Studying trophic feeding habits and their variation over time is crucial for understanding individual population success. Although many generalist feeders’ populations appear to use diverse resources, they are often composed of individuals that specialize in only a subset these phenomenon known as specialization (ITS). The South American sea lion (SASL) (Otaria flavescens), widely distributed along the coast, an opportunistic predator with diet, making it good model studying ITS. We aimed...

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 525:245-260 (2015) - DOI: https://doi.org/10.3354/meps11214 Ontogenetic dietary changes in male South American fur seals Arctocephalus australis Patagonia Damián G. Vales1,*, Luis Cardona2, Néstor A. García1, Lisette Zenteno2, Enrique Crespo1 1Laboratory of Mammals, Centro Nacional Patagónico (CENPAT),...

The human exploitation of marine resources is characterised by the preferential removal largest species. Although this expected to modify structure food webs, we have a relatively poor understanding potential consequences such alteration. Here, take advantage collection ancient consumer tissues, using stable isotope analysis and SIBER assess changes in coastal webs South-western Atlantic through second half Holocene as result sequential hunter-gatherers, western sealers modern fishermen....

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 538:23-34 (2015) - DOI: https://doi.org/10.3354/meps11464 Latitudinal changes in structure of marine food webs Southwestern Atlantic Ocean F. Saporiti1,*, S. Bearhop2, D. G. Vales3, L. Silva3, Zenteno1, M. Tavares4, E. A. Crespo3,5, Cardona1 1Department Animal Biology and Institut de Recerca la Biodiversitat...

Stable isotope analyses have become an important tool in reconstructing diets, analysing resource use patterns, elucidating trophic relations among predators and understanding the structure of food webs. Here, we stable carbon nitrogen ratios bone collagen to reconstruct compare isotopic niches adult South American fur seals (Arctocephalus australis; n = 86) sea lions (Otaria flavescens; 49) - two otariid species with marked morphological differences Río de la Plata estuary (Argentina...

ABSTRACT South American fur seals ( Arctophoca australis ) inhabiting the Río de la Plata plume and adjoining areas are known to forage upon a wide range of prey (i.e. pelagic, demersal benthic species). Since 1960s, trawlers have operated in area, targeting primarily species. Carbon nitrogen stable isotope ratios from 54 adult male dead stranded along coast southern Brazil 1994 2011 were analysed investigate whether intensification fishing since mid‐1990s has reduced availability growing...

Abstract The dusky dolphin Lagenorhynchus obscurus occurs in the Southern Hemisphere, where it is restricted to coastal temperate areas. This study aimed characterize feeding ecology of dolphins inhabiting northern and central Patagonia by using δ 13 C 15 N stable isotope ratios skin samples. We searched for evidence geographical seasonal variation diet we explored dietary differences between sexes. Significant were found among 4 gulfs under study. Skin samples from Golfo San Matías Jorge...

Abstract Stable carbon and nitrogen isotope ratios in the skeletal elements of both ancient modern marine species from Beagle Channel were used to compare structure Late Holocene food webs, predict potential changes as a result Sea Surface Temperature (SST) increase region. Complementary, shells limpets mussels isotopically analysed explore isotopic baseline webs through time after an appropriate correction for shifts. Results confirmed declining pattern primary productivity during Channel....

SUMMARY We analysed population dynamics of the louse Antarctophthirus microchir in pups South American sea lion, Otaria flavescens , at Punta León rookery (Argentina) over a period 2 years. A total 136 were aged and marked beginning lactation ashore, then sampled for lice different times within 30 days. Sampling was restricted to chest belly, two sites where especially abundant. This concentration on ventral areas might protect from thermal stress austral summer. Infestation patterns ⩽3 days...

Abstract Although the body size of consumers may be a determinant factor in structuring food webs, recent evidence indicates that fail to fully explain differences resource use patterns predators some situations. Here we compared trophic niche three sympatric and sexually dimorphic air‐breathing marine (the South American sea lion, Otaria flavescens , fur seal, Arctocephalus australis Magellanic penguin, Spheniscus magellanicus ) areas Southwestern Atlantic Ocean (Río de la Plata adjoining...

Natural or human-induced environmental changes can modify the structure of ecological communities and thus alter food web interactions. After collapse hake stocks (Merluccius hubbsi) provoked by fisheries over Patagonian shelf in 1997 profound have taken place community, including long-term dietary shifts some marine vertebrate predators. Stable carbon (δ13C) nitrogen (δ15N) isotope ratios bone collagen subadult adult male South American fur seals (Arctocephalus australis) were measured for...

Abstract We analyzed the δ 13 C and 15 N values in vibrissae of captive adult breeding South American sea lions ( Otaria byronia ) fed at a constant diet then used this information to analyze change stable isotope along from wild individuals. The overall diet‐to‐vibrissa discrimination factor animals was 3.0‰ ± 0.1‰ for 3.6‰ N, but ratios fluctuated periodically despite diet. male declined end season, whereas female increased during central part pregnancy peaked lactation. specimens also...

Abstract Killer whales ( Orcinus orca ) are highly mobile, large marine apex predators that inhabit all oceans. Despite being the most conspicuous top predator, little is known about their ecology along Patagonia, Argentina. Here, we used carbon (δ 13 C) and nitrogen 15 N) isotope analysis of bone dentine collagen from killer n = 13) stranded in northern Patagonia during period 1970–2014 to assess trophic ecology. A model‐based clustering identified three distinct groups related with...

The northern coast of the San Jorge Gulf, Atlantic Patagonia, is recognised as a marine biodiversity hot spot and designated priority conservation area. Among mammals, three species pinnipeds inhabit region. While South American sea lions ( Otaria flavescens) have higher abundance larger number colonies than fur seals Arctocephalus australis), few individuals Southern elephant seal Mirounga leonina) reside in Nevertheless, little known about distribution these before 18th century, when...

Humans have altered marine ecosystems over very long-time scales and historical data is often needed to understand the true magnitude of human impacts. The Southwest Atlantic Ocean has a long history large-scale removal vertebrates due whaling, sealing, fishing in past three centuries. Historical catch records are crucial assessing conservation status these historically over-exploited populations setting suitable recovery goals. However, several gaps exploitation many limit our ability judge...

Among Anoplura, the family Echinophthiriidae includes species that infest pinnipeds and otters. Previous evidence obtained from infested by echinophthiriids, specifically seals, indicates flippers are preferred infestation sites, while lice fur seals select areas in pelage. We studied habitat selection of Antarctophthirus microchir on South American sea lion pups (Otaria flavescens Shaw, 1800) Patagonia, Argentina, during austral summer 2009. found a clear pattern selection: eggs laid dorsal...

Increasing knowledge of the biodiversity parasitic copepods in Argentinean Sea will provide a baseline against which changes distribution marine biota can be detected. We new information on 13 known species gathered from 11 fishes Sea, including 7 host records and 9 locality records. These are: Bomolochus globiceps (Vervoort et Ramírez, 1968) Nothobomolochus cresseyi Timi Sardella, 1997 (Bomolochidae Sumpf, 1871); Brasilochondria riograndensis Thatcher Pereira, 2004 (Chondracanthidae Milne...