Search

Understanding the physiology of stress in wild animals is essential for the conservation of species subject to anthropogenic perturbations. Humboldt penguins (Spheniscus humboldti) are exposed to increasing anthropogenic impacts in their natural habitat. In this species, females are typically smaller and dive less deep than males. In related species, the more limited foraging habitat of females and their reduced resiliency due to their smaller size were associated with higher mortality. We hypothesise that potential sex-specific differences in the foraging behaviour of Humboldt penguins may also relate to differences in their physiological stress. Here, we studied sex-specific foraging and diving behaviours and variations in plasma corticosterone levels and leukocyte profiles of Humboldt penguins during the chick-rearing period in Northern Chile. We report no evidence of sex-related differences in most foraging parameters, except that males dived significantly deeper than females. We found that plasma corticosterone levels and leukocyte profiles showed no significant differences between the sexes. Furthermore, there was no clear relationship between an individual’s foraging behaviour and its plasma corticosterone level or leukocyte profile. In summary, we found no support for sex-related differences in physiological stress levels of Humboldt penguins, and no link between their foraging behaviour and their physiological stress. However, we acknowledge that our sample size is small and that more studies are needed. This study contributes with information on the physiological stress and foraging behaviours of Humboldt penguins in Northern Chile. This information can help to understand context-dependent differences in physiological parameters and foraging behaviours for the species.

Many seabird breeding colonies have recovered from heavy anthropogenic disturbance after conservation actions. The widely distributed red-tailed tropicbird, Phaethon rubricauda, was used as a model species to assess potential anthropogenic impacts on the genetic diversity of breeding colonies in the Pacific Ocean. Cytochrome c oxidase subunit I and control region sequences analyses were conducted across the range of the species in the Pacific Ocean. The study sites were at islands without human-related disturbance (non-impacted islands) and with human-related disturbance (impacted islands). We hypothesized that (i) breeding colonies of the red-tailed tropicbird on impacted islands have lower genetic diversity compared with colonies on non-impacted islands, and (ii) breeding colonies of the red-tailed tropicbird show significant fine and broad-scale genetic structure across the Pacific Ocean. Bayesian skyline analyses were conducted to infer past changes in population sizes. Genetic diversity was similar between impacted and non-impacted islands. There was significant broad-scale genetic structure among colonies separated by over 6,000 km, but a lack of significant fine-scale genetic structure within Australasia and Hawai'i, although a significant level of differentiation was found within Chile with ΦST analyses. Skyline analyses showed that effective population sizes remained relatively constant through time, but experienced either a slight decrease or the end of an expansion event through the last 1,000 years. These changes may be related to the arrival of humans on Pacific islands. Impacted islands may have received immigrants from other relatively close islands, buffering the loss of genetic diversity. However, it is also possible that colonies have retained ancestral variation or that a large effective population size coupled with a long generation time (13 years) has prevented the loss of genetic diversity in human-impacted islands. Future research using higher-resolution markers is needed to resolve the population genetic structure of the red-tailed tropicbird in an ecological time-scale.

La contaminación lumínica afecta a las aves marinas por la atracción hacia fuentes de luz y su posterior caída (fallout) en todo el mundo, siendo los petreles y fardelas las especies más afectadas. La contaminación lumínica está aumentando globalmente y probablemen- te sus efectos sobre estas aves se incrementen en los próximos años. Pese a que existe una evaluación global de esta materia, no existe in- formación detallada para Sudamérica; por esto, el objetivo de este artículo es elaborar un diagnóstico de la situación en Chile, a fin de sugerir un enfoque técnico y político para el país y promover la discusión y acciones al respecto para la región sudamericana. Para ello, se elaboró un diagnóstico de las especies de aves marinas y territorios afectados a través de la consulta directa a investigadores, la revisión sistemática y búsqueda en bases de datos de acceso libre. En Chile, 17 especies de aves marinas son afectadas por la contaminación lumínica, incluyendo seis especies no identificadas previamente en la literatura. El impacto se distribuye principalmente en islas y localidades costeras, con algu- nos casos de localidades a más de 100 km al interior desde la costa. La mayor parte del manejo de este fenómeno en Chile consiste en el rescate y liberación de aves, aunque no hay evidencia del éxito de este enfoque a largo plazo. Medidas como el apagado o recambio de luces son escasas y sólo se han adoptado a pequeña escala y con resultados desconocidos a la fecha. Por ello, una actualización de la política de contaminación lumínica es requerida en Chile y debe considerar la biodiversidad como objeto de protección, el alcance geográfico nacional más allá de las áreas de interés astronómico y debe incluir nuevas tecnologías de iluminación, como luces LED. Finalmente, será de especial importancia la generación de regulaciones más estrictas sobre actividades humanas, incluyendo la iluminación en las cercanías a puntos sensibles, como colonias reproductivas de aves marinas.

SummaryAs island ecosystems are among the most critical breeding habitats for seabirds, their protection should enhance population viability for many species. The Peruvian Diving-petrel Pelecanoides garnotii breeds only in Chile and Perú, is an endangered seabird with historically large populations of over 100,000 breeding pairs, but fewer than 1,000 remained in the 1980s and it became the first endangered seabird of the Humboldt Current System. In Chile, they breed on five islands, three of which are legally protected, but only two have a management plan. Between 2010 and 2014, we evaluated the density of nests, burrow occupancy, and colony patch sizes on the islands to estimate the breeding population. The population trend was assessed by compiling historical data available in the literature and several unpublished technical reports. The current breeding population size in Chile was ∼12,500 breeding pairs (95% CI: 10,613–14,676 pairs) that is ∼34% of the breeding pairs reported for Peru (∼36,450 pairs). Choros Island, the only island with adequate protection, accounted for ∼95% of the total breeding population of the Peruvian Diving-petrel in Chile. Historical population trends showed a significant increase in breeding pairs during recent years on Choros Island. It seems that the adequate legal protection of Choros Island is leading to the recovery of Peruvian Diving-petrels, demonstrating that protection of breeding colonies remains an essential strategy for the conservation of endemic seabirds.

1. While floating near the sea surface plastic debris interacts with a number of external factors, including many different organisms. Seabirds have the most extensive documented history of interactions with plastics, through ingestion, entanglement, and nest construction. 2. In the present study, eight seabird species from the South Pacific Ocean were used as a proxy to determine potential patterns of removal of marine plastic debris, and three hypotheses were tested in relation to their feeding habits and nesting areas. 3. Plastics from abiotic compartments (Chilean continental coast, South Pacific Gyre, and Rapa Nui beaches) and biotic compartments (surface‐feeding seabirds, diving seabirds, and nesting areas) were compared, according to their type, colour, shape, and density. 4. Continental beaches had a relatively wide range of colours and shapes, with many non‐buoyant plastics. Samples from the South Pacific Gyre (SPG) and Rapa Nui (Easter Island) beaches comprised mainly hard, rounded, buoyant, and white/grey plastics. 5. These results indicate that the composition of floating plastics from terrestrial sources changes during transport with oceanic currents, reducing the proportion of prey‐like plastics present in the subtropical gyres. 6. The stomach contents of surface‐feeding and diving seabirds were dominated by hard, white/grey, and round plastic items, similar to plastics from the SPG, suggesting non‐selective (accidental or secondary) ingestion. 7. Nesting areas had a more variable composition of brightly coloured plastics, suggesting a pattern of selective removal of plastics by seabirds, probably from oceanic sources. 8. The present study reveals extensive interactions of seabirds with plastics on a broader scale, which is highly relevant given that the impacts of plastics on seabirds are increasing worldwide, compromising their efficient conservation.

International audience

Background Introduced predators at seabird colonies and parasites may have lethal and/or sub-lethal consequences for bird populations. We assessed the potential sub-lethal negative effects of these stressors in a native seabird listed as vulnerable in its south-eastern pacific distribution. This study was conducted in two red-tailed tropicbird (Phaethon rubricauda) colonies, one located in Rapa Nui Island, which is threatened by the presence of introduced predators, and the other located in Salas & Gómez Island, which has no introduced predators, but birds are infested by ectoparasitic louse flies. Methods The effects on physiological stress traits of both, predation risk on different nest types (protected and exposed) on Rapa Nui, and different levels of louse flies’ parasitic loads on Salas & Gómez were studied. Three variables were analyzed: the heterophil/lymphocyte (H/L) ratio, the transcriptional levels of mRNA HSP70 in blood, and the body condition. These stress indicators and leukocyte counts were compared between colonies. Results No significant differences were found in any stress indicator between different nest types within Rapa Nui, showing that the effect of predator’s presence was the same for adults nesting in both, protected and exposed nests. No significant correlation was found between louse flies’ parasitic loads and any stress indicators in the birds of Salas & Gómez. Also, there was no difference in any stress indicator between islands. However, a significant opposite trend between islands was found in the eosinophil, lymphocyte, and monocyte counts when related to body condition. Conclusions We found a lack of significant differentiation in all the stress level indicators assessed within and between islands. The presence of louse flies in Salas & Gómez vs. the absence of this parasite at Rapa Nui may be the cause for the significant difference in the trend of eosinophil, lymphocyte and monocyte counts between the islands. However, further studies are necessary to elucidate the reason for this difference and to better investigate the lethal effects of introduced predators on the Rapa Nui colony to evaluate appropriate conservation measures for this native seabird.

The South Pacific Gyre has the most hyper-oligotrophic waters in the world and is considered the largest “oceanic desert.” Rapa Nui (Easter Island), located within the South Pacific Gyre, is a breeding ground for masked boobies (Sula dactylatra), which are seabirds with a foraging range that effectively confines them within the gyre. The foraging ecology of this species in the gyre was examined by attaching GPS and time-depth devices to chick-rearing adult birds (9 and 14 birds in 2016 and 2017, respectively) and by collecting regurgitates (18 and 15 samples in 2016 and 2017, respectively). In addition, the birds’ foraging ecology between years was compared. Masked boobies traveled in various directions, dived at unspecific locations, and explored areas

· We report the breeding attempt of South American Terns (Sterna hirundinacea) on three boats in Coquimbo, northern Chile. The first breeding attempt was reported in winter 2011 where at least one chick fledged. From April to June 2015, all nests on the boats were monitored. We recorded eggs and chicks during May and early June. However, towards the end of June, no eggs or chicks were recorded in the nests, and a Chimango Caracara (Phalcoboenus chimango) was observed preying on chicks in one nest. In April and May 2017, breeding attempts on boats were also monitored and nests with eggs and one chick were recorded. However, at the end of May all nests were empty. This unusual nesting site for South American Terns is apparently regularly used in the area despite its virtually null breeding success. Resumen · Reproducción del Gaviotín Sudamericano (Sterna hirundinacea) en botes anclados en Coquimbo, norte de Chile Reportamos el intento de reproducción del Gaviotín Sudamericano (Sterna hirundinacea) sobre tres botes en Coquimbo, norte de Chile. Un primer intento de reproducción para esta zona se registró en invierno de 2011, donde al menos un pollo dejó un nido como volantón. Entre Abril y Junio de 2015 monitoreamos los nidos en los botes de manera más intensiva. Registramos huevos y pollos durante Mayo y principios de Junio. Sin embargo, a finales de Junio, no registramos huevos en los nidos y observamos un Tiuque (Phalcoboenus chimango) depredar sobre los pollos. En Abril y Mayo de 2017, monitoreamos otros intentos de reproducción y registramos un pollo y nidos con huevos. Sin embargo, a finales de Mayo, esos nidos estaban vacíos. Este inusual sitio de nidificación parece ser utilizado de forma recurrente por el Gaviotín Sudamericano, a pesar del aparente casi nulo éxito reproductivo.

The invasive Argentine Ant, Linepithema humile, is known to prey on land bird chicks, but there are few reports of the ants’ impacts on breeding seabirds. We conducted a manipulative study ...

Penguins are the most threatened group of seabirds after albatrosses. Although penguins are regularly captured in fishing gear, the threat to penguins as a group has not yet been assessed. We reviewed both published and grey literature to identify the fishing gear types that penguins are most frequently recorded in, the most impacted species and, for these susceptible species, the relative importance of bycatch compared to other threats. While quantitative estimates of overall bycatch levels are difficult to obtain, this review highlights that, of the worldís 18 species of penguins, 14 have been recorded as bycatch in fishing gear and that gillnets, and to a lesser extent trawls, are the gear types that pose the greatest threats to penguins. Bycatch is currently of greatest concern for yellow-eyed Megadyptes antipodes (Endangered), Humboldt Spheniscus humboldti (Vulnerable) and Magellanic Spheniscus magellanicus penguins (Near Threatened). Penguins face many threats; reducing bycatch mortality in fishing gear will greatly enhance the resilience of penguin populations to threats from habitat loss and climate change that are more difficult to address in the short term. Additional data are required to quantify the true extent of penguin bycatch, particularly for the most susceptible species. In the meantime, it is crucially important to manage the fisheries operating within known penguin foraging areas to reduce the risks to this already threatened group of seabirds.

Abstract Sexual segregation in foraging occurs in some species and populations of boobies (Sulidae), but it is not a general pattern. Sexual segregation in foraging may occur to avoid competition for food, and this competition may intensify during specific stages of breeding. We examined sexual segregation in foraging in relation to breeding stage in masked boobies Sula dactylatra at Rapa Nui by tracking simultaneously incubating and chick-rearing birds using GPS recorders (n = 18) and collected a total of 11 regurgitate samples. Stable isotope analyses (δ13C and δ15N) of whole blood samples were carried out in 20 birds. There were no differences in foraging trip parameters or diet between females and males. Both sexes traveled farther and for longer while incubating than while rearing chicks. Isotopic niches (δ13C and δ15N) overlapped to some degree among all groups at all times, but the lowest overlap between sexes occurred during incubation. While preying on ephemerally distributed flying fish, vertical or horizontal competition avoidance may be almost impossible, and thus females and males share their foraging grounds. Since birds were tracked simultaneously, shorter foraging trips of chick-rearing birds must be an effect of the constraints of provisioning the chick. Differences observed in δ15N and δ13C values between sexes may be caused by subtle differences in their foraging behaviors, or by differences in physiology linked to breeding. Our findings suggest that local oceanography and its inherent food distribution are determinants for sexual segregation in foraging patterns in masked boobies and possibly also other booby species. Significance statement In some animals, females and males forage on different areas or prey on different species to avoid competition for food resources. In boobies (Sula sp.), some studies show evidence of sexual segregation in foraging and others do not. Here, we tested if sexual segregation in foraging occurred in masked boobies on the Pacific island of Rapa Nui by studying simultaneously incubating and chick-rearing birds. We found no evidence of sexual segregation on foraging behavior or diet. We discuss that the difference between this and other studies in boobies may be an effect of the local prey availability. When the prey community is more diverse and heterogeneously distributed, each sex may access different resources and thus sexual foraging segregation will occur. In contrast, in areas like Rapa Nui where prey resources are distributed ephemerally, sexual segregation in foraging will not be useful and is thus less likely to occur.

Background Introduced predators at seabird colonies and parasites may have lethal and/or sub-lethal consequences for bird populations. We assessed the potential sub-lethal negative effects of these stressors in a native seabird listed as vulnerable in its south-eastern pacific distribution. This study was conducted in two red-tailed tropicbird (Phaethon rubricauda) colonies, one located in Rapa Nui Island, which is threatened by the presence of introduced predators, and the other located in Salas & Gómez Island, which has no introduced predators, but birds are infested by ectoparasitic louse flies. Methods The effects on physiological stress traits of both, predation risk on different nest types (protected and exposed) on Rapa Nui, and different levels of louse flies’ parasitic loads on Salas & Gómez were studied. Three variables were analyzed: the heterophil/lymphocyte (H/L) ratio, the transcriptional levels of mRNA HSP70 in blood, and the body condition. These stress indicators and leukocyte counts were compared between colonies. Results No significant differences were found in any stress indicator between different nest types within Rapa Nui, showing that the effect of predator’s presence was the same for adults nesting in both, protected and exposed nests. No significant correlation was found between louse flies’ parasitic loads and any stress indicators in the birds of Salas & Gómez. Also, there was no difference in any stress indicator between islands. However, a significant opposite trend between islands was found in the eosinophil, lymphocyte, and monocyte counts when related to body condition. Conclusions We found a lack of significant differentiation in all the stress level indicators assessed within and between islands. The presence of louse flies in Salas & Gómez vs. the absence of this parasite at Rapa Nui may be the cause for the significant difference in the trend of eosinophil, lymphocyte and monocyte counts between the islands. However, further studies are necessary to elucidate the reason for this difference and to better investigate the lethal effects of introduced predators on the Rapa Nui colony to evaluate appropriate conservation measures for this native seabird.

The Chilean coast holds a high seabird diversity and also extensive fisheries that interact with birds producing bycatch. We used data on beached seabirds reported by news media to depict spatial and temporal patterns of fishery-related seabird mortality and correlated these data with the spatial and temporal fishing effort of the three main purse-seine fleets operating in south-central Chile (33 to 40°S). Between 2005 and 2019 we detected 97 mortality events reporting >19,000 beached seabirds attributed to bycatch. Mortality was recorded between 18 and 53° S (~3800 km of coastline), affecting 16 seabird species, with 90% concentrated between 33 and 40°S (800 km), exactly where purse-seine fleets operate. Sooty shearwater (Ardenna grisea) comprised 70% of all dead birds recorded. Magellanic penguins (Spheniscus magellanicus) and guanay cormorants (Phalacrocorax boungainvillii) were also affected. Mortality events of Sooty shearwaters was highest (P

In South America, Kelp Gulls (Larus dominicanus) breed from Chilean Tierra del Fuego north to Rio de Janeiro, Brazil, on the Atlantic coast and to Piura, Peru, on the Pacific coast. This review presents the first synthesis of information on the distribution and size of Kelp Gull colonies at the country level in coastal environments of Uruguay, Chile and Peru; provides an update on the breeding situation of the species in Brazil and Argentina; and allows the first evaluation of the overall coastal breeding population in South America. The breeding population in South America is now estimated to number at least 160,000 pairs. The largest population (at least 106,000 breeding pairs) is found in Argentina. Colonies of more than 1,000 pairs are uncommon. Population trends differed among coastal sectors, and important increases in numbers and formation of new colonies were only observed in Argentina. Available information suggests that predictable and abundant anthropogenic food subsidies, such as fishery discards and urban waste, are key factors contributing to the population growth in some coastal sectors. There is no strong evidence that Kelp Gulls are currently expanding their breeding range. However, given the population expansion in some areas and the potential conflicts with humans, ongoing monitoring efforts and population evaluations are necessary as they will provide the information required to support management decisions.

The Gray Gull (Leucophaeus modestus) has the unique habit among gulls of nesting in the interior Atacama Desert, up to 100 km from the coast. During the 2014–2015 austral breeding season, two breeding colonies were recorded on the coast within 90 m of the shoreline in the Antofagasta Region, northern Chile. The new colonies ranged in size from 40 (Playa Grande) to 150 (Playa Brava) nests. Egg laying was synchronous in both colonies and most likely occurred in late November 2014, coinciding with egg laying in desert colonies. The colony at Playa Brava was successful, but the one at Playa Grande was deserted due to feral dog (Canis familiaris) attacks. The habitat used by Gray Gulls resembled that reported for desert colonies, with flat plains covered with small rocks, which provide protection to chicks from intense solar radiation. This unusual coastal nesting behavior could result in the modification of certain life history and behavioral traits in the Gray Gull (e.g., chick growth rates, energy...

In less than one century, the once-abundant Peruvian diving petrel has become the first endangered seabird of the Humboldt Current System (HCS). This small endemic petrel of the South American Pacific coast is now an important indicator of ongoing habitat loss and of the success of local conservation policies in the HCS - an ecoregion designated as a priority for the conservation of global biodiversity. Yet so far, poorly understood life history traits such as philopatry or dispersal ability may strongly influence the species’ response to ecosystem changes, but also our capacity to assess and interpret this response. To address this question, we explore the range-wide population structure of the Peruvian diving petrel, and show that this small seabird exhibits extreme philopatric behavior at the island level. Mitochondrial DNA sequences and genome-wide SNP data reveal significant isolation and low migration at very short distances, and provide strong evidence for questioning the alleged recovery in the Peruvian and Chilean populations of this species. Importantly, the full demographic independence between colonies makes local population rescue through migration unlikely. As a consequence, the Peruvian diving petrel appears to be particularly vulnerable to ongoing anthropogenic pressure. By excluding immigration as a major factor of demographic recovery, our results highlight the unambiguously positive impact of local conservation measures on breeding populations; yet at the same time they also cast doubt on alleged range-wide positive population trends. Overall, the protection of independent breeding colonies, and not only of the species as a whole, remains a major element in the conservation strategy for endemic seabirds. Finally, we underline the importance of considering the philopatric behavior and demographic independence of breeding populations, even at very fine spatial scales, in spatial planning for marine coastal areas.

Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue.

Oceanic marine protected areas (MPAs) that are close to the litter accumulation zones in the subtropical gyres receive large amounts of plastic litter, both as micro- and as macroplastics. The macro-litter accumulating on the islands in the Easter Island Ecoregion (Rapa Nui and Salas y Gomez) can be traced back to the high seas industrial fishery operating in the South Pacific. Seabirds nesting in the MPAs in the South Pacific are affected by both microplastic ingestion and macroplastic in their nests, but there was no evidence of entangled birds. Conservation of seabirds (and other species) in these oceanic MPAs requires efficient measures to reduce plastic contamination in the ocean. Observations made in the South Pacific coincide with those from other oceanic MPAs, calling for global actions.

The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under genetic drift. High gene flow among populations, that can be constant or pulses of migration in a short period, may also decrease power of algorithms to detect genetic structure. Penguin species usually have large population sizes, high migratory ability but philopatric behavior, and recent investigations debate the existence of subtle population structure for some species not detected before. Previous study on Humboldt penguins found lack of population genetic structure for colonies of Punta San Juan and from South Chile. Here, we used mtDNA and nuclear markers (10 microsatellites and RAG1 intron) to evaluate population structure for 11 main breeding colonies of Humboldt penguins, covering the whole spatial distribution of this species. Although mtDNA failed to detect population structure, microsatellite loci and nuclear intron detected population structure along its latitudinal distribution. Microsatellite showed significant Rst values between most of pairwise locations (44 of 56 locations, Rst = 0.003 to 0.081) and 86% of individuals were assigned to their sampled colony, suggesting philopatry. STRUCTURE detected three main genetic clusters according to geographical locations: i) Peru; ii) North of Chile; and iii) Central-South of Chile. The Humboldt penguin shows signal population expansion after the Last Glacial Maximum (LGM), suggesting that the genetic structure of the species is a result of population dynamics and foraging colder water upwelling that favor gene flow and phylopatric rate. Our findings thus highlight that variable markers and wide sampling along the species distribution are crucial to better understand genetic population structure in animals with high dispersal ability.

El monitoreo de las aves varadas en las playas puede proporcionar información sobre sus causas de muerte, tales como la captura incidental en actividades de pesca o derrames de petróleo. Durante un año fue monitoreada mensualmente la Bahía de Coquimbo, norte de Chile para cuantificar el número de aves marinas varadas. Se encontraron 395 aves marinas muertas de las cuales 382 fueron identificadas y agrupadas en 21 especies. Las especies más abundantes fueron los piqueros con 115 individuos (30%), el cormorán guanay con 83 individuos (22%) y la gaviota dominicana con 65 individuos (17%). Las especies más abundantes y frecuentes fueron las que anidan en el Sistema Costero de Coquimbo. La mortalidad afecta principalmente a las aves marinas que se alimentan de la anchoveta, que es el principal recurso objetivo de la pesca con redes de cerco. Se sugiere que la mortalidad incidental causada por la pesca es crónica y relativamente constante durante el año. Se requiere un programa de monitoreo a largo plazo para mejorar la estimación de la mortalidad y los factores que influyen en la interacción de las aves marinas con las artes de pesca.

The Antarctic fur seal, Arctocephalus gazella, has a wide distribution range and breeds primarily in subantarctic and Antarctic locations of the Southern Ocean. We report the first record of this species in northern Chile in August, 2014. Although no external trauma was observed, the seal was presumed to be sick because it appeared to be underweight. This sighting is the northernmost record of this species on islands and the continental coastal areas of the southeastern South Pacific.

In both sedimentary and rocky coastal habitats, epibenthic mytilid mussels use byssal threads for attachment to the substratum and to form beds with high densities of individuals. Number and attachment strength of byssal threads can be adjusted according to external factors such as hydrodynamic forces or predators, but it is unknown whether mytilid mussels distinguish between substrata of different quality for byssus attachment in different habitat types. In field studies, we examined the attachment strength of the mussel Perumytilus purpuratus growing on Pacific hard- and soft-bottom shores in Chile and of the blue mussel Mytilus edulis from an Atlantic rocky shore in France and a sedimentary shore in the North Sea (Germany), respectively. In additional laboratory experiments, we studied mussel substratum selectivity of both bivalve species from soft and hard bottoms by offering living versus dead, barnacle-fouled vs. unfouled, and firmly attached vs. loose conspecifics. In the field, attachment strength of P. purpuratus on hard bottoms was substantially higher than on soft bottoms even though mussels produced more byssus in the latter habitat. In contrast, blue mussels M. edulis showed only a slightly reduced attachment strength on soft compared to hard bottoms. In the soft-bottom habitat, fouled individuals from the edge of a blue mussel bed were especially strongly attached. In the byssus attachment behavior experiments, P. purpuratus from both habitats showed a significant preference for living conspecifics and those from soft bottoms preferred firmly attached conspecifics. Blue mussels had no preference for particular conspecifics except those from soft-bottom habitats, which preferred fouled over clean mussels. In general, in the choice experiments hard-bottom M. edulis produced more byssus. Our results confirmed that mytilid mussels may show active substratum choice for byssus attachment, which depends on mussel species and habitat type. The results suggest that mussels are adapted to a particular habitat type, with P. purpuratus showing lower adaptation to soft-bottom areas while M. edulis shows successful strategies for both environments.

The bull kelp Durvillaea antarctica is a common floating alga in the southern hemisphere, but despite the ecological and biogeographic importance of kelp rafts, little is known about the responses of detached kelps to the conditions at the sea surface. The morphological, physiological and reproductive performances of D. antarctica rafts in the Coastal System of Coquimbo, Chile (CSC, ~30°S), were examined during winter and summer of two successive years (2010/11 and 2011/12). Epibionts (Lepas spp.) that only attach to floating objects were used as indicator for the floating time of kelp rafts. Photosynthetic efficiency and reproductive maturity of both benthic and floating algae varied seasonally, with a stronger decrease in summer than in winter. Blade size (measured as weight proportion of kelp individuals), phlorotannin concentrations and antioxidant activities were lower in floating than in benthic algae. Environmental conditions and floating time affected the blade tissues, with stronger negative effects during summer. These results confirm that floating persistence of D. antarctica in the CSC is suppressed during the summer months, which indicates that the dispersal potential of this (and other) floating algae varies seasonally.

The evolutionary and adaptive potential of populations or species facing an emerginginfectious disease depends on their genetic diversity in genes, such as the major histocompatibilitycomplex (MHC). In birds, MHC class I deals predominantly with intracellularinfections (e.g., viruses) and MHC class II with extracellular infections (e.g.,bacteria). Therefore, patterns of MHC I and II diversity may differ between species andacross populations of species depending on the relative effect of local and global environmentalselective pressures, genetic drift, and gene flow. We hypothesize thathigh gene flow among populations of Humboldt and Magellanic penguins limits localadaptation in MHC I and MHC II, and signatures of selection differ between markers,locations, and species. We evaluated the MHC I and II diversity using 454 next-generationsequencing of 100 Humboldt and 75 Magellanic penguins from seven differentbreeding colonies. Higher genetic diversity was observed in MHC I than MHCII for both species, explained by more than one MHC I loci identified. Large populationsizes, high gene flow, and/or similar selection pressures maintain diversity but limitlocal adaptation in MHC I. A pattern of isolation by distance was observed for MHC IIfor Humboldt penguin suggesting local adaptation, mainly on the northernmost studiedlocality. Furthermore, trans-speciesalleles were found due to a recent speciationfor the genus or convergent evolution. High MHC I and MHC II gene diversity describedis extremely advantageous for the long-termsurvival of the species. Fil: Sallaberry Pincheira, Nicole. Pontificia Universidad Católica de Chile; Chile. Universidad Andrés Bello; Chile Fil: González Acuña, Daniel. Universidad de Concepción; Chile Fil: Padilla, Pamela Solange. Pontificia Universidad Católica de Chile; Chile Fil: Dantas, Gisele P. M.. Pontificia Universidade Catolica de Minas Gerais.; Brasil Fil: Luna Jorquera, Guillermo. Universidad Católica del Norte; Chile Fil: Frere, Esteban. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Valdés Velásquez, Armando. Universidad Peruana Cayetano Heredia; Perú Fil: Vianna, Juliana A.. Pontificia Universidad Católica de Chile; Chile

Rats (Rattus spp.) are among the most successful alien predators brought to islands by humans and have had devastating impacts on numerous seabird populations, but studies demonstrating rates of consumption and ecological impacts on penguins are scarce and mostly based on anec- dotal evidence. We investigated the effects of rat predation on Humboldt Penguins (Spheniscus humboldti) by simulat- ing unattended clutches with domestic Chicken eggs. Experiments were independently set at two Humboldt Pen- guin colonies in north (Pajaros Island, 29S) and central Chile (Algarrobo Island, 33S). At both colonies, eggs were primarily predated by rats (Rattus rattus = 70.8 % at Paja- ros and Rattus norvegicus = 52.6 % at Algarrobo), and secondarily by Kelp Gulls (Larus dominicanus = 9.7 % at Pajaros and 15.8 % at Algarrobo). Significantly more eggs were predated at night. At both colonies, rates of rat and gull predation were highest within the first 12 h. Our study con- stitutes the first quantification of rats as important alien predators at Humboldt Penguin colonies. We suggest that rat presence at Humboldt Penguin colonies coupled with events that can cause temporary nest abandonment, such as human perturbation and El Nino events, may impact on the species' breeding success. Eradication of rats is suggested to improve the nesting habitat of this and other threatened and endemic seabird species in the region.

A wide diversity of organisms is dispersed on abiotic floating substrata, but little is known about the succession of fouling communities on these items. The main abiotic floating items found in the oceans (volcanic pumice, plastics, and Styrofoam) differ in 3 principal characteristics, namely surface rugosity, buoyancy, and floating behaviour, confirmed herein by light and electron microscopy (SEM), measurements of buoyancy, and laboratory tests to determine floating stability. In order to examine how these properties affect colonization and com munity succession on these substrata, 3 experiments were conducted in the field for 14 wk: (1) substrata were permanently submerged to determine if colonization depends on substratum surface (‘Rings’ experiment); (2) substrata were tethered at the sea surface to examine the importance of buoyancy (‘Lines’ experiment); and (3) substrata were caged to test the role of their floating behaviour (‘Cages’ experiment). The most common colo nizers in all 3 experiments were diatoms, Ulvales, and clonal ascidians from the genus Diplosoma. Surface rugosity of the substrata had only minor effects on the taxonomic richness of the developing communities. Buoyancy caused some differences in taxon cover, but taxon richness was similar on all 3 substrata. Finally, the floating behaviour at the sea surface had a strong influence on the communities developing on the floating substrata. Plastics (fewest changes in position) presented a higher richness and cover of taxa, while Styrofoam (most positional changes) harboured very few taxa. We conclude that colonization and succession on floating substrata is strongly influenced by positional changes, while surface rugosity and buoyancy appear important only during initial stages of community succession. Dispersal of organisms across the oceans is brought about by dense aggregations of pumice (left), which may appear sporadically after submarine volcanic eruptions, and by ubiquitous accumulations of anthropogenic debris (right). Photos: A. van den Broek, S. Bryan (left); M. Thiel (right) OPEN ACCESS

We analyzed Cu and Cd liver concentration in adults and fledglings of Kelp gull from an urban (Coquimbo city) and a wild (Pájaros Islet) colony. Cu concentration was 15.57 ± 0.079 µg g-1 dry weight for adults and fledglings of both colonies. Adults Cd concentration from both colonies was 9.72 ± 0.110 µg g-1 dw, being 194% of the level considered toxic but in the range for seabirds. In the urban fledglings Cd was below the detection level. Wild fledgling showed higher concentration of 1.54 ± 0.064 µg g-1 dw which probably reflects a biomagnification process, because parents kleptoparasite and consume eggs and chicks of other seabirds.

Marine ecosystems and their inhabitants are increasingly under threat from climate change, competition with humans for resources, and pollution. Species that are endemic to particular currents or regions of the world’s oceans have the potential to be at higher risk due to localized overfishing, pollution, or locally severe impacts of climate change such as more intense, or longer, El Nino Southern Oscillation events. Understanding patterns of population differentiation in endemic marine organisms may be particularly important for their conservation and persistence. Peruvian Boobies (Sula variegata) are endemic to the Humboldt Current upwelling system and have experienced population fluctuations throughout their evolutionary history due to both dramatic reduction of food supplies, and anthropogenic influence over the last ~150 years. Recent research on other members of the Sulidae indicates that populations of these primarily tropical seabirds show a high degree of genetic differentiation; however, the sister species of the Peruvian Booby, the Blue-footed Booby (S. nebouxii), exhibits only weak range-wide population genetic structure. We characterized population genetic differentiation and diversity in 153 Peruvian Boobies using sequence variation of 540 base pairs of the mitochondrial control region and seven microsatellite loci. Although we found evidence of panmixia, a signature of isolation by distance appears to exist between the five sampled colonies. We also found unexpectedly high genetic diversity given this species’ recent population decline. Our results are similar to those for the Humboldt Penguin (Spheniscus humboldti), another endemic of the Humboldt Current upwelling system.

Anthropogenic marine debris (AMD) is an ubiquitous problem, which has motivated public participation in activities such as beach surveys and clean-up campaigns. While it is known that beaches in the SE Pacific are also affected by this problem, the quantities and types of AMD remain largely unknown. In the context of an outreach project, volunteers (approximately 1500 high-school students) participated in a nation-wide survey of AMD on 43 beaches distributed randomly along the entire Chilean coast (18 degrees S to 53 degrees S). The mean density of AMD was 1.8 items m(-2) and the major types were plastics, cigarette butts and glass. Densities in central Chile were lower than in northern and southern Chile, which could be due to different attitudes of beach users or to intense beach cleaning in central regions. We suggest that public participation in surveys and cleaning activities will raise awareness and thereby contribute to an improvement of the situation.

Villablanca, R., Luna-Jorquera, G., Marín, V. H., Garthe, S., and Simeone, A. 2007. How does a generalist seabird species use its marine habitat? The case of the kelp gull in a coastal upwelling area of the Humboldt Current. – ICES Journal of Marine Science, 64: 1348–1355. The distribution of kelp gulls (Larus dominicanus) was studied by ship-based transect counts in the SE Pacific Ocean off Chile, South America. Some 96–98% of the kelp gulls were in a band less than 20 km from the coast, mainly near the breeding colony on Pájaros Island and the City of Coquimbo. Abundance did not change significantly among years, but was influenced significantly by distance to land. Principal component analysis yielded two components that jointly explain 53% of the standardized variance. The first (explaining 36% of the variance) includes distance to the nearest coast and water depth, the second (17%) associates with the presence of fishing vessels. The results suggest that the stability of the summer distribution of kelp gulls is generated by the large and semi-permanent offer of food at fish markets and city sewage works, as well as the location of the breeding colonies. Further analysis on other temporal scales (seasonal, decadal) associated with reproductive or non-reproductive changes within the population and/or ENSO cycles will be necessary to confirm the multiscale stability of the pattern described.

Over the last decade the Humboldt penguin, Spheniscus humboldti, has become a focus for ecotourism. Current management applies visitor guidelines similar to those developed for Magellanic penguins, Spheniscus magellanicus. However, unlike these, Humboldt penguins are extremely sensitive to human presence. Breeding success was significantly reduced at frequently visited sites. Heart rate telemetry during disturbance experiments revealed that Humboldt penguins respond more strongly to human presence than do any other penguin species thus far studied. A person passing an incubating penguin at 150 m distance already provoked a significant heart rate response. Recovery times were up to half an hour after direct human approach, causing increased energy expenditure without any overt behavioural reaction. Being extraordinary sensitive to human activity with little habituation potential the Humboldt penguin proves to be a difficult focal species for ecotourism. For sustainable ecotourism visitors are required to stay out of sight of Humboldt penguin breeding and moulting areas. Management guidelines need to acknowledge that even closely related species may react very differently towards human presence.

The feeding ecology of the Kelp Gull (Larus dominicanus) was studied during the 2002-03 breeding season at Coquimbo, northern Chile. Food composition was studied by analyzing pellets regurgitated by Kelp Gulls living in different habitats. Birds breeding or resting near fishing ports used these as their main feeding grounds. Birds breeding on offshore islands fed mainly on intertidal organisms and olives. A comparison between the food of breeders and non-breeding birds during the breeding season showed a difference in diet composition of breeders, who fed more on fish of high energy density while non-breeding birds continued feeding on a wide range of organisms and waste. Observations in a fishing harbor and at sea demonstrated that fisheries waste was an important food source for the birds. The inshore distribution at sea was related to the location of fishing ports and breeding colonies.

While Isla Chanaral (29°02’S) in Chile has long been recognized as one of the most important breeding islands for the Humboldt Penguin, the reported numbers of birds there never exceeded 3,500 breeding individuals in the last two decades. However, in 2002, a one-day survey found considerably more penguins present on Isla Chanaral, which exceed the world population estimate for the species (3,300-12,000 birds). Between 9 and 14 February 2003 we conducted a census of the Humboldt Penguin on Isla Chanaral. Two different survey methods were combined to assess the number of penguins. Terrestrial or surface counts were used to survey penguins on open plains or beaches. Small area surveys of randomly established quadrats were conducted to assess the density of penguins in nests and the total number of nest sites. Results from small area surveys were extrapolated using surface size ratios of counting quadrats vs. entire nesting sectors. We determined that approximately 22,000 adult Humboldt Penguins, 3,6...

We examined the thermoregulatory behaviour (TRB) of roosting Humboldt penguins (Spheniscus humboldti) in north central Chile during summer and winter, when ambient temperatures (Ta) are most extreme. Each body posture was considered to represent a particular TRB, which was ranked in a sequence that reflected different degrees of thermal load and was assigned an arbitrary thermoregulatory score. During summer, birds exhibited eight different TRBs, mainly oriented to heat dissipation, and experienced a wide range of Ta (from 14 to 31°C), occasionally above their thermoneutral zone (TNZ, from 2 to 30°C), this being evident by observations of extreme thermoregulatory responses such as panting. In winter, birds exhibited only three TRBs, mainly oriented to heat retention, and experienced a smaller range of Ta (from 11 to 18°C), always within the TNZ, even at night. The components of behavioural responses increased directly with the heat load which explains the broader behavioural repertoire observed in summer. Since penguins are primarily adapted in morphology and physiology to cope with low water temperatures, our results suggest that behavioural thermoregulation may be important in the maintenance of the thermal balance in Humboldt penguins while on land.

SUMMARYHumboldt penguins Spheniscus humboldti in captivity and free-living Magellanic penguins S. magellanicus were fitted with loggers to determine beak angles during breathing. The Humboldt penguins were also fitted with masks for determining rates of air flow during breathing. During periods of higher gas exchange requirement, Humboldt penguins opened their beaks during inspiration, where tidal volume was linearly correlated with both change in beak angle and maximum beak angle, closed them slightly during the final stages of inspiration and finally closed them during expiration. Substantial differences were apparent between individuals. Contrary to the condition proposed for most birds, our data suggest that expiration is passive during periods of high respiratory tidal volumes, and that the increased resistance of the respiratory pathway serves to slow air flow so as to maximize gas exchange in the lungs. During foraging, Magellanic penguins at the surface between dives showed similar breathing patterns but maximum beak angles were much higher and breath cycle time shorter, as would be expected for animals attempting to maximize gas exchange. Both maximum beak angle per breath and breath frequency changed systematically over the surface pause; both were initially high, then decreased to a low before rising again to a maximum just before diving. Based on known changes in tidal volume with beak angle derived from Humboldt penguins, a simple model is proposed to examine rates of gas exchange over the surface pause. This indicates that the observed patterns do not maximize the rate of transfer of oxygen over the whole of the surface pause but are rather concerned with an initial rapid accumulation of oxygen in the tissues followed by effective carbon dioxide release.

Anthropogenic impact has been heavy in remote oceanic islands, including the introduction of alien species, having negative effects on native seabirds. The isolated and subtropical Rapa Nui (Easter...

Avian malaria is a disease caused by species of the genera Haemoproteus, Leucocytozoon, and Plasmodium. It affects hundreds of bird species, causing varied clinical signs depending on the susceptibility of the host species. Although high mortality has been reported in captive penguins, limited epidemiological studies have been conducted in wild colonies, and isolated records of avian malaria have been reported mostly from individuals referred to rehabilitation centers. For this epidemiological study, we obtained blood samples from 501 adult Humboldt and 360 adult Magellanic penguins from 13 colonies throughout South America. To identify malaria parasitaemia, we amplified the mtDNA cytochrome b for all three parasite genera. Avian malaria was absent in most of the analyzed colonies, with exception of the Punta San Juan Humboldt penguin colony, in Peru, where we detected at least two new Haemoproteus lineages in three positive samples, resulting in a prevalence of 0.6% for the species. The low prevalence of avian malaria detected in wild penguins could be due to two possible causes: A low incidence, with high morbidity and mortality in wild penguins or alternatively, penguins sampled in the chronic stage of the disease (during which parasitaemia in peripheral blood samples is unlikely) would be detected as false negatives. Fil: Sallaberry Pincheira, Nicole. Universidad Católica de Chile; Chile. Pontificia Universidad Católica de Chile; Chile. Universidad Andrés Bello; Chile Fil: Gonzalez Acuña, Daniel. Universidad de Concepción; Chile Fil: Herrera Tello, Yertiza. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile Fil: Dantas, Gisele P. M.. Pontificia Universidade Catolica de Minas Gerais; Fil: Luna Jorquera, Guillermo. Universidad Catolica del Norte; Chile Fil: Frere, Esteban. Universidad Nacional de la Patagonia Austral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Valdés Velasquez, Armando. Universidad Peruana Cayetano Heredia; Perú Fil: Simeone, Alejandro. Universidad Andrés Bello; Chile Fil: Vianna, Juliana A.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile