Browsing by Author "Paves, Hector"

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Adenovirus Diversity in Fur Seal and Penguin Colonies of South America
    (2021) Cortes-Hinojosa, Galaxia; Adkesson, Michael J.; Cardenas-Alayza, Susana; Seguel, Mauricio; Paves, Hector; Wellehan Jr, James F. X.
    Adenoviruses are medium size non-enveloped viruses with a trend of coevolution with their hosts. We surveyed South American fur seals (Arctocephalus australis) and Humboldt penguins (Spheniscus humboldti) for adenoviruses at two sites from 2009 to 2012. Despite the common pattern of host specificity, some of the adenoviruses in our study were present in samples from unexpected host species. We identified mastade-noviruses, aviadenoviruses, and siadenoviruses in A. australis from Peru and Chile and in S. humboldti from Peru. The El Nino Southern Oscillation (ENSO) significantly reduces the productivity of the Humboldt upwelling system, which can change trophic and other ecological interactions, facilitating exposure to new pathogens. One aviadenovirus was detected in both the penguins and the fur seals, an interclass distance. This finding occurred only during the 2009 ENSO and not in 2010 or 2012. Further studies of viral diversity in sites with high-density mixed species populations are necessary to better understand viral evolution and the effect of environmental change on viral evolution and host specificity.
  • Thumbnail Image
    Item
    Kelp and dolphin gulls cause perineal wounds in South American fur seal pups (Arctocephalus australis) at Guafo Island, Chilean Patagonia
    (ROYAL SOC, 2017) Seguel, Mauricio; Munoz, Francisco; Montalva, Felipe; Perez Venegas, Diego; Paves, Hector; Gottdenker, Nicole
    During five reproductive seasons, we documented the presence, extent and origin of perineal wounds in South American fur seal pups (Arctocephalus australis) on Guafo Island, Northern Chilean Patagonia. The seasonal prevalence of perineal wounds ranged from 5 to 9%, and new cases were more common at the end of the breeding season ( February), when pups were on average two months old and were actively expelling hookworms ( pUncinaria sp). Histologically, wounds corresponded to marked ulcerative lymphoplasmacytic and histiocytic dermatitis with granulation tissue and mixed bacterial colonies. In 2015 and 2017, kelp gulls (Larus dominicanus) and dolphin gulls (Leucophaeus scoresbii) were observed picking and wounding the perineal area of marked pups. This behaviour occurred more frequently after the pups' defecation, when sea gulls engaged in consumption of pups' faeces. The affected pups usually had moderate to marked hookworm infections along with bloody diarrhoea and anaemia. Pups with severe wounds (23% of affected animals) had swollen perineal areas and signs of secondary systemic bacterial infection. We propose that seagulls on Guafo Island have learned to consume remains of blood and parasites in the faeces of pups affected by hookworm infection, causing perineal wounds during this process. We conclude that this perineal wounding is an unintentional, occasional negative effect of an otherwise commensal gull-fur seal relationship.
  • No Thumbnail Available
    Item
    Lower marine productivity increases agonistic interactions between sea lions and fur seals in Northern Pacific Patagonia
    (2022) Montalva, Felipe; Paves, Hector; Perez-Venegas, Diego; Barrientos, Karin G. E.; Valencia, Carola; Miranda-Urbina, Diego; Seguel, Mauricio
    Interspecific interactions are key drivers of individual and population-level fitness in a wide range of animals. However, in marine ecosystems, it is relatively unknown which biotic and abiotic factors impact behavioral interactions between competing species. We assessed the impact of weather, marine productivity, and population structure on the behavioral agonistic interactions between South American fur seals (SAFSs), Arctocephalus australis, and South American sea lions (SASLs), Otaria byronia, in a breeding colony of SAFS. We hypothesized that agonistic interactions between SAFSs and SASLs respond to biotic and abiotic factors such as SAFS population structure, marine productivity, and weather. We found that SASL and SAFS interactions almost always resulted in negative impacts on the social structure or reproductive success of the SAFS colony. SASL adult males initiated stampedes of SAFS and/or abducted and predated SAFS pups. Adult SAFS males abundance and severe weather events were negatively correlated with agonistic interactions between species. However, proxies for lower marine productivity such as higher sea surface temperature and lower catches of demerso-pelagic fish were the most important predictors of more frequent agonistic interactions between SAFS and SASL. Under the current scenario of decline in marine biomass due to global climate change and overfishing, agonistic interactions between competing marine predators could increase and exacerbate the negative impacts of environmental change in these species.
  • No Thumbnail Available
    Item
    Towards understanding the effects of oceanic plastic pollution on population growth for a South American fur seal (Arctocephalus australis australis) colony in Chile
    (2021) Joaquin Perez-Venegas, Diego; Valenzuela-Sanchez, Andres; Montalva, Felipe; Paves, Hector; Seguel, Mauricio; Wilcox, Chris; Galban-Malagon, Cristobal
    Entanglement of pinnipeds with plastic debris is an emerging conservation and animal welfare issue worldwide. However, the origins and long-term population level consequences of these entanglements are usually unknown. Plastic entanglement could produce a combination of wounds, asphyxiation, or inability to feed that results in the death of a certain percentage of individuals from the total population. In this research, we report on the consequent effect of plastic entanglement on population growth de-mographics in a South American fur seal (Arctocephalus australis australis) colony on Guafo Island, southern Chile. Using a stochastic matrix population model structured according to age and sex, and assuming an otherwise stable population, we explored population growth rates under five scenarios with differing rates of entanglement: A) a zero rate of plastic entanglement, B) entanglement rates (number of entangled individuals as a proportion of the total number of individuals) as observed in our study population (overall entanglement ratio of 1.2 x 10(-3)); and for the other scenarios, entanglement ratios as reported in the literature for other pinniped colonies around the world: C) 3.04 x 10(-3), D) 4.42 x 10(-2), and E) 8.39 x 10(-2). Over the 30 years forecasting period and starting with a population size of similar to 2950 individuals, the population growth rate was lower under all scenarios with rates of entanglement greater than zero (scenarios B-E). In comparison with scenario A, at the end of the 30-year period forecasted, we calculated a projected decrease in population size of between 20.34% (scenario B) and 91.38% (scenario E). These results suggest that even the lowest levels of entanglement in pinnipeds as reported in the literature might have significant effects over time on population-level dynamics. Our research offers potential insight when devising policy for the management and limitation of plastic pollution in the oceans, and indeed for the conservation and management policy of affected marine species. Furthermore, whilst there are some limitations to our methodology, it offers a straightforward and potentially useful approach for the standardized prediction of impacts at a population level of different rates of plastic pollution and entanglement and could be applied in distinct populations of the same species around the world. (C) 2021 Elsevier Ltd. All rights reserved.