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Handley J.M.,Nelson Mandela Metropolitan University | Baylis A.M.M.,Deakin University | Brickle P.,South Atlantic Environmental Research Institute | Pistorius P.,Nelson Mandela Metropolitan University
Polar Biology | Year: 2016

Knowledge of diet is critical in interpreting the ecological roles of marine top predators and provides information towards their conservation and management. The Falkland Islands hold the largest number of breeding gentoo penguins. Yet knowledge of gentoo penguin diet at the Falklands is limited to either broad taxonomic divisions of prey items or dietary samples collected only on a single day. This study is the first to investigate gentoo penguin diet at Cow Bay, Falklands, to the species level, over repeated sampling intervals during the breeding period. Through stomach content analysis, we determined diet over a large temporal scale (2002/2003/2004–2011/2012/2013) and between the guard and crèche periods of chick rearing. The principle prey item by reconstituted mass was rock cod fish Patagonotothen spp., for all periods (47–78 %) except that of the 2012/2013 crèche period (19 %) when Falkland herring Sprattus fugensis made up the bulk of the diet (52 %). Of the cephalopods recovered, Patagonian squid Doryteuthis gahi was prominent (1–24 %), while crustaceans contributed negligibly to gentoo penguin diet. Our findings revealed that gentoo penguins breeding at the Falkland Islands were primarily demersal foragers with an ability for pelagic feeding. Diet choice appears to reflect prey availability. © 2015, Springer-Verlag Berlin Heidelberg.

Brown J.,University of Aberdeen | Brickle P.,University of Aberdeen | Brickle P.,South Atlantic Environmental Research Institute | Scott B.E.,University of Aberdeen
Journal of Helminthology | Year: 2013

The parasite fauna of juvenile Dissostichus eleginoides, while they inhabit the Falkland's shelf, was examined, giving new detailed information on spatial, ontogenic and seasonal variations. A total of 24,943 parasites from 15 different taxa were found in the stomach of 502 individual fish. Parasite species composition and abundance allowed separation of toothfish by area between the north-west and south-east of the Falklands. The digenean, Elytrophalloides oatesi, and the nematodes, Hysterothylacium spp. and Anisakis spp., were the most common, all with a prevalence >20%. For some seasons ontogenic changes in abundance were significant in these three parasite taxa, and this is discussed in terms of ontogenic and seasonal changes in diet. Elytrophalloides oatesi and Hysterothylacium spp. showed spatial and seasonal differences in abundance with greater numbers in the warmer waters of the north-west and during the summer months. Differences in abundance of E. oatesi between the Falklands and other regions indicate its potential for use as a biological tag to study toothfish movements and population structure; however, more seasonal data would be required before this technique could be used. © Cambridge University Press 2012.

Granadeiro J.P.,University of Aveiro | Brickle P.,South Atlantic Environmental Research Institute | Catry P.,Eco ethology Research Unit
Animal Conservation | Year: 2014

Fisheries can have profound impacts on the structure and functioning of marine ecosystems and affect seabird populations. For seabirds, impacts can include direct mortality in fishing gear, but fisheries also represent an abundant source of food that may otherwise be inaccessible. Previous studies with seabirds have revealed the occurrence of individual foraging specializations, and therefore in scavenging species some individuals may have a higher propensity to feed on fisheries discharges than the rest of the population. Here we used recently developed techniques (spatio-temporal match of positions) to detect interactions between black-browed albatrosses Thalassarche melanophris and fishing vessels, and also stable isotope analysis of tissues with different turnovers, to investigate long-term individual specialization in fishery waste products. We combined global positioning system tracking data from 89 birds with vessel monitoring system data from the entire fleet operating around the Falklands Islands, in 2009 and 2011. Interactions with vessels (freezer/factory bottom trawlers) occurred in 15 out of 89 independent albatross trips. Among individuals tracked in both years, those that associated with fisheries in 2009 were not more likely to do so again in 2011. Carbon and nitrogen isotopic signatures in whole blood and feathers of albatrosses that interacted with trawlers were similar to those of individuals that did not. Also, we found no correlation between feather and blood isotopic ratios of carbon or nitrogen, indicating no long-term consistency in the isotopic niche of study birds. These results suggest no specialization of individual albatrosses with regard to fisheries. Studies of other albatrosses have also failed to show long-term trophic consistency, which may indicate that scavenging albatrosses, a group particularly threatened by fisheries activity, do not specialize in discards. Therefore, any management actions leading to a reduction of discards will be beneficial, decreasing the numbers of birds behind vessels and consequently the likelihood of incidental mortality. © 2013 The Zoological Society of London.

Brickle P.,South Atlantic Environmental Research Institute
Journal of Fish Biology | Year: 2012

Seasonal changes in relative abundance and biomass of nektonic predators were analysed on the eastern Patagonian Shelf and continental slope; one of the most productive large marine ecosystems of the southern hemisphere. Several migratory types were revealed for species belonging to either temperate or sub-Antarctic faunas. Despite high productivity, only a few large nektonic predators spend their entire life cycle on the eastern Patagonian Shelf and use only a small proportion of the meso-nektonic resource. Most of the resource is exploited by non-resident nektonic migrants, which move to the area from distant spawning grounds. Pelagic and demersal sharks and skates, the squid Illex argentinus, tunas and gadoids migrate to the eastern part of the Patagonian Shelf to feed at different times of the year; arriving in seasonal waves according to their life cycle and spawning seasonality. Some deepwater fishes and squid migrate onto the shelf as juveniles to harvest the resource, and then return to deepwater habitat as adults. It is hypothesized that the large biomass of meso-planktonic and meso-nektonic consumers prevents most higher-trophic level predators from establishing spawning populations in this area, as their larvae and fry would be overwhelmed by predation. Instead, the higher-trophic level predators establish spawning and nursery grounds elsewhere and arrive to feed on the meso-planktonic and meso-nektonic resources after they have outgrown their own stages of predation vulnerability. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Auge A.A.,South Atlantic Environmental Research Institute
Polar Biology | Year: 2016

Plastic pollution is becoming an increasing issue for wildlife throughout the world. Even remote areas with relatively little human activity are affected. The Falkland Islands are a South Atlantic archipelago with a small human population (<3000), mostly concentrated in one town, Stanley. One hundred regurgitated pellets from turkey vultures (Cathartes aura) were collected in Stanley in July and August 2015 to investigate the diet and amount of anthropogenic debris (human-made artificial products) ingested. The frequency of occurrence of anthropogenic debris was 58 % of pellets for plastic, 25 % for glass, 23 % for paper, 21 % for aluminium and 3 % for fabric. Aside from anthropogenic debris, the majority of pellets were made of sheep wool (on average 29 % of the volume), feathers (19 %) and vegetation (18 %). On average, when present, anthropogenic debris corresponded to 16.1 % of the mass of each pellet, equivalent to 1.6 g. The turkey vultures are known to feed in the open-air rubbish dump near the town. This study highlights that they ingest significant amounts of anthropogenic debris. Further investigations should be undertaken to monitor and identify potential health effects. Other birds also use the dump and may be affected. Even in such remote sparsely populated islands, pollution may be a significant issue. Rubbish management could be put in place to limit birds from feeding at the dumps. A low human population density may not indicate low pollution impacts on wildlife and the environment and should be investigated further in the Falkland Islands and at other remote islands. © 2016 Springer-Verlag Berlin Heidelberg

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