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Punta Arenas, Chile

Torres D.,Pedro de Valdivia University | Acevedo J.,University of Magallanes | Torres D.E.,University of the Americas in Chile | Aguayo-Lobo A.,Instituto Antartico Chileno INACH
Polar Biology | Year: 2012

A vagrant adult male Subantarctic fur seal Arctocephalus tropicalis was observed among Antarctic fur seals A. gazella at Cape Shirreff, Livingston Island, Antarctica, which is located to ~4,190 and ~5,939 km from the nearest breeding colonies of Subantarctic fur seals. Although the colony of origin of this animal and the reason for its movement outside its distribution range are unknown, this sighting shows the high dispersal capacity of this species and provides an insight into possible changes in its distribution. Although this vagrant was not observed with females Antarctic fur seal, news sightings in the future could result in viable hybrid, and introgressive hybridization could represent a threat for Cape Shirreff population recovery, if still the population way to go to recover to presailing levels. © 2011 Springer-Verlag.

Cardenas C.A.,Victoria University of Wellington | Cardenas C.A.,Instituto Antartico Chileno INACH | Davy S.K.,Victoria University of Wellington | Bell J.J.,Victoria University of Wellington
Journal of the Marine Biological Association of the United Kingdom | Year: 2015

Experimental removals of the dominant canopy-forming kelp Ecklonia radiata were conducted at two sites on rocky walls in New Zealand and monitored for approximately 1.5 years. We hypothesized that the removal of the E. radiata canopy would affect the structure of subcanopy assemblages, such that there would be a reduction in sponge species richness and abundance. Furthermore, we investigated the biological and physical (predictor) variables that best explained variability in sponge assemblages after canopy removal. Canopy removal led to a community dominated by turf algae, which corresponded with a decrease in sponge abundance and richness. Our results suggest that the Ecklonia canopy may positively influence the presence of sponge species such as Crella incrustans; we propose that the canopy may allow its coexistence with turf algae underneath the canopy by altering the light regime and other environmental factors, which may be detrimental for some species. Our results highlight how any loss of canopy-forming species might have negative effects on sponge assemblages, which could affect the energy flow and the overall biodiversity found in these habitats. Copyright © Marine Biological Association of the United Kingdom 2015

Acevedo J.,Centro Regional Of Estudios Del Cuaternario Fuego Patagonia Y Antartica Fundacion Cequa | Mora C.,Centro Regional Of Estudios Del Cuaternario Fuego Patagonia Y Antartica Fundacion Cequa | Aguayo-Lobo A.,Instituto Antartico Chileno INACH
Marine Mammal Science | Year: 2014

We investigated sex-related site fidelity by humpback whales to the Fueguian Archipelago, a new feeding area in the eastern South Pacific, by examining the resighting histories of 45 males and 39 females recorded from 2003 to 2012. Results indicated an overall annual return to the feeding area of 74.8%, and annual sex ratio is roughly equal in the population. The probability of an individual being resighted across years and in subsequent years was not significantly different for both males and females, however, the proportion of resighting within a year was significantly higher for individual males compared to females. Potential sources of sex-related bias were analyzed, but none were found to be significant. Greater intraannual resighting frequency for males may reflect sex-based differences in spatial occupation and short-range movements due to potential differences in energy budgets. © 2013 Society for Marine Mammalogy.

Cardenas C.A.,University of Magallanes | Cardenas C.A.,Instituto Antartico Chileno INACH | Montiel A.,University of Magallanes
Polar Biology | Year: 2015

Previous studies from other latitudes have demonstrated that depth and spatial heterogeneity, produced by surface inclination, can have strong effects on diversity and distribution of sessile assemblages on rocky reefs. Rocky reef communities in the subantarctic Magellan region have been rarely studied, and the factors influencing diversity, distribution and abundance of benthic communities remain poorly understood. Sessile benthic assemblages inhabiting rocky reefs habitats were studied by SCUBA diving at Punta Santa Ana, Magellan Strait from 0 to 30 m water depth. We describe the sessile assemblages assessing the effect of depth, inclination and other environmental factors on species richness and community structure. A total of 37 taxa of invertebrates and 31 taxa of macroalgae were identified based on 280 high-resolution photoquadrats. Species richness and percent coverage varied with depth and inclination. Macroalgae dominated in abundance in the shallows, while bryozoans and ascidians (mound and tree-like forms) increased their coverage with depth. Lithothamnion sp. dominated on vertical and inclined surfaces while sheet-like organism such as bryozoans increased their coverage on overhanging surfaces. Multivariate analyses showed that sessile assemblages at Punta Santa Ana are strongly influenced by the interaction between inclination and depth, which alter the effect of other physical factors such as light and sedimentation. In this regard, our results suggest that sedimentation may play a role structuring benthic assemblages in Punta Santa Ana, especially in deeper zones, where it may replace the structuring effect produced by light in the shallows. © 2015, Springer-Verlag Berlin Heidelberg.

Matus R.,Natura Patagonia | Droguett D.,Wildlife Conservation Society | Vila A.,Wildlife Conservation Society | Aguayo-Lobo A.,Instituto Antartico Chileno INACH | Torres D.,Pedro de Valdivia University
Polar Biology | Year: 2011

The Antarctic fur seal, Arctocephalus gazella, in the eastern South Pacific Ocean, first reported on Hoste Island, Cape Horn in 1973, and then on the Juan Fernandez Archipelago in 1982 and 1983, was recorded again in October and December 2009 on the southern coast of Chile. Three different individuals were seen simultaneously on a single day at Punta Dungenes, Magellan Strait, and a fourth individual was sighted at the northeastern coast of Almirantazgo Sound, Tierra del Fuego. These records represent the first sightings of live Arctocephalus gazella in southern Chile. Although it is difficult to establish both their origin and rationale for dispersion outside of their distribution range, the substantial breeding population recovery in South Georgia and food shortages during the breeding and post-breeding season are suggested as possible explanations. © 2011 Springer-Verlag.

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