Shifting niches of marine predators due to human exploitation: the diet of the South American sea lion (Otaria flavescens) since the late Holocene as a case study

  title={Shifting niches of marine predators due to human exploitation: the diet of the South American sea lion (Otaria flavescens) since the late Holocene as a case study},
  author={Lisette Zenteno and Florencia Borella and Julieta G{\'o}mez Otero and Ernesto Luis Piana and Juan Bautista Belardi and Luis Alberto Borrero and Fabiana Saporiti and Luis Cardona and Enrique Alberto Crespo},
Abstract. Stable isotope ratios of carbon and nitrogen in archaeological and modern bone samples have been used to reconstruct the dietary changes of the South American sea lion Otaria flavescens from the late Holocene to the present in the southwestern Atlantic. We sampled bones from archaeological sites in northern-central and southern Patagonia, Argentina, and bones housed in modern scientific collections. Additionally, we analyzed the stable isotope ratios in ancient and modern shells of… 

Prehistoric and Modern Ecological Dynamics in Southern South American Marine Food Webs

  • J. Nye
  • Environmental Science, Geography
  • 2019
Author(s): Nye, Jonathan | Advisor(s): Fogel, Marilyn L | Abstract: Marine food webs in coastal southern South America are thought to have been impacted over time in response to humans in the late

Holocene changes in the trophic ecology of an apex marine predator in the South Atlantic Ocean

The trophic position of fur seals has changed through the Holocene in some South Atlantic regions, and a major dietary shift was observed in fur seals from Tierra del Fuego during the nineteenth century.

Back to the future? Late Holocene marine food web structure in a warm climatic phase as a predictor of trophodynamics in a warmer South‐Western Atlantic Ocean

A declining pattern of marine primary productivity during the Late Holocene in the Beagle Channel was confirmed and all the species that have undergone intense human exploitation significantly increased their trophic levels, highlighting the relevance of using zooarchaeological remains for providing predictions about marine food webs changes in the near future.

Isotopic niche partitioning between two apex predators over time

It is found that the South American fur seals and South American sea lions had distinct isotopic niches during the middle Holocene, and the progressive convergence of these two otariids during the second half of the 20th century and the beginning of the 21st century is most likely due to the increased reliance of South Brazilian fur seals on demersal prey.

Foraging behaviour of the South American sea lion (Otaria byronia) in two disparate ecosystems assessed through blubber fatty acid analysis

Comparison of fatty acid profiles of sea lions from two distinct oceanographic regions in northern and southern Chile shows how human intervention is being reflected in the tissues of a top predator in a natural environment.

Mouth gape determines the response of marine top predators to long-term fishery-induced changes in food web structure

The results are consistent with the changes in the length distribution of demersal fish species resulting from fishing and suggest that Franciscana dolphin has been the most benefited species of the three marine mammal species considered because of its intermediate mouth gape.

Using Chemical Elements to the Study of Trophic and Spatial Ecology in Marine Mammals of the Southwestern Atlantic Ocean

The ecology of marine mammals has been largely benefited from the use of biogeochemical markers. In this chapter we compiled information about studies using these tracers, with the aim of

Predicting habitat use by the Argentine hake Merluccius hubbsi in a warmer world: inferences from the Middle Holocene

Interestingly, average SST off Tierra del Fuego during the Middle Holocene was higher than currently and matched SST in the current southernmost onshore spawning aggregations, at latitude 47 °S, which indicates that increasing SST resulting from global warming will likely result into an increased abundance of adult Argentine hake onshore Tierra Del Fue go, as during theMiddle Holocene.

Jack of all prey, master of some: Influence of habitat on the feeding ecology of a diving marine predator

Gentoo penguins at the population level at the Falklands are indeed generalists, however, at individual colonies some specialization occurred to take advantage of locally available prey, resulting in these birds being classified as Type B generalists.



Historic diet change of the South American sea lion in Patagonia as revealed by isotopic analysis

Reinforced intraspecific competition and massive discard of pelagic fish likely contributed to the observed dietary shift, while the poorly developed industrial fishing off Tierra del Fuego did not facilitate a similar change there.

Trophic relationships of exotic anadromous salmonids in the southern Patagonian Shelf as inferred from stable isotopes

Diet predictions based on stable isotopes for Chinook salmon were indistinguishable from direct assessments of stomach contents of fish captured by bottom trawlers and overlapped widely with the diet of Magellanic penguins.

Trans-Holocene Marine Mammal Exploitation on San Clemente Island, California: A Tragedy of the Commons Revisited

Abstract Occupied from ca. 7040 B.C. to A.D. 1400, the Eel Point Site (CA-SCLI-43) on San Clemente Island, California represents one of the longest sequences of near-continuous marine resource


The study indicates that nitrogen, and in some cases carbon, isotopes can be used to assess reproductive strategies in marine mammals and when coupled with accurate age estimates based on bone growth regressions can be applied to historical or fossil otariids to gain insight into the flexibility of maternal strategies within and across species.


The sea lions from Puerto Quequen showed a diverse diet, mainly feeding on demersal and pelagic prey, and the main prey consumed by sea lions were teleost fish, followed by cephalopods and crustaceans.

Book review: Human Impacts on Seals, Sea Lions and Sea Otters: Integrating Archaeology and Ecology in the Northeast Pacific

The successful management and protection of animals rely on a basic understanding of their distributions, many of which have altered significantly over the last 10,000 years as a result of