Antarctic Research Trust

Stanley, Falkland Islands

Antarctic Research Trust

Stanley, Falkland Islands
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Rey A.R.,CONICET | Putz K.,Antarctic Research Trust | Simeone A.,Andrés Bello University | Hiriart-Bertrand L.,Andrés Bello University | And 5 more authors.
Emu | Year: 2013

How closely related marine organisms mitigate competition for resources while foraging at sea is not well understood, particularly the relative importance of interspecific and intraspecific mitigation strategies. Using location and time-depth data, we investigated species-specific and sex-specific foraging areas and diving behaviour of the closely related Humboldt (Spheniscus humboldti) and Magellanic (S. magellanicus) Penguins breeding in sympatry at Islotes Puñihuil in southern Chile during the chick-rearing period. The average duration of foraging trips was <20h and did not differ significantly between species or between sexes of each species. Magellanic Penguins made significantly deeper and longer dives than Humboldt Penguins. Males of both species made significantly longer dives than females. Total distance travelled per foraging trip was significantly greater for males than for females, and females made more direct trips (less sinuous) than males. Foraging effort was concentrated in waters up to 15km to the west and south-west of the colony. The overlap in density contours was lower between species than between sexes within a species. In general, dive characteristics and foraging areas differed more between Magellanic and Humboldt Penguins than between the sexes of each species. In contrast to the findings of studies of flying seabirds, the foraging behaviour of these penguins differs more between species than between sexes. © 2013 Bird Life Australia.

Reyes-Arriagada R.,Austral University of Chile | Hiriart-Bertrand L.,University of California at San Diego | Riquelme V.,Austral University of Chile | Simeone A.,Andrés Bello University | And 3 more authors.
Avian Conservation and Ecology | Year: 2013

Worldwide marine protected areas (MPAs) have been designated to protect marine resources, including top predators such as seabirds. There is no conclusive information on whether protected areas can improve population trends of seabirds when these are further exploited as tourist attractions, an activity that has increased in past decades. Humboldt Penguins (Spheniscus humboldti) and Magellanic Penguins (S. magellanicus) breed sympatrically on Puñihuil Islets, two small coastal islands off the west coast of Chiloé Island (41° S) in southern Chile that are subject to exploitation for tourism. Our goal was to compare the population size of the mixed colony of Humboldt and Magellanic Penguins before and after protection from unregulated tourism and freely roaming goats in 1997. For this purpose, two censuses were conducted in 2004 and 2008, and the numbers compared with those obtained in 1997 by other authors. The proportion of occupied, unoccupied, and collapsed/flooded burrows changed between years; there were 68% and 34% fewer collapsed burrows in 2004 and 2008, respectively, than in 1997. For the total number of burrows of both species, we counted 48% and 63% more burrows in 2004 and 2008, respectively, than in 1997. We counted 13% more burrows of Humboldt Penguins in 2008 than in 1997, and for Magellanic Penguins, we estimated a 64% increase in burrows in 2008. Presumably, this was as a result of habitat improvement attributable to the exclusion of tourists and the removal of goats from the islets. Although tourist visits to the islets are prohibited, tourism activities around the colonies are prevalent and need to be taken into account to promote appropriate management. © 2013 by the author(s).

Trathan P.N.,British Antarctic Survey | Garcia-Borboroglu P.,CONICET | Boersma D.,University of Washington | Bost C.-A.,CNRS Chizé Center for Biological Studies | And 13 more authors.
Conservation Biology | Year: 2015

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. © 2014 The Authors.

Putz K.,Antarctic Research Trust | Hiriart-Bertrand L.,University of Santiago de Chile | Hiriart-Bertrand L.,Andrés Bello University | Simeone A.,Andrés Bello University | And 3 more authors.
Waterbirds | Year: 2011

Various mitigation measures have been implemented to reduce incidental seabird mortality in longline and trawl fisheries but little attention has been given to artisanal fishing. In the 2008/09 breeding season, during a study of foraging of Humboldt, Spheniscus humboldti, and Magellanic Penguins, S. magellanicus, breeding on Puñihuil islets, southern Chile, a Magellanic Penguin equipped with a time-depth recorder became entangled and subsequently drowned in a gill net set for Corvina Drum (Cilus gilberti). The device was returned by fishermen and the data appear to be the first documented case of such a drowning in a marine, air-breathing vertebrate. According to the data, while diving to a depth of more than 50 m, the bird became entangled and drowned, remaining below 60 m for nearly 21 hours until the net was hauled. Although only a single incident is reported, there are indications that incidental mortality of penguins, other seabirds and marine mammals is more common in artisanal fisheries than previously anticipated.

Putz K.,Antarctic Research Trust | Raya Rey A.,CONICET | Raya Rey A.,National University of Tierra del Fuego | Hiriart-Bertrand L.,Costa Humboldt | And 3 more authors.
Global Ecology and Conservation | Year: 2016

Ten Humboldt (Spheniscus humboldti) and eight Magellanic Penguins (S. magellanicus) were successfully equipped with satellite transmitters in March 2009 on Islotes Puñihuil in central south-Chile to follow their post-moult dispersal. Overall, Humboldt Penguins could be followed for a mean period of 49 ±18 days (range: 25-93) and Magellanic Penguins for 57 ±12 days (range 35-68). Irrespective of species and sex, seven study birds remained in the vicinity of their breeding ground throughout the transmission period. All other penguins moved northwards, either only a relatively short distance (max 400 km) to Isla Mocha at 38°S (n= 3) or further north beyond 35°S (n= 8). However, eight of these birds (73%) turned south again towards the end of the individual tracking periods. The total area used by both species during the tracking period was restricted to a coastal area stretching from the breeding site at 42°S about 1000 km to the north at about 32°S. The area used by Humboldt penguins overlapped by 95% the area used by Magellanic penguins, whereas the area used by the latter species was much larger and overlapped only by 45% with the area used by Humboldt penguins. Overall, our results indicate that Magellanic Penguins in the Pacific Ocean are probably less migratory than their conspecifics on the Atlantic side, while Humboldt Penguins appear to be more migratory than previously anticipated. In general, there was a poor relationship between preferred foraging areas and chlorophyll-a, as a proxy for primary productivity, indicating the limitations of using remote-sensed primary productivity as a proxy to interpret the foraging behaviour of marine predators. In addition, there was also no clear relationship between the preferred foraging areas and the amount of regional fish catches by artisanal fishery. © 2016 The Authors.

Raya Rey A.,CONICET | Bost C.-A.,CNRS Chizé Center for Biological Studies | Schiavini A.,CONICET | Schiavini A.,Wildlife Conservation Society | Putz K.,Antarctic Research Trust
Journal of Ornithology | Year: 2010

This study investigates the movements of Magellanic Penguins Spheniscus magellanicus breeding on Isla Martillo during the early chick-rearing period. Foraging paths were reconstructed using GPS loggers that registered the penguins′ geographic position, water temperature and depth at regular intervals. The relationship between penguins′ movements and search strategies, tide and tidal currents were assessed. Mean trip duration was on average 14.7 ± 6.9 h (33% overnight), and the maximum distance reached was 24 ± 10 km. All penguins studied foraged to the east of the colony. We identified three phases based on the sinuosity and speed of the trajectory: transit, central and return. Foraging effort was higher during the central phase, followed by the transit phase, and lower in the return phase. Foraging success, measured as the percentage of time at the bottom during each phase, was also highest during the central phase. In all birds studied, the central phase of the foraging trip took place during ebb tide, and birds travelled to the foraging areas with flow tide running in the same direction of displacement. Our study suggests that penguins take advantage of tidal currents to facilitate their movements to and from the main foraging area, thereby reducing the energy expended. Moreover, we suggest that piscivorous diving birds may enhance their catch rate during ebb tide when fish are more concentrated near the channel bed. © 2010 Dt. Ornithologen-Gesellschaft e.V.

Pistorius P.A.,Nelson Mandela Metropolitan University | Baylis A.,Falklands Conservation | Crofts S.,Falklands Conservation | Putz K.,Antarctic Research Trust
Antarctic Science | Year: 2012

After an extended period of sporadic sightings of small numbers of king penguins at the Falkland Islands, they established themselves on Volunteer Point, situated at the north-east of the islands, by the late 1970s. By 1980, a small breeding population was present which yielded some 40 fledglings during that same year. Since 1991, the population has been monitored annually and the resulting fledgling counts analysed to assess population trends. The population demonstrated a significant increase over the past three decades, at about 10% per annum, with time explaining 75% of the variation in count data. The current population is estimated to be 720 breeding pairs. Despite several authors having alluded to the existence of a large colony of king penguins at the Falklands prior to human exploitation, we found no evidence in support of this. We furthermore found no evidence in the literature in support of exploitation for king penguin oil during the 19th century. Unlike at other breeding sites, increasing numbers of king penguins at the Falklands is consequently unlikely to be a recovery response following exploitation, but rather an indication of either increased immigration or of improved feeding conditions. © Copyright 2012 Antarctic Science Ltd.

Pedrana J.,Instituto Nacional de Tecnologia Agropecuaria | Pon J.P.S.,CONICET | Isacch J.P.,CONICET | Leiss A.,Calle 12 Y 53 Torre II Piso 14 | And 7 more authors.
Ornitologia Neotropical | Year: 2015

Detailed knowledge of the migratory strategies is important to understand the ecology and evolution of migration and the conservation of migratory birds The Argentinean federal government declared sheldgeese (Chloephaga spp.) pests in 1930, claiming that they reduce crop yield. Currently sheldgeese have suffered severe reductions in their populations and are the focus of serious conservation concern. From September to April they breed in southern Patagonia (Argentina and Chile) while from May to September they winter mainly in the southern Pampas (central east Argentina). The precise knowledge of their migratory routes is essential to ensure protection of necessary resources and sites needed on their annual journeys. Here, by using a satellite transmitter for the first time we unravel themigration route of an Upland Goose (Chloephaga picta), a species endemic to southern South America with an unknown migration strategy. We received data for 121 days (from September 2014 to January 2015). During this time, the bird migrated 1485 km from the wintering grounds in Buenos Aires Province to the breeding area in Santa Cruz province, Patagonia. Part of the migration route was over the sea. The largest displacement was 817 km in 19 hours, representing a minimum mean speed of 43 km h-1. © The Neotropical Ornithological Society.

Rey A.R.,CONICET | Putz K.,Antarctic Research Trust | Scioscia G.,CONICET | Lthi B.,Antarctic Research Trust | And 2 more authors.
Emu | Year: 2012

Understanding the foraging behaviour of seabirds and its plasticity is vital to establish their role in marine food webs and their use as indicators of change in the availability of prey. The foraging behaviour of penguins is known to differ with locality, sex, stage of breeding and between years. We studied the diving behaviour of breeding Magellanic Penguins (Spheniscus magellanicus), using time-depth recorders, during incubation and brooding in the 200304 and 200405 breeding seasons at Isla Martillo, Tierra del Fuego, Argentina. Foraging trips during the incubation period were longer than those during the brooding period for both sexes in both years of the study. Sex-related differences in foraging behaviour were observed during the incubation stage. During the incubation stage females performed longer foraging trips than males, foraging effort was lower, and did not dive as deep as males in both years. Foraging success was lower for females than males during incubation only in 2003. Our results suggest that sexual differences, expressed as differences in the foraging parameters of males and females, only develop when Fuegian Sprat (Sprattus fuegensis), the main prey in this locality, is not abundant close to the colony. Females may be extending the volume of water they can exploit by extending the duration of trips (horizontal distance), whereas males do so by diving deeper (vertical distance). Our results show the fundamental differences in foraging strategies between the sexes in Magellanic Penguin are a consequence of environmental conditions not morphological differences between sexes. © 2012 BirdLife Australia.

Putz K.,Antarctic Research Trust | Trathan P.N.,Natural Environment Research Council | Pedrana J.,CONICET | Collins M.A.,Natural Environment Research Council | And 2 more authors.
PLoS ONE | Year: 2014

Most studies concerning the foraging ecology of marine vertebrates are limited to breeding adults, although other life history stages might comprise half the total population. For penguins, little is known about juvenile dispersal, a period when individuals may be susceptible to increased mortality given their naïve foraging behaviour. Therefore, we used satellite telemetry to study king penguin fledglings (n = 18) from two sites in the Southwest Atlantic in December 2007. The two sites differed with respect to climate and proximity to the Antarctic Polar Front (APF), a key oceanographic feature generally thought to be important for king penguin foraging success. Accordingly, birds from both sites foraged predominantly in the vicinity of the APF. Eight king penguins were tracked for periods greater than 120 days; seven of these (three from the Falkland Islands and four from South Georgia) migrated into the Pacific. Only one bird from the Falkland Islands moved into the Indian Ocean, visiting the northern limit of the winter pack-ice. Three others from the Falkland Islands migrated to the eastern coast of Tierra del Fuego before travelling south. Derived tracking parameters describing their migratory behaviour showed no significant differences between sites. Nevertheless, generalized linear habitat modelling revealed that juveniles from the Falkland Islands spent more time in comparatively shallow waters with low sea surface temperature, sea surface height and chlorophyll variability. Birds from South Georgia spent more time in deeper waters with low sea surface temperature and sea surface height, but high concentrations of chlorophyll. Our results indicate that inexperienced king penguins, irrespective of the location of their natal site in relation to the position of the APF, develop their foraging skills progressively over time, including specific adaptations to the environment around their prospective breeding site. © 2014 Pütz et al.

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