Surface pauses in relation to dive duration in imperial cormorants; how much time for a breather?

Air-breathing animals diving to forage can optimize time underwater by diving with just enough oxygen for the projected performance underwater. By so doing they surface with minimal body oxygen levels, which leads to maximal rates of oxygen uptake. We examined whether imperial cormorants Phalacrocorax atriceps adhere to this by examining dive:pause ratios in birds diving for extended, continuous periods to constant depths, assuming that the oxygen used underwater was exactly replenished by the periods at the surface. Examination of the cumulative time spent in surface pauses relative to the cumulative time spent in diving showed that surface pauses increase according to a power curve function of time spent in the dive or water depth. In a simplistic model we considered the rate at which birds expended energy underwater to be constant and that the rate of oxygen replenishment during the surface pause was directly proportional to the oxygen deficit. We then worked out values for the rate constant for the surface pause before using this constant to examine bird body oxygen levels immediately pre- and post dive. The model predicted that imperial cormorants do not submerge with just enough oxygen to cover their projected dive performance but rather dive with substantial reserves, although these reserves decrease with increasing dive depth/duration. We speculate that these oxygen reserves may be used to enhance bird survival when rare events, such as the appearance of predators or discovery of large prey requiring extended handling time, occur. The form of the oxygen saturation curve over time at the surface means that the time costs for maintaining constant oxygen reserves become particularly onerous for long, deep dives, so the observed decrease in reserves with increasing dive duration is expected in animals benefiting by optimizing for time

Inter and intraspecific variation of the breathing cycle during diving in three species of patagonian cormorants

En tres sitios de nidificación ubicados en la costa patagónica de Argentina (Punta Loma, Caleta Malaspina y Puerto Deseado) se estudió en forma comparada la variación inter e intraespecífica de la relación entre la duración de los buceos y los intervalos de recuperación en superficie de tres especies de cormoranes: el Cormorán Imperial (<i>Phalacrocorax atriceps</i>), el Cormorán Cuello Negro (<i>Phalacrocorax magellanicus</i>) y el Cormorán Gris (<i>Phalacrocorax gaimardi</i>). El Cormorán Imperial presentó la mayor capacidad de buceo, tanto en términos de valor promedio como máximo de duración de buceo. Las duraciones de buceo promedio observadas en el Cormorán Cuello Negro y en el Cormorán Gris fueron similares entre sí y un 55% y 74% inferiores a los del Cormorán Imperial, respectivamente. Los intervalos de recuperación en superficie difirieron entre especies y presentaron un patrón similar al observado en la duración del buceo. Si bien el intervalo de recuperación en superficie aumentó linealmente en relación a la duración del buceo en las tres especies, se observó una marcada variación intraespecífica al analizar las distintas colonias de Cormorán Cuello Negro. En el Cormorán Imperial el intervalo de recuperación en superficie aumentó en función de la duración del buceo a una tasa entre cinco y ocho veces mayor a la registrada en las otras dos especies. La existencia de diferencias inter e intraespecíficas en la relación entre ambas variables resultó dependiente de la localidad estudiada, respondiendo posiblemente a las características ecológicas y ambientales de las áreas marinas adyacentes a las colonias donde los cormoranes se alimentan.In three nesting sites of the Patagonian coast of Argentina (Punta Loma, Caleta Malaspina and Puerto Deseado) we performed a comparative study of interand intraspecific variation of the relationship between dive duration and intervals at surface in three species of Patagonian cormorants: the Imperial Shag (<i>Phalacrocorax atriceps</i>), the Rock Shag (<i>Phalacrocorax magellanicus</i>) and the Red-Legged Shag (<i>Phalacrocorax gaimardi</i>). The Imperial Shag presented the highest diving capacity in terms of mean and maximum dive duration. The mean dive duration of the Rock Shag and the Red-Legged Shag were similar, and were 55% and 74% lower than that of Imperial Shag, respectively. Intervals at surface differed among species and showed a pattern similar to the observed for dive duration. Although intervals at surface increased linearly with dive duration in the three species, we observed a marked intraspecific variation when analyzing different colonies for the Rock Shag. The Imperial Shag increased intervals at surface in relation to dive duration to a rate between five and eight times higher than the other two species. Inter and intraspecific differences in the relationship between these variables were dependent on the studied locality, likely in response to the ecological and environmental characteristics of the marine areas exploited by the birds to feed

Plasma Biochemistries and Morphometric Indices of Body Condition in Imperial Cormorant (Phalacrocorax atriceps) Chicks

Plasma biochemistries provide a complementary method for assessing physiological and nutritional status of free-ranging wild birds. Triglycerides, total protein and alkaline phosphatase were determined in 110 free-living Imperial Cormorant (Phalacrocorax atriceps) chicks aged 16-35 days, at Punta León (Argentina) during 2010 and 2011. Body mass at 30 days of age ("pre-fledging body condition", 2010 only) and body mass corrected by tarsus length at the time of blood sampling ("current body condition", 2011 only) were also determined. Variability of parameters by sex, hatching order, survival, age and breeding season was assessed, and the relationship between biochemical and morphometric indices was also explored. Morphometric indices were higher in A-chicks (pre-fledging body condition also varied with sex), and explained 35-55% of B-chick survival. Biochemistries differed significantly between breeding seasons, being higher in 2011. Alkaline phosphatase increased with age, and total protein was higher in A-chicks. Triglycerides and total protein accounted for 26% and 30%, respectively, of variation in current body condition; however, they did not forecast pre-fledging body condition. Lastly, total protein levels predicted B-chick survival (higher levels in surviving B-chicks), but their prognostic value was relatively low. The results suggest that unlike morphometric indices, the biochemistries chosen are valuable to assess individual body condition at the time of sampling, yet their applicability for predicting chick survival requires further evaluation.Fil: Gallo, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Quintana, Flavio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Svagelj, Walter Sergio. 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 Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Uhart, Marcela María. University of California; Estados Unido

Selfies of imperial cormorants (Phalacrocorax atriceps): What is happening underwater?

During the last few years, the development of animal-borne still cameras and video recorders has enabled researchers to observe what a wild animal sees in the field. In the present study, we deployed miniaturized video recorders to investigate the underwater foraging behavior of Imperial cormorants (Phalacrocorax atriceps). Video footage was obtained from 12 animals and 49 dives comprising a total of 8.1 h of foraging data. Video information revealed that Imperial cormorants are almost exclusively benthic feeders. While foraging along the seafloor, animals did not necessarily keep their body horizontal but inclined it downwards. The head of the instrumented animal was always visible in the videos and in the majority of the dives it was moved constantly forward and backward by extending and contracting the neck while travelling on the seafloor. Animals detected prey at very short distances, performed quick capture attempts and spent the majority of their time on the seafloor searching for prey. Cormorants foraged at three different sea bottom habitats and the way in which they searched for food differed between habitats. Dives were frequently performed under low luminosity levels suggesting that cormorants would locate prey with other sensory systems in addition to sight. Our video data support the idea that Imperial cormorants' efficient hunting involves the use of specialized foraging techniques to compensate for their poor underwater vision.Fil: Gómez Laich, Agustina Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Yoda, Ken. Nagoya University; JapónFil: Zavalaga, Carlos. Universidad Científica del Sur; Perú. Nagoya University; JapónFil: Quintana, Flavio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Wildlife Conservation Society; Estados Unido

Abundance and diversity of waterbirds in a marine wetland of Golfo San jorge, Argentina

Se estudiaron la diversidad y la abundancia de aves acuáticas que utilizaron los ambientes intermareales y aguas someras de la caleta Malaspina, Golfo San Jorge, Chubut, mediante conteos semanales durante la primavera de 2000. Para esto se ubicaron siete estaciones de muestreo en ambientes intermareales representativos de la heterogeneidad ambiental presente a lo largo de la línea de costa de la caleta. El ensamble estuvo compuesto por 31 especies y mostró una alta diversidad específica de aves acuáticas. La composición del ensamble mostró un núcleo de especies dominantes y muchas especies con abundancias menores, y varió a lo largo del estudio, debido principalmente a la disminución en abundancia de la Gaviota Cocinera (<i>Larus dominicanus</i>) y a la llegada de los primeros pulsos migratorios del Playerito Rabadilla Blanca (<i>Calidris fuscicollis</i>). La zona norte del Golfo San Jorge, incluida la caleta Malaspina, ha sido propuesta para la creación de una futura área marina protegida. La información obtenida en este trabajo contribuirá para generar pautas de manejo eficientes para la conservación de éste y otros humedales marinos patagónicos.We studied the diversity and abundance of waterbirds using the intertidals and shallow waters of Malaspina inlet, San Jorge Gulf, Chubut, by means of weekly counts during the spring of 2000. We selected seven survey stations along the coastline of the inlet, representing the habitat heterogeneity of the whole wetland. The waterbird assemblage showed a total of 31 species and exhibited high species diversity, with a core of dominant species and several others that showed low abundance. The composition of the assemblage varied throughout the study, mainly due to the decrease in the number of Kelp Gull (Larus dominacus) and the increase in numbers of the migratory White-rumped Sandpiper (Calidris fuscicollis). The northern sector of San Jorge Gulf, including the Malaspina inlet, has been included in a proposal for a new marine protected area. The information obtained in this study will contribute to the development of management guidelines aimed at the conservation of this and other marine wetlands of Patagonia

Cormorants of the patagonian coast: population status, ecology and conservation

lo largo de la costa de Argentina nidifican cinco especies de cormoranes: el Cormorán Imperial (<i>Phalacrocorax atriceps</i>), el Cormorán Cuello Negro (<i>Phalacrocorax magellanicus</i>), el Cormorán Gris (<i>Phalacrocorax gaimardi</i>), el Biguá (<i>Phalacrocorax olivaceus</i>) y el Guanay (<i>Phalacrocorax bougainvillii</i>). En este trabajo se resume el estado del conocimiento actual, incluyendo información inédita, sobre los principales aspectos de la biología, la ecología, la abundancia y la distribución de las poblaciones de cormoranes en la costa argentina. Además, se presenta un análisis sobre los efectos y conflictos que las principales actividades humanas (transporte de petróleo, explotación guanera, turismo e interacciones con pesquerías) tienen sobre este grupo de aves marinas en la Patagonia argentina. Una serie de recomendaciones sobre estudios futuros para mejorar el manejo y la conservación de estas especies es presentada como conclusión del trabajo.Five species of cormorants breed along the Argentinean coast: Imperial Shag (<i>Phalacrocorax atriceps</i>), Rock Shag (<i>Phalacrocorax magellanicus</i>), Red-legged Shag (<i>Phalacrocorax gaimardi</i>), Neotropic Cormorant (<i>Phalacrocorax olivaceus</i>) and Guanay Shag (<i>Phalacrocorax bougainvillii</i>). This study presents the state of nowadays knowledge, including unpublished information, on different aspects of biology, ecology, abundance and distribution of cormorants’ populations in the Argentinean coast. It also presents an analysis of the effects and conflicts that the main human activities (oil transportation, guano explo.tation, tourism and interaction with fisheries) have on cormorants’ populations in the Argentinean Patagonia. Recommendations for future scientific studies to improve cormorant management and conservation are presented as the final conclusion of this study

Solution of Few-Body Coulomb Problems with Latent Matrices on Multicore Processors

We re-formulate a classical numerical method for the solution of systems of linear equations to tackle problems with latent data, that is, linear systems of dimension that is a priori unknown. This type of systems appears in the solution of few-body Coulomb problems for Atomic Simulation Physics, in the form of multidimensional partial differential equations (PDEs) that require the numerical solution of a sequence of recurrent dense linear systems of growing scale. The large dimension of these systems, with up to several hundred thousands of unknowns, is tackled in our approach via a task-parallel implementation of the solver, using the OmpSs framework.Fil: Biedma, Luis Ariel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Colavecchia, Flavio Dario. Comisión Nacional de Energí­a Atómica. Gerencia del Area Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Balseiro). División Colisiones Atómicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quintana Ortí, Enrique. Universitat Jaume I; EspañaInternational Conference on Computational Science, ICCS 2017ZurichSuizaETH ZürichUniversiteit Van AmsterdamUniversity of TennesseeNanyang Technological Universit

Abundance and diversity of waterbirds in a marine wetland of Golfo San jorge, Argentina

Se estudiaron la diversidad y la abundancia de aves acuáticas que utilizaron los ambientes intermareales y aguas someras de la caleta Malaspina, Golfo San Jorge, Chubut, mediante conteos semanales durante la primavera de 2000. Para esto se ubicaron siete estaciones de muestreo en ambientes intermareales representativos de la heterogeneidad ambiental presente a lo largo de la línea de costa de la caleta. El ensamble estuvo compuesto por 31 especies y mostró una alta diversidad específica de aves acuáticas. La composición del ensamble mostró un núcleo de especies dominantes y muchas especies con abundancias menores, y varió a lo largo del estudio, debido principalmente a la disminución en abundancia de la Gaviota Cocinera (<i>Larus dominicanus</i>) y a la llegada de los primeros pulsos migratorios del Playerito Rabadilla Blanca (<i>Calidris fuscicollis</i>). La zona norte del Golfo San Jorge, incluida la caleta Malaspina, ha sido propuesta para la creación de una futura área marina protegida. La información obtenida en este trabajo contribuirá para generar pautas de manejo eficientes para la conservación de éste y otros humedales marinos patagónicos.We studied the diversity and abundance of waterbirds using the intertidals and shallow waters of Malaspina inlet, San Jorge Gulf, Chubut, by means of weekly counts during the spring of 2000. We selected seven survey stations along the coastline of the inlet, representing the habitat heterogeneity of the whole wetland. The waterbird assemblage showed a total of 31 species and exhibited high species diversity, with a core of dominant species and several others that showed low abundance. The composition of the assemblage varied throughout the study, mainly due to the decrease in the number of Kelp Gull (Larus dominacus) and the increase in numbers of the migratory White-rumped Sandpiper (Calidris fuscicollis). The northern sector of San Jorge Gulf, including the Malaspina inlet, has been included in a proposal for a new marine protected area. The information obtained in this study will contribute to the development of management guidelines aimed at the conservation of this and other marine wetlands of Patagonia

Female-biased stranding in Magellanic penguins

Magellanic penguins (Spheniscus magellanicus) have been reported to become stranded along the coasts of northern Argentina, Uruguay and southern Brazil during the austral winter 1, 2, 3. This location is more than a thousand kilometers distant from their northernmost breeding colony in northern Patagonia. Curiously, females typically outnumber males at stranding sites (approximately three females per male) [2]. To date, no conspicuous sex differences have been reported in their migratory movements [3], although records are lacking during the peak stranding season. Consequently, the reason(s) for the female-biased stranding remain unknown, despite the growing necessity for understanding their behavior outside the breeding season [3]. We recorded at-sea distributions of Magellanic penguins throughout the non-breeding period using animal-borne data loggers and found that females reached more northern areas than males and did not dive as deep during winter (Figure 1). Such sexual differences in spatial domains might be driven by mechanisms related to sexual size dimorphism, such as the avoidance of intraspecific competition for food resources [4], differences in thermal habitat preference [5] or differences in the ability to withstand the northward-flowing ocean circulation [6]. Individual penguins that winter in northern areas are likely to be at greater risk of natural [7] and anthropogenic threats [8], and probably more so in females, as more females than males tend to frequent areas closer to the sites where penguins strand. Our results highlight the importance of understanding the spatial domains of each sex throughout the annual cycle that are associated with different mortality risks.Fil: Yamamoto, Takashi. Nagoya University; JapónFil: Yoda, Ken. Nagoya University; JapónFil: Blanco, Gabriela Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Quintana, Flavio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentin

Colony attendance pattern of Rock Shags (Phalacrocorax magellanicus): an evidence of the use of predictable and low seasonally food sources?

El Cormorán Cuello Negro (Phalacrocorax magellanicus) es una especie endémica de la costa sur de Argentina y Chile. Su patrón de distribución a lo largo de la costa patagónica Argentina, presenta numerosas colonias (143) de tamaño reducido (5–377 parejas). Como parte de un estudio más amplio sobre la ecología trófica de la especie, estudiamos el patrón de presencia en la colonia a lo largo del año en la Reserva de Punta Loma, Chubut, Argentina. Entre Octubre de 2001 y Septiembre de 2003, se realizaron visitas semanales en las que, cada 3 h y durante el período de luz, se determinó la abundancia de las aves mediante conteo directo desde tierra. La abundancia de las aves adultas fue similar en todos los meses del año. La proporción de adultos, juveniles e individuos de menos de un año de edad, varió durante el periodo de estudio. La fluctuación diaria de la abundancia presentó un patrón similar en otoño, invierno, primavera y verano. El mayor número de aves se observó durante el amanecer, disminuyó hacia el mediodía y alcanzó nuevamente máximos hacia el atardecer. Al mediodía, el número de aves fue significativamente menor en otoño que en primavera. El patrón de presencia observado indica que los Cormoranes Cuello Negro permanecen en la colonia todo el año y sugiere que la migración de los adultos hacia áreas alejadas del sitio de nidificación es baja o nula. Los resultados obtenidos soportan la hipótesis del uso de fuentes de alimento predecibles y de baja estacionalidad en las cercanías de la colonia durante todo el año. El bajo contenido energético de las presas capturadas, su baja accesibilidad y/o distribución restringida, podrían ser algunos de los factores responsables del patrón de distribución y abundancia descrito para las colonias del Cormorán Cuello Negro a lo largo de la costa patagónica. Aceptado el 17 de Noviembre de 2005.The Rock Shag (Phalacrocorax magellanicus) is an endemic species of southern Argentina and Chile. In Argentina, the population is distributed along the Patagonian coast in 143 small colonies (5–377 pairs). As part of a broader study of its foraging ecology, we studied the colony attendance pattern of Rock Shags at Punta Loma Reserve, Chubut, Argentina. From October 2001 to September 2003, we visited the colony weekly and counted the birds every 3 h from sunrise to sunset. The abundance of adults was similar through the year, but the proportion of adults, juveniles and birds younger than 1 year, varied along the study period. The daily abundance showed the same pattern during spring, summer, fall and winter. In all cases, the highest abundance was found during the sunrise, decreased at midday, and increased during the sunset. However, the number of birds attending the colony at noon was higher during the spring than during the fall. The colony attendance pattern indicates that cormorants remain at the colony site through the year and suggests that post-breeding migration of adults is rare. Our results support the hypothesis that cormorants exploit a predictable and low seasonally food source located at the proximity of the colony during the whole year. The use of a patchy and/or restricted food source, and the consumption of low energy prey items could be some of the reasons explaining the abundance and distribution pattern described for Rock Shag’s colonies along the Patagonian coast.Fil: Sapoznikow, Alexandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Quintana, Flavio Roberto. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin