Avian orthoavulavirus 1 (Newcastle Disease virus) antibodies in five penguin species, Antarctic peninsula and Southern Patagonia.

Avian orthoavulavirus 1 (AOaV-1) causes Newcastle disease, one of the most important and contagious infections in poultry, where migratory birds can play a key role as a reservoir. Seven hundred and seven serum samples were collected from five penguin species (King, Magellanic, Gentoo, Chinstrap and Adelie penguins) in the Antarctic and Sub-Antarctic zones. Using a competitive ELISA to detect antibodies against AOaV-1, we identified positive individuals in all penguin species. The Magellanic penguin showed the highest seropositivity rate (30.3%), suggesting it could be a natural reservoir of this virus. At the Antarctic zones, Chinstrap penguin showed the highest occurrence (7.5%). Interesting, positive sera was only obtained in Sub-Antarctic and Northern zones at the Antarctic peninsula, no seroreactivity was observed in Southern locations. Further studies are needed to establish the role of these penguin species in the epidemiology of the AOaV-1 and determine the effects of this virus in these populations.

Sex ratio is variable and increasingly male biased at two colonies of Magellanic Penguins.

Sex ratios are commonly skewed and variable in wild populations, but few studies track temporal trends in this demographic parameter. We examined variation in the operational sex ratio at two protected and declining breeding colonies of Magellanic Penguins (Spheniscus magellanicus) in Chubut, Argentina. Penguins from the two colonies, separated by 105 km, migrate north in the non-breeding season and have overlapping distributions at sea. Conditions during the non-breeding season can impact long-term trends in operational sex ratio (i.e., through sex-specific survival) and interannual variation in operational sex ratio (i.e., through sex-specific breeding decisions). We found an increasingly male-biased operational sex ratio at the two disparate colonies of Magellanic Penguins, which may contribute to continued population decline. We also found that the two colonies showed synchronous interannual variation in operational sex ratio, driven by variation in the number of females present each year. This pattern may be linked to sex-specific overwintering effects that cause females to skip breeding, i.e., to remain at sea rather than returning to the colony to breed, more often than males. Contrary to our predictions, colony-wide reproductive success was not lower in years with a more male-biased operational sex ratio. We did find that males showed more evidence of fighting and were less likely to pair when the operational sex ratio was more male biased. Our results highlight an indirect mechanism through which variation in the operational sex ratio can influence populations, through a higher incidence of fighting among the less abundant sex. Because biased sex ratios can reduce the size of the breeding population and influence rates of conflict, tracking operational sex ratio is critical for conservation.

Lateralization (handedness) in Magellanic penguins.

Lateralization, or asymmetry in form and/or function, is found in many animal species. Brain lateralization is considered adaptive for an individual, and often results in "handedness," "footedness," or a side preference, manifest in behavior and morphology. We tested for lateralization in several behaviors in a wild population of Magellanic penguins Spheniscus magellanicus breeding at Punta Tombo, Argentina. We found no preferred foot in the population (each penguin observed once) in stepping up onto an obstacle: 53% stepped up with the right foot, 47% with the left foot (n = 300, binomial test p = 0.27). We found mixed evidence for a dominant foot when a penguin extended a foot for thermoregulation, possibly depending on the ambient temperature (each penguin observed once). Penguins extended the right foot twice as often as the left foot (n = 121, p < 0.0005) in 2 years when we concentrated our effort during the heat of the day. In a third year when we observed penguins early and late in the day, there was no preference (n = 232, p = 0.59). Penguins use their flippers for swimming, including searching for and chasing prey. We found morphological evidence of a dominant flipper in individual adults: 60.5% of sternum keels curved one direction or the other (n = 76 sterna from carcasses), and 11% of penguins had more feather wear on one flipper than the other (n = 1217). Right-flippered and left-flippered penguins were equally likely in both samples (keels: p = 0.88, feather wear: p = 0.26), indicating individual but not population lateralization. In fights, aggressive penguins used their left eyes preferentially, consistent with the right side of the brain controlling aggression. Penguins that recently fought (each penguin observed once) were twice as likely to have blood only on the right side of the face (69%) as only on the left side (31%, n = 175, p < 0.001). The proportion of penguins with blood only on the right side increased with the amount of blood. In most fights, the more aggressive penguin used its left eye and attacked the other penguin's right side. Lateralization depended on the behavior tested and, in thermoregulation, likely on the temperature. We found no lateralization or mixed results in the population of Magellanic penguins in three individual behaviors, stepping up, swimming, and thermoregulation. We found lateralization in the population in the social behavior fighting.

Marathon penguins - Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period.

Migratory species often roam vast distances bringing them into contact with diverse conditions and threats that could play significant roles in their population dynamics. This is especially true if long-range travels occur within crucial stages of a species' annual life-cycle. Crested penguins, for example, usually disperse over several hundreds of kilometres after completing the energetically demanding breeding season and in preparation for the costly annual moult. A basic understanding of crested penguins' pre-moult dispersal is therefore paramount in order to be able to assess factors affecting individual survival. The Fiordland penguin, or Tawaki, the only crested penguin species breeding on the New Zealand mainland, is currently one of the least studied and rarest penguin species in the world. We successfully satellite tracked the pre-moult dispersal of 17 adult Tawaki from a single colony located in the species' northern breeding distribution. Over the course of 8-10 weeks the penguins travelled up to 2,500 km away from their breeding colony, covering total swimming distances of up to 6,800 km. During outbound travels all penguins headed south-west within a well-defined corridor before branching out towards two general trip destinations. Birds leaving in late November travelled towards the Subtropical Front some 800 km south of Tasmania, whereas penguins that left in December headed further towards the subantarctic front. Using K-select analysis we examined the influence of oceanographic factors on the penguins' dispersal. Water depth, surface current velocity and sea level anomalies had the greatest influence on penguin movements at the subantarctic Front, while sea surface temperature and chlorophyll a concentration were key for birds travelling to the subtropical front. We discuss our findings in the light of anthropogenic activities (or lack thereof) in the regions visited by the penguins as well as the potential consequences of Tawaki pre-moult dispersal for the species' breeding distribution on the New Zealand mainland.

Addressing Criticisms of Large-Scale Marine Protected Areas.

Designated large-scale marine protected areas (LSMPAs, 100,000 or more square kilometers) constitute over two-thirds of the approximately 6.6% of the ocean and approximately 14.5% of the exclusive economic zones within marine protected areas. Although LSMPAs have received support among scientists and conservation bodies for wilderness protection, regional ecological connectivity, and improving resilience to climate change, there are also concerns. We identified 10 common criticisms of LSMPAs along three themes: (1) placement, governance, and management; (2) political expediency; and (3) social-ecological value and cost. Through critical evaluation of scientific evidence, we discuss the value, achievements, challenges, and potential of LSMPAs in these arenas. We conclude that although some criticisms are valid and need addressing, none pertain exclusively to LSMPAs, and many involve challenges ubiquitous in management. We argue that LSMPAs are an important component of a diversified management portfolio that tempers potential losses, hedges against uncertainty, and enhances the probability of achieving sustainably managed oceans.

Population regulation in Magellanic penguins: what determines changes in colony size?

Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus) colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces) and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north--which were established during the last decades--increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results reaffirm the idea that individual colony trends do not provide confident indicators of population health, highlighting the need to redefine the scale for the study of population changes.

Pollution, habitat loss, fishing, and climate change as critical threats to penguins.

Cumulative human impacts across the world's oceans are considerable. We therefore examined a single model taxonomic group, the penguins (Spheniscidae), to explore how marine species and communities might be at risk of decline or extinction in the southern hemisphere. We sought to determine the most important threats to penguins and to suggest means to mitigate these threats. Our review has relevance to other taxonomic groups in the southern hemisphere and in northern latitudes, where human impacts are greater. Our review was based on an expert assessment and literature review of all 18 penguin species; 49 scientists contributed to the process. For each penguin species, we considered their range and distribution, population trends, and main anthropogenic threats over the past approximately 250 years. These threats were harvesting adults for oil, skin, and feathers and as bait for crab and rock lobster fisheries; harvesting of eggs; terrestrial habitat degradation; marine pollution; fisheries bycatch and resource competition; environmental variability and climate change; and toxic algal poisoning and disease. Habitat loss, pollution, and fishing, all factors humans can readily mitigate, remain the primary threats for penguin species. Their future resilience to further climate change impacts will almost certainly depend on addressing current threats to existing habitat degradation on land and at sea. We suggest protection of breeding habitat, linked to the designation of appropriately scaled marine reserves, including in the High Seas, will be critical for the future conservation of penguins. However, large-scale conservation zones are not always practical or politically feasible and other ecosystem-based management methods that include spatial zoning, bycatch mitigation, and robust harvest control must be developed to maintain marine biodiversity and ensure that ecosystem functioning is maintained across a variety of scales.

Mercury levels in feathers of Magellanic penguins.

Feathers are useful to determine mercury (Hg) contamination. We evaluated the mercury concentration in feathers of Magellanic penguins (Spheniscus magellanicus) age 1.5 years to 25 years at Punta Tombo, Argentina before and during their molt. Mercury ranged between <1.4 and 367 ng/g dry weight, with three extreme high values (8996 ng/g, 3011 ng/g and 1340 ng/g) all in young adults. The median concentration was lowest for juveniles and significantly higher for adults but with high variation among older adults. Males and females had similar mercury loads. Compared with other penguin species, concentrations in Magellanic penguins were low. Mercury levels for Magellanic penguins in the Southwest Atlantic for older adults averaged 206±98 ng/g, and serve as a baseline for biomonitoring and/or ecotoxicological studies.

Magellanic penguin mortality in 2008 along the SW Atlantic coast.

Magellanic penguins migrate from Patagonia reaching northern Argentina, Uruguay, and southern Brazil on their winter migration, in parallel with the seasonal pulse of anchovy spawning. In 2008, Magellanic penguins went further north than usual. Many died and a few swam nearly to the Equator. Twelve groups surveyed 5000 km of coastline encountering 3371 penguins along the coast. Most penguins arrived in northern Brazil (68.4%) without petroleum (2933, 87%). Almost all penguins without petroleum were juveniles (2915, 99%) and 55% were alive when found. Penguins were dehydrated, anemic, hypothermic, and emaciated. Of the penguins with petroleum, 13% arrived in the southern half of Brazil, showing that petroleum pollution remains a problem along the SW Atlantic coast. The mortality occurred in the winter of 2008 when sea surface temperature were unusually cold perhaps reducing the prey for penguins.

Chronic oil pollution harms Magellanic penguins in the Southwest Atlantic.

Petroleum pollution is a problem for seabirds along the Southwest Atlantic coast. Twenty-five groups from Salvador, Brazil (12 degrees 58'S) to San Antonio Oeste, Argentina (40 degrees 43'S) survey or rehabilitate sick or oiled seabirds. Four groups, one each in Brazil and Uruguay, and two in Argentina, kept counts of birds found alive and in need of rehabilitation. An average of 63.7% of the seabirds found were Magellanic penguins (Spheniscus magellanicus), with 3869 reported since 1987. Mainly adult penguins were found in Argentina (1605 of 2102 penguins of known age class) and Uruguay (158 of 197). Juveniles were most common in Brazil (234 of 325). Oil fouling was the most frequent cause of injury or sickness. The number of oiled penguins reported in their wintering range has greatly increased since the early 1990s and is strongly correlated with petroleum exports from Argentina. Our results show that chronic petroleum pollution is a problem for wildlife from Southern Brazil through Northern Argentina, and regulations and enforcement are failing to protect living resources.