Examinando por Autor "Garcia-Cegarra, Ana M"
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Ítem Heavy metals and trace elements in a threatened population of guanay cormorants (Leucocarbo bougainvilliorum) from an industrialized bay in the Humboldt Current System, Chile(Elsevier GmbH, 2025) Carretero, Jorge; Garcia-Cegarra, Ana M; Martinez-Lopez, EmmaMetal contamination from industrial and mining activities threatens coastal and marine ecosystems, leading to bioaccumulation in marine organisms and biomagnification through the trophic chain. The Guanay cormorant (Leucocarbo bougainvilliorum), an endemic species of the Humboldt Current System, is experiencing population declines and serves as a key bioindicator of heavy metal contamination due to its high trophic position, reliance on commercially exploited pelagic fish, and capacity to accumulate contaminants over time. This study analyzed the concentrations of five heavy metals (Hg, As, Pb, Cr, Cd) and three trace elements (Cu, Zn, Se) in liver, muscle, feathers, and kidney of 10 Guanay cormorants found dead in Mejillones Bay, Chile, a highly industrialized area. Feathers exhibited the highest concentrations of Cr (2.03 ± 0.63 mg/kg), Cu (19.72 ± 3.82 mg/kg), and Zn (109.84 ± 11.95 mg/kg), emphasizing their role in detoxification. Females showed significantly higher Cu and Pb concentrations in muscle and Cr in kidneys, likely due to physiological and hormonal differences related to reproduction. Correlations between metal concentrations across tissues suggest shared bioaccumulation mechanisms, while the Hg:Se molar ratio (e.g., 0.25 ± 0.04 in liver) indicated a protective role of Se against Hg toxicity. Metal concentrations were comparable to those reported in other marine cormorants but differed from freshwater populations, highlighting the influence of habitat on metal accumulation. Although current levels do not indicate acute toxicity, the ongoing population decline of Guanay cormorants underscores the need for long- term biomonitoring. Future research incorporating biochemical and enzymatic biomarkers is essential to assess potential sublethal effects and long-term ecological risks associated with heavy metal exposure in this species.Ítem High rate of ship strike to large whales off Chile: Historical data and proposed actions to reduce risk(Elsevier, 2025) Toro, Frederick; Buchan, Susannah J; Alvarado-Rybak, Mario; Bedrinana-Romano, Luis; Garcia-Cegarra, Ana M; Hucke-Gaete, Rodrigo; Olavarria, Carlos; Sepulveda, Maritza; Galletti-Vernazzani, Barbara; Sielfeld, Walter; Aguayo, Anelio; Capella, Juan; Perez-Alvarez, Maria Jose; Viddi, Francisco; Caceres, Benjamin; Gibbons, Jorge; Acevedo, Jorge; Guzman, Hector; Guerra, Jorge; Saez, Ricardo; Seguel, Mauricio; Fishbach, M. MichaelShip strikes are a worldwide threat to large whales as a major cause of mortality and injury. In the Southeast Pacific, this has been poorly studied. In the last decade, an increase in ship strikes has been observed off Chile. This study assesses ship strike mortality in large whales off Chile using data on fatal strandings from the past 52 years, (1972-2023) and vessel traffic patterns. In 63 out of 226 strandings (28 %), ship strike was the direct or probable cause of mortality, i.e. the primary cause of non-natural death in whales. Fin whales (B. physalus) suffered highest total ship strikes (n = 23; 37%), followed by humpback (M. novaeangliae) (n =13; 21 %), blue whales (B. musculus) (n = 7; 11 %), sei (B. borealis) and sperm whales (P. macrocephalus) (n = 6; 10 %). Ship strikes were highest in the Regions of Valparaiso, Coquimbo, Atacama and Antofagasta (Central-Northern Chile), Los Lagos, Aysen and Magallanes (Southern Chile). Since 2013, when necropsies began to be systematically performed, an average of 5 individuals/year have been killed by ships, mostly between January and May. We review all ship strike studies globally and compare rates in Chile with those elsewhere. Based on data between 2013 and 2023, Chile is the country with the highest ship strike mortality globally; considering the entire time series since 1972, Chile ranks number six worldwide. We identify major knowledge gaps and recommend policy measures, including establishing High-Risk Areas and the implementation of shipping lanes modifications and vessel speed restrictions.Ítem Pingers as a potential deterrent tool to mitigate Burmeister's porpoise (Phocoena spinipinnis) bycatch while foraging nocturnally in the Humboldt Current System: a pilot study(Frontiers Media SA, 2025) Diaz, Diego; Garcia-Cegarra, Ana MFisheries bycatch is one of the main threats for porpoise species worldwide. In the Humboldt Current system of northern Chile, the elusive Burmeister’s porpoise (Phocoena spinipinnis) inhabits the coastal waters of Mejillones Bay and suffers bycatch mortality in purse seine fishing nets and coastal gillnets. In order to mitigate bycatch of this near-threatened species, this study aimed to (1) analyze the diurnal and nocturnal acoustic behaviors of the Burmeister’s porpoise and (2) evaluate the potential of banana pingers as acoustic deterrent tools. For 27 days during austral summer, a full wave form capture porpoise detector was anchored 7 m above sea level in Mejillones Bay where Burmeister’s porpoises are frequently observed. During this time, the detector registered acoustic activity continuously over 13 days, and a banana pinger deployed over 100 m away from the detector emitted high frequency sounds continuously for 14 days. The results show that the number of clicks and detection-positive minutes were significantly higher while the inter-click intervals and high click rate feeding buzz were significantly lower at night, indicating that Burmeister’s porpoises forage mainly nocturnally in this bay. With pingers present, the probability of detection of Burmeister’s porpoise acoustic activity decreased by 20%, suggesting that pingers could be an effective tool to avoid Burmeister’s porpoise mortality in fishing nets. Future studies should implement pingers in artisanal purse seine fishing nets and coastal gillnets in order to mitigate Burmeister’s porpoise bycatch in northern Chile.Ítem Site fidelity and external health of two distinct fin whale populations from the Northeast and Southeast Pacific Ocean(Elsevier GmbH, 2025) Guevara, Consuelo; Arriagada, Aracelli; Fishbach, Michael; Van Bressem, Marie-Francoise; Van Waerebeek, Koen; Garcia-Cegarra, Ana MHuman activities such as marine traffic, fishing, and pollution are the main threats to large cetaceans, especially to resident whale populations inhabiting heavily exploited enclosed seas or gulfs. Skin is indicative of whale health status because it can display wounds and scars from interactions with fishing gear, boat strikes and natural predators as well as infectious diseases. We evaluated the residence time of two fin whale, Balaenoptera physalus (Linnaeus, 1758) populations: one resident in the Gulf of California (GC), Mexico, and another potentially migratory found at Mejillones Peninsula (MP), Chile. We also compared skin conditions by analyzing photographs for the period 2016–2022. The results show that the GC population is closed while the MP population has a low residence time (5–6 months). The GC population has a significantly higher prevalence of the mesoparasite Pennella sp., commensal Xenobalanus globicipitis and scars from collision with vessels than its MP counterpart. The MP population has a significantly higher prevalence of skin conditions of natural origin such as cookie-cutter shark (Isistius sp.) bites, predation by killer whales, Orcinus orca (Linnaeus, 1758), and orange-brown and green–brown diatom patches than the GC population. These results show that a fin whale population residing year-round in an area with high industrial, fishing, and marine traffic presents more skin conditions related to anthropogenic origin than an oceanic migratory population, which mainly presents scars of natural origins (predation). It is recommended to review the conservation status of the GC resident fin whale population and propose management strategies to guarantee their long-term conservation and welfare.