Inter-annual variation in the trophic niche of Magellanic penguins Spheniscus magellanicus during the pre-molt period in the Beagle Channel

Inter-annual variations in the diets of seabirds are often a reflection of resource availability, with population dynamics and community structure implications. We investigated the trophic niche of Magellanic penguins Spheniscus magellanicus during the pre-molt stage in 6 years (2009 and 2013−2017) at Martillo Island, Beagle Channel, Argentina, using carbon and nitrogen stable isotope analysis of feathers. We found higher values in 2009 compared to the other years for both isotopes and estimated different proportions of prey in the diet of Magellanic penguins throughout the years. In 2009, penguins consumed mainly a mixture of benthic and benthopelagic fish, whereas from 2013 to 2017, the proportion of the pelagic form of squat lobster Munida gregaria, considered a key species in the Beagle Channel, increased over time and nearly dominated diets in 2017. Our results confirm that Magellanic penguins act as sentinels, reflecting shifts in the marine community of the Beagle Channel via inter-annual variation in their trophic niche and diet composition.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Polito, M.J.. State University of Louisiana; Estados UnidosFil: Pütz, K.. Antartic Research Trust; AlemaniaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentin

Trophic ecology of the Magellanic Penguin Spheniscus magellanicus in Staten Island and Beagle Channel : temporal and spatial variation and individual consistencies

El nicho trófico de una población puede segregarse entre individuos según edades, sexos, especialización individual, y entre colonias de una misma especie en distintos ambientes y/o con tamaños poblacionales diferentes. Tres colonias de pingüino de Magallanes en Tierra del Fuego (Isla Martillo, Bahía Franklin e Isla Observatorio) se encuentran en condiciones oceanográficas contrastantes y tienen tamaños poblacionales diferentes, lo que las convierte en un buen modelo para estudiar la ecología trófica de un ave marina. El objetivo principal de este estudio fue describir y comparar el nicho trófico (inferido a través del nicho isotópico) de este pingüino en las tres colonias. Se determinaron los valores de δ^13C y δ^15N en sangre y plumas y se evaluaron diferencias entre sexos, edades, colonias y etapas. Se combinaron los análisis de nicho isotópico con análisis de exposición al mercurio (Hg) en las tres colonias. Se evaluaron consistencias individuales, aprovisionamiento selectivo y variaciones inter-anuales en el nicho isotópico en Isla Martillo. Durante la etapa pre-muda, el análisis isotópico y de Hg, mostró que las tres colonias utilizan áreas de forrajeo diferentes y/o de diferentes extensiones. Además de un gradiente isotópico desde el interior del Canal Beagle hacia aguas oceánicas, existe un gradiente creciente en la [Hg] en el mismo sentido. Durante el cuidado temprano de pichones se observó segregación en el nicho entre adultos, pichones y juveniles entre colonias, que reflejó el uso de áreas de alimentación cercanas a cada colonia. Durante toda la temporada de cría, se observó una alta variabilidad intra-familiar, ausencia de aprovisionamiento selectivo y ausencia de consistencia individual que reflejaron cambios en el consumo de presas y en las áreas utilizadas entre etapas. Durante la dispersión invernal, se observó que la especie utilizó extensas áreas de la plataforma patagónica (desde los 54°S hasta los 38°S), y presentó una segregación sexual latitudinal que se correlacionó con valores isotópicos diferentes, pero con iguales posiciones tróficas. Por último, se encontró una variación histórica en el nicho isotópico que correlacionó con cambios en la composición de la dieta hacia presas de menor nivel trófico más disponibles en los últimos años. Este trabajo proporciona información esencial para la toma de decisiones dirigidas a la conservación de las especies y la planificación marina espacial.The trophic niche of a population can be segregated among individuals according to ages, sexes, individual specialization, and between colonies of the same species in different environments and/or with different population sizes. Three Magellanic penguin colonies in Tierra del Fuego (Martillo Island, Franklin Bay and Observatorio Island) are in contrasting oceanographic conditions and have different population sizes, which turn them into a good model for studying trophic ecology in a seabird. The main objective of this study was to describe and compare the trophic niche (inferred through its isotopic niche) in the three colonies. We determined the values of δ^13C and δ^15N in blood and feathers and evaluated differences between and within sexes, ages, colonies and stages. We combined isotopic niche analysis with mercury (Hg) exposure analysis in the three colonies. We assessed individual consistency, selective provisioning and inter-annual variations in the isotopic niche in Martillo Island. During the pre-molt stage, the isotopic and Hg analysis showed that the three colonies use different foraging areas and/or different extensions. In addition to an isotopic gradient from the interior of the Beagle Channel to oceanic waters, there is an increasing gradient in [Hg] in the same direction. During early chick-rearing, we observed segregation in the niche among adults, chicks and juveniles between colonies, which reflected feeding areas close to each colony. Throughout the whole chick-rearing, we observed high intra-family variability, absence of selective provisioning, and absence of individual consistency that reflected changes in the consumption of prey and in the areas used between stages. During the winter dispersion, we observed that the species used large areas of the Patagonian shelf (from 54°S to 38°S), and presented a latitudinal sexual segregation that correlated with different isotopic values but with the same trophic positions. Finally, we found an historical variation in the isotopic niche that correlated with changes in the diet composition towards prey at lower trophic levels, more available in recent years. This work provides essential information for decision making targeting the conservation of the species and spatial marine planning.Fil: Dodino, Samanta Graciela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Stable isotope values of carbon and nitrogen on plasma samples collected from family’ groups (females, males and chicks) of Magellanic penguins at Martillo Island, Tierra del Fuego, Argentina

We sampled blood plasma of family’ groups (females, males and chicks) of Magellanic penguins (Spheniscus magellanicus) from Martillo Island, Argentina. We used stable isotope analyses on plasma samples to examine food provisioning, isotopic niche, trophic position and diet composition of penguins between the early and late chick-rearing period. This dataset was collected in the framework of the following publication: Variation in the trophic niche and food provisioning between the early and late chick-rearing stages in Magellanic penguins Spheniscus magellanicus at Martillo Island, Tierra del Fuego, Argentina, Dodino S., Riccialdelli L., Polito M., Pütz, Raya Rey A, Marine Biology. Accepted.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Year-round colony attendance patterns for the Gentoo Penguin (Pygoscelis papua) at Martillo Island, Tierra del Fuego, Argentina

Long-term monitoring of seabird breeding cycles and breeding success is essential for conservation and a valuable indicator of ecological change, but is logistically expensive and time consuming. We describe the annual cycle and year-round colony attendance patterns for Gentoo Penguins Pygoscelis papua at Martillo Island, Beagle Channel, by analyzing camera trap photographs. We deployed a Reconyx HC500 Hyperfire trail camera programmed in time-lapse mode to take single pictures once per hour year-round (27 Feb 2013 until 27 Feb 2014). The nonreproductive stage began 23 April 2013 when adults completed molt and ended 24 September 2013 when the first pair formation was observed. In general Gentoos Penguins performed daily trips, and the number of adults present at 1900 h ART was not significantly different at any stage except the late chick-rearing and premolt stages. Breeding success was 0.92 chicks per nest. Small variations in day length had a significant influence on penguin's trip duration during the nonreproductive stage. The method proved to be effective for monitoring this species and provided important data for management and conservation.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Hart, Tom. University of Oxford; Reino UnidoFil: Harris, Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentin

Variation in the trophic niche and food provisioning between the early and late chick-rearing stages in Magellanic penguins Spheniscus magellanicus at Martillo Island, Tierra del Fuego, Argentina

Variation in the foraging niche and parental provisioning behaviors of breeding seabirds have the potential to afect population dynamics (e.g. foraging success, breeding productivity, and ultimately population size). We sampled blood plasma of family’ groups (females, males, and chicks) of Magellanic penguins (Spheniscus magellanicus) from Martillo Island, Argentina. We used stable isotope analyses on plasma samples to examine food provisioning, isotopic niche, trophic position, and diet composition of penguins between the early and late chick-rearing periods. We found clear diferences in the isotopic niches of penguins between the two stages of the chick-rearing period related to shifts in foraging habitat and/or diet composition between stages. We found no evidence of individual consistency in isotopic niches or sex-specifc selective provisioning by adults. In addition, we found high variability within family groups (accounting for 90% of the total isotopic variability). This study improves our understanding of the age, sex, individual, and breeding stage-specifc trophic niches of Magellanic penguins, which may be helpful in projecting how they may respond to future environmental change (e.g., changes that afect prey availability).Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Polito, Michael J.. Louisiana State University Health Sciences Center New Orleans (lsu Health);Fil: Pütz, Klemens. Antarctic Research Trust; AlemaniaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Winter dispersal of Magellanic penguins at Martillo Island: Sexual differences in movement patterns and trophic ecology

The dispersal of penguins during the non-breeding period is a critical period that can affect breeding success and survival in the following season. Thus, knowledge of penguin foraging ecology during this energy-intensive period is crucial to understand their responses to ecosystem variability. We recorded winter dispersal of Magellanic penguins Spheniscus magellanicus from Martillo Island (Beagle Channel, Argentina) using LAT2900 geolocators in 2017. We collected whole blood samples when the penguins first arrived at the colony in spring to study their pre-breeding foraging niche using stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. In total, 26 adults were equipped after their annual molt, of which 24 were re-captured. However, only 20 were still equipped with devices and only 9 datasets could be recovered successfully. We found that penguins dispersed north along the Patagonian coast up to just south of Buenos Aires, Argentina (0.05), with females also having larger isotopic foraging niche widths (SEAb) relative to males. Differences in the spatial distribution and isotopic values between sexes likely reflect a pattern of niche partitioning during the non-breeding period. These results provide insights into mechanisms that may reduce intraspecific competition and can possibly inform sex-specific conservation strategies during the non-breeding period.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Polito, Michael. Department Of Oceanography And Costal Sciencies; Estados UnidosFil: Pütz, Klemens. Antartic Research Trust; Alemania10th International Penguin ConferenceDunedinNueva ZelandaUniversity of Otag

Intraspecific trophic variation during the early chick-rearing period in Magellanic penguins Spheniscus magellanicus: Influence of age and colony location

Intraspecific competition for food resources has the potential to be high for central-place foragers such as penguins and can result in spatial and dietary foraging niche segregation among individuals of the same species. We sampled adults, chicks, and juvenile individuals’ whole blood from three colonies of Magellanic penguins (Spheniscus magellanicus) from Tierra del Fuego along an inshore-offshore corridor. We analyzed the isotopic niche, the trophic position and the diet composition in penguins to investigate intraspecific trophic niche variation in relation to biological (age of individuals) and external factors (foraging habitats, colony location) using carbon (δ13C) and nitrogen (δ15N) stable isotope values. We found isotopic niche segregation between age classes within each colony. When comparing across colonies, only juvenile exhibited some degree of isotopic niche overlap among colonies. In addition, at all three colonies juveniles had the largest isotopic niches with relatively higher variation in δ13C values. All individuals consumed low trophic position (TP) prey items such as the pelagic form of Munida gregaria based on stable isotope mixing model results. Adults and juveniles incorporated high TP (silverside and nototheniids) prey items into their diets, except for juveniles from Martillo Island whose proportions mirror chicks’ values. These results denote that parents consumed different prey items for themselves than for their chicks. Intraspecific trophic niche partitioning between colonies showed a decreasing δ13C and δ15N values from the nearest inshore colony relative to the farther offshore colonies. Understanding within and between colonies foraging strategies are important to set up connectivity between populations, status of the different colonies, and to develop adequate conservation actions.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Polito, Michael J.. State University of Louisiana; Estados UnidosFil: Pütz, Klemens. Antarctic Research Trust; AlemaniaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Uso de vertederos, mortalidad y exposición a microplásticos en rapaces de Ushuaia, provincia de Tierra del Fuego, Sur de Argentina

Los desechos orgánicos en los basureros sirven como un subsidio alimenticio de fácil obtención para muchas especies en todo el mundo, con una variedad de efectos tanto positivos como negativos en los parámetros reproductivos y de salud de los animales. Sin embargo, en algunas regiones, como el sur de la Patagonia, este fenómeno permanece sin estudiar. En Ushuaia, provincia de Tierra del Fuego, Argentina, se han registrado siete especies de rapaces carroñeras facultativas y obligadas utilizando el basurero. Durante noviembre de 2018 a septiembre de 2019, evaluamos el uso de basureros estacionales por rapaces carroñeros obligados y facultativos en Ushuaia, Argentina, y registramos abundancia, eventos de mortalidad e ingestión de microplásticos. Observamos hasta 225 rapaces de cinco especies alimentándose en la zona de depósito del basurero, con un aumento general cuatro veces mayor a principios del invierno en comparación con las otras temporadas. Registramos 17 aves rapaces muertas de tres especies e identificamos disparos, enredos, ingestión de plástico y electrocución como las causas de mortalidad. Incluso en las muestras recolectadas de aves de control no asociadas con el basurero, el 80-90% de las muestras de excretas contenían microplásticos. Sugerimos que las aves rapaces en el basurero de Ushuaia pueden servir como especies centinelas para los programas de monitoreo ambiental, lo que puede facilitar la gestión de la conservación basada en la evidencia.Organic waste in garbage dumps serves as an easily obtained food subsidy for many species globally, with a variety of both positive and negative effects on animals' reproductive and health parameters. However, in some regions, such as southern Patagonia, this phenomenon remains unstudied. In Ushuaia, Tierra del Fuego province, Argentina, seven species of facultative and obligate scavenging raptors have been recorded using the garbage dump. During November 2018 to September 2019, we assessed seasonal garbage dump use by facultative and obligate scavenging raptors in Ushuaia, Argentina, and recorded abundance, mortality events, and microplastic ingestion. We observed up to 225 raptors of five species foraging in the deposit zone of the garbage dump, with a fourfold overall increase in early winter compared to the other seasons. We recorded 17 dead raptors of three species, and we identified shooting, entanglement, plastic ingestion, and electrocution as the causes of mortality. Even in samples collected from control birds not associated with the garbage dump, 80-90% of the excreta samples contained microplastics. We suggest that raptors at the Ushuaia garbage dump may serve as sentinel species for environmental monitoring programs, which can facilitate evidence-based conservation management.Fil: Bouker, Grace. College Of Wooster,; Estados UnidosFil: Tyree, Arden. School For International Training; Estados UnidosFil: San Martín, Analía Anahí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Salom, Amira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Balza, Ulises. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Mercury exposure driven by geographic and trophic factors in Magellanic penguins from Tierra del Fuego

Penguins accumulate mercury due to their long-life span together with their high trophic position. We sampled adult and juveniles' feathers from three colonies of Spheniscus magellanicus from Tierra del Fuego along an inshore-offshore corridor. We integrated toxicological information (mercury concentrations) and foraging biomarkers (δ13C, δ15N) into a common data analysis framework (isotopic niche analysis) to evaluate the influence of age, location, and foraging behaviors on mercury concentrations. Adults had higher feather mercury concentrations, δ13C, and δ15N values compared to juveniles. Also, adult and juvenile feather mercury concentrations differed between colonies, with lower mercury concentrations at the nearest inshore colony relative to the farther offshore colonies. Trophic position and the isotopic niche analyses suggest that this geographic gradient in mercury concentrations is due to differences in colonies' foraging areas. Understanding penguins' exposure to mercury derived from local food webs is a crucial first step in evaluating the impacts of this heavy metal on their conservation status.Fil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Polito, Michael J.. Louisiana State University; Estados UnidosFil: Pütz, Klemens. Antarctic Research Trust; Estados UnidosFil: Brasso, Rebecka L.. Weber State University; Estados UnidosFil: Raya Rey, Andrea Nélida. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Mercury and stable isotopes portray colony-specific foraging grounds in southern rockhopper penguins over the Patagonian Shelf

Mercury pollution is a serious global environmental issue and the characterization of its distribution and its driving forces should be urgently included in research agendas. We report unusually high mercury (Hg) concentrations (>5 μg/g) along with stable isotopes values in feathers of southern rockhopper penguins (Eudyptes chrysocome) from colonies in the Southwest Atlantic Ocean. We found a highly heterogenous prevalence of Hg throughout the study area and over a three-fold higher mean Hg concentration in southernmost colonies. Variation in Hg concentrations among colonies is primarily explained by site, rather than by trophic position. We provide further support to the existence of a Hg hotspot in the food web of the Patagonian Shelf and spatially restrict it to the southern tip of South America. Our findings highlight the need for regional and colony-based seabird conservation management when high local variability and plasticity in foraging habits is evident.Fil: Lois, Nicolás Alejandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Balza, Ulises. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Brasso, Rebecka. Weber State University; Estados UnidosFil: Dodino, Samanta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Pütz, Klemens. Antarctic Research Trust; Islas MalvinasFil: Polito, Michael J.. Louisiana State University ; Estados UnidosFil: Riccialdelli, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Ciancio Blanc, Javier Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Quillfeldt, Petra. Justus Liebig Universitat Giessen; AlemaniaFil: Mahler, Bettina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Raya Rey, Andrea Nélida. Wildlife Conservation Society; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin