItemGenetic structure of introduced American mink (Neovison vison) in Patagonia : colonisation insights and implications for control and management strategies(2018) Mora, Mónica; Medina-Vogel, Gonzalo; Sepúlveda, Maximiliano A.; Noll, Daly; Álvarez Varas, Rocío; De Abreu, Vianna Juliana
- ItemImproving Trapping Efficiency for Control of American Mink (Neovison vison) in Patagonia(2022) Medina-Vogel, Gonzalo; Munoz, Francisco; Moeggenberg, Meredith; Calvo-Mac, Carlos; Barros-Lama, Macarena; Ulloa, Nickolas; Pons, Daniel J.; Clapperton, B. KaySimple Summary Two main challenges to control invasive mammals are to maximize campaign efficacy and cost-effectiveness, and to avoid trapping other species. We designed and tested new protocols to address those challenges to control alien American mink in southern Chile. We recommend the use of the GMV-13 variant of collapsible wire cage with scent gland lure, as they are smaller, cheaper, easier to transport and effective at catching female mink and reducing the possibility of trapping native species. Trapping campaigns using GMV-13 should be conducted principally during summer, with a 200-m trap spacing, for up to 6 days before moving traps to a new site, with a combination of three days with female scent gland lure followed by three days with male scent gland lure. Our modelling reveals that this should result in the removal of at least 70% of the local estimated discrete mink population within the area covered by each transect. Two main challenges when controlling alien American mink (Neovison vison) in Patagonia are to maximize campaign efficacy and cost-effectiveness and to avoid trapping native species. We designed and tested new variants of collapsible wire box traps, compared the efficacy of a food-based bait and a scent lure and compared catch rates in different seasons of the year. We used the data to model the efficiency rate of the trapping and to determine the trapping effort required to remove 70-90% of the estimated discrete mink population. Between January 2018 and March 2021, we operated 59 trapping transects over 103 three-day trapping periods in southern Chile. Traps were first baited with canned fish, and afterwards with mink anal gland lure. We compared the efficacy of mink capture with that of our previous study. We trapped 196 mink (125 males, 71 females), with most captures in summer. The medium-sized GMV-18 trap caught more male mink, but the more compact GMV-13 caught fewer non-target rodents and no native mammals. The scent lure was more successful than the canned fish when the previous campaign's data were included in the analysis. There was also a significant improvement in the proportion of female mink trapped and reduced labour compared with our previous campaign that used larger traps, fish bait and 400-500 m trap spacings. We caught relatively more females than males after the third night of trapping on a transect. Our data analysis supports the use of the GMV-13 variant of wire cage trap as the best trap size: it is effective on female mink, small, cheap and easy to transport. Combined with mink anal scent lure, it reduces the possibility of trapping native species compared with other traps tested in Chile. As the most efficient method for removing at least 70% of the estimated discrete mink population within the area covered by each trap transect in southern Chile tested to date, we recommend trapping campaigns using GMV-13 during summer, with a 200-m trap spacing, for up to 6 days before moving traps to a new site, with a combination of three days with a female scent gland lure, followed by three days with a male scent gland lure.
- ItemIsolation of drug-resistant Salmonella enterica serovar enteritidis strains in gentoo penguins from Antarctica(2017) Retamal, Patricio; Llanos-Soto, Sebastian; Moreno Salas, Lucila; Lopez, Juana; Vianna, Juliana; Hernandez, Jorge; Medina-Vogel, Gonzalo; Castaneda, Francisco; Fresno, Marcela; Gonzalez-Acuna, DanielAnthropogenic activity in Antarctica constitutes a continuous risk for the introduction of infectious diseases into indigenous wildlife populations. Penguin colonies living close to human settlements or inhabiting in areas considered for tourism could be facing a greater threat of infection. Fecal samples from Pygoscelis penguins (Pygoscelis spp.) were collected from different sites within Antarctic Peninsula and South Shetlands Islands in order to assess the presence of Salmonella enterica. Bacterial identification and characterization was performed applying biochemical and molecular techniques. Isolates were tested for antimicrobial resistance by the disk diffusion method, and PCR analyses were used for detection of resistance and virulence-associated genes. Four samples (1.74%) from P. papua were found to be positive to S. enterica serovar Enteritidis strains. All of them showed phenotypic antimicrobial resistance to at least three antimicrobials, and shared a similar gene profile through PCR. Results in this study urgently call for improvements in sanitary standards for waste disposal and sewage treatment in Antarctica. To our knowledge, this is the first study to report antimicrobial resistance in S. enterica isolated from Antarctic wild species.
- ItemPhylogeography of the Marine Otter (Lontra felina): Historical and Contemporary Factors Determining Its Distribution(2010) Vianna, Juliana A.; Ayerdi, Paula; Medina-Vogel, Gonzalo; Mangel, Jeffrey C.; Zeballos, Horacio; Apaza, Manuel; Faugeron, SylvainThe evolutionary history of a species can be revealed by phylogeographical analysis; nevertheless, not only historical but also contemporary processes can imprint on the distribution of genetic diversity. We report on the phylogeny of Lontra ssp. in South America, and the role of spatial heterogeneity in shaping the distribution and population structure of the endangered marine otter, Lontra felina. Analyzing a total of 2261 bp of mitochondrial DNA (mtDNA) revealed the recent divergence of L. felina from L. provocax. A strong population structure (Phi(st) = 0.83, P < 0.0001) and a significant pattern of isolation by distance were described for L. felina (n = 168) across a wide geographical distribution (13 degrees 53'S to 43 degrees 36'S). Lontra felina mtDNA phylogeny is composed of 2 main clades: a clade from Peru and another composed of Chilean haplotypes. Northern populations show different divergent lineages and higher genetic diversity when compared with more recently colonized southern populations. Furthermore, long sandy beaches seem to act as barriers to dispersal, creating 2 evolutionary significant units in agreement with subspecies previous description, and at least 5 different management units (MUs). At a fine spatial scale, the size of rocky seashore patches, the distance between patches and anthropogenic factors also play important roles in species gene flow.
- ItemPhylogeography of the Patagonian otter Lontra provocax: adaptive divergence to marine habitat or signature of southern glacial refugia?(2011) Vianna, Juliana A.; Medina-Vogel, Gonzalo; Chehebar, Claudio; Sielfeld, Walter; Olavarria, Carlos; Faugeron, SylvainBackground: A number of studies have described the extension of ice cover in western Patagonia during the Last Glacial Maximum, providing evidence of a complete cover of terrestrial habitat from 41 degrees S to 56 degrees S and two main refugia, one in south-eastern Tierra del Fuego and the other north of the Chilo, Island. However, recent evidence of high genetic diversity in Patagonian river species suggests the existence of aquatic refugia in this region. Here, we further test this hypothesis based on phylogeographic inferences from a semi-aquatic species that is a top predator of river and marine fauna, the huillin or Southern river otter (Lontra provocax).
- ItemSurgical Implantation of Intra-abdominal Radiotransmitters in Marine Otters (Lontra felina) in Central Chile(2008) Soto-Azat, Claudio; Boher, Francisca; Fabry, Mauricio; Pascual, Paulo; Medina-Vogel, GonzaloSix free-ranging marine otters (Lontra felina) were livetrapped on the central coast of Chile and implanted with specially designed radiotransmitters as part of a spatial ecology study. Marine otters frequent the rocky seashore, often squeezing their narrow bodies through cracks and crevices and grooming themselves on the rocks. They are also among the smallest of the otter species, weighing between 3.4 kg and 4.5 kg. For these reasons, the transmitter used was small, rectangular, and flat, measuring 3.5x3.2x1.0 cm. They were implanted using a ventral midline approach to minimize contact between the skin incision and sharp-edged rocks. Surgical incisions healed within 2 wk. The transmitters functioned well, but the duration varied from 62 days to 143 days instead of the 240 days predicted by the manufacturer. All six marine otters reestablished in their home ranges, and survey results suggest they survived well beyond the life of the transmitters.