Gibbons Escobar, Jorge Eduardo

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Gibbons Escobar, Jorge Eduardo

Afiliación principal

Instituto de la Patagonia

jorge.gibbons@umag.cl

ORCID

0009-0008-0122-7561

Jerarquía académica

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Otra línea emergente

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Mostrando 1 - 6 de 6

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DOI 10.3354/esr00924
Geographic and temporal patterns of non-lethal attacks on humpback whales by killer whales in the eastern South Pacific and the Antarctic Peninsula
2018
Capella, Juan J.
;
Felix, Fernando
;
Florez-Gonzalez, Lilian
;
Gibbons Escobar, Jorge Eduardo
;
Haase, Ben
;
Guzman, Hector M.
The role and impact of killer whales Orcinus orca as predators of baleen whales has been emphasized by studies of humpback whales Megaptera novaeangliae. In this study, rake marks on the fluke were used as a proxy for predatory attacks in a sample of 2909 adult humpback whales and 133 calves from 5 breeding and 2 feeding locations in the eastern South Pacific and the Antarctic Peninsula. The goal of this study was to evaluate how often, at what age, where, and when humpback whales were more susceptible to attacks. Overall, 11.5 % of adults and 19.5 % of calves had rake marks on their flukes. Significant differences were found in the prevalence of scars in calves when comparing breeding (9 %) vs. feeding areas (34 %) (chi(2) = 10.23, p < 0.01). Multi-year sighting analysis of scar acquisition in 120 adults (82 % site fidelity) and 37 calves in the Magellan Strait showed no new marks after the initial sighting for the subsequent 15 yr. This finding indicates that rake marks were most probably acquired when whales were calves, which supports the belief that scar acquisition is a once in a lifetime event. The odds of having rake marks increased with time but with a significantly higher rate in calves (chi(2) = 5.04, p < 0.05), which suggests an increase in predation pressure over time. Our results support the earlier hypothesis that killer whale attacks occur mostly on calves, near breeding sites, and during the first migration to feeding areas.
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DOI 10.3354/esr00924
Geographic and temporal patterns of non-lethal attacks on humpback whales by killer whales in the eastern South Pacific and the Antarctic Peninsula
2018
Capella, Juan J.
;
Felix, Fernando
;
Florez-Gonzalez, Lilian
;
Gibbons Escobar, Jorge Eduardo
;
Haase, Ben
;
Guzman, Hector M.
The role and impact of killer whales Orcinus orca as predators of baleen whales has been emphasized by studies of humpback whales Megaptera novaeangliae. In this study, rake marks on the fluke were used as a proxy for predatory attacks in a sample of 2909 adult humpback whales and 133 calves from 5 breeding and 2 feeding locations in the eastern South Pacific and the Antarctic Peninsula. The goal of this study was to evaluate how often, at what age, where, and when humpback whales were more susceptible to attacks. Overall, 11.5 % of adults and 19.5 % of calves had rake marks on their flukes. Significant differences were found in the prevalence of scars in calves when comparing breeding (9 %) vs. feeding areas (34 %) (chi(2) = 10.23, p < 0.01). Multi-year sighting analysis of scar acquisition in 120 adults (82 % site fidelity) and 37 calves in the Magellan Strait showed no new marks after the initial sighting for the subsequent 15 yr. This finding indicates that rake marks were most probably acquired when whales were calves, which supports the belief that scar acquisition is a once in a lifetime event. The odds of having rake marks increased with time but with a significantly higher rate in calves (chi(2) = 5.04, p < 0.05), which suggests an increase in predation pressure over time. Our results support the earlier hypothesis that killer whale attacks occur mostly on calves, near breeding sites, and during the first migration to feeding areas.
Scopus© Citations 11 4
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DOI 10.3389/fmars.2021.624974
Spatial and Temporal Effects of Whale Watching on a Tourism-Naive Resident Population of Bottlenose Dolphins (Tursiops truncatus) in the Humboldt Penguin National Reserve, Chile
2021-4-23
Toro, Frederick
;
Alarcon, Jaime
;
Toro-Barros, Barbara
;
Mallea, Gabriela
;
Capella, Juan
;
Umaran-Young, Clara
;
Abarca, Paulette
;
Lakestani, Nelly
;
Pena, Claudia
;
Alvarado-Rybak, Mario
Standardized measures of behavior can be powerful tools for assessing the impact of whale watching activities on natural populations of cetaceans. To determine the possible impact of tourism on dolphins between a period without whale watching (1989-1992) (T1) and a period with whale watching (2010-2020) (T2), we examined the changes in the rate of surface behaviors, the group size of long-time resident bottlenose dolphins living in the waters of the Humboldt Current off Chile, and for T2 alone, we compared these differences between two localities, the Punta de Choros and Chanaral de Aceituno coves. We observed a significant decrease in the group size of the resident population and in the frequency of surface events associated with the absence and presence of tourism. For T2, we observed significant differences for the frequency of surface events between the Chanaral de Aceituno and Punta de Choros coves and differences in the frequency of surface events at different hours of the day. This was associated with the number of vessels at the time of the encounter. In addition, we observed for T2 that the most observed instantaneous response of the dolphins to the presence of tourist vessels was to avoid the boats, while approaching the boats was the least observed response. The number of vessels present in each dolphin encounter was the most important variable for our model as it explains these differences. These results show that tourism vessels have a significant impact on dolphin behavior and sociability, while the same population of dolphins have different spatial and temporal responses to different impacts of tourism. Further studies are needed to establish whether changes in the rate of surface behaviors are associated with higher levels of stress in dolphins and with effects on their health and reproductive success in the long term.
Scopus© Citations 7 1
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DOI 10.1016/j.anbehav.2018.03.009
Home sweet home: social dynamics and genetic variation of a long-term resident bottlenose dolphin population off the Chilean coast
2018-5
Jose Perez-Alvarez, M.
;
Vasquez, Rodrigo A.
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Moraga, Rodrigo
;
Santos-Carvallo, Macarena
;
Kraft, Sebastian
;
Sabaj, Valeria
;
Capella, Juan
;
Gibbons Escobar, Jorge Eduardo
;
Vilina, Yerko
;
Poulin, Elie
Coastal resident and pelagic nonresident bottlenose dolphins, Tursiops truncatus, have been described in north-central Chile. Using long-term residence data (over 13 years of photo-identification) and genetic mtDNA information, we analysed the social dynamics through time and the genetic variation of this long-term resident population, and evaluated its sociogenetic interaction with nonresidents. Pelagic nonresident dolphins exhibited a higher level of genetic diversity than coastal residents and a significant difference in genetic structure was detected between them. Based on the difference in haplotype numbers and frequencies between resident and nonresident populations and between resident males and females, we propose a population dynamic model in which the resident population is composed of (1) resident females (founder lineages) and some of their female descendants that were born in and remained in the group, without effective female immigration from the nonresident population, (2) resident male descendants of the founder lineage that were born in and remained in the group and (3) resident males that were incorporated from the pelagic groups. Male-biased migration from nonresident pelagic groups into the resident population likely contributes to genetic variation and therefore may help limit inbreeding in the resident population. Finally, we propose that the peripatric model of population differentiation, where resident groups are sporadically connected to the pelagic population, may explain the origin of this unique resident population of bottlenose dolphins along the Chilean coast. (c) 2018 The Authors. Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
Scopus© Citations 6 1
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DOI 10.1080/15564894.2019.1643429
A Novel Child Burial from Tierra del Fuego: A Preliminary Report
2020-7-2
Prieto, Alfredo
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Morano Buchner, Susana Javiera
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Cardenas, Pedro
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Sierpe Gonzalez, Victor Manuel
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Calas, Elisa
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Christensen, Marianne
;
Lefevre, Christine
;
Laroulandie, Veronique
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Espinosa-Parrilla, Yolanda
;
Ramirez, Oscar
This paper reports the archaeological materials from a unique child burial recently discovered in Tierra del Fuego. Preliminary analyses are consistent with the idea that the burial belongs to the Selk'nam culture. Although the Selk'nam archaeological record is abundant, very little is known about their mortuary practices. In this well-preserved burial, the human remains were accompanied by an unusual set of grave goods, which have not been described in the archaeological literature for this region. Radiocarbon dating places this burial at the beginning of the Post-Columbian period in Tierra del Fuego (331-499 cal BP). Analyses presented herein include information on the sex, diet, and genetics of the child, which provided the first genetic evidence for the presence of mitochondrial sub-haplogroup D1g5 in the Selk'nam population in Tierra de Fuego. We also provide a detailed description of the cultural materials, which include mammal and bird bones and lithic material. This is a unique find because it possesses a wealth of archaeological materials that are previously unknown in the region.
Scopus© Citations 6 3
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DOI 10.1016/j.marpol.2020.103990
Humpback whale movements in a narrow and heavily-used shipping passage, Chile
2020-8
Guzman, Hector M.
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Capella, Juan J.
;
Valladares, Carlos
;
Gibbons Escobar, Jorge Eduardo
;
Condit, Richard
The Magellan Strait is a narrow passage connecting the Pacific and Atlantic oceans in South America. An average of 2023 ships per year transit this corridor with 80% representing the international fleet. The southwestern part of the Strait in Chile is an important summer feeding area for humpback whales. Considering the risk to whales of feeding among dense ship traffic, the movements of 25 satellite-tagged whales relative to vessel density were analyzed, to provide policy recommendations for protecting the species from vessel collisions. A total of 3694 filtered whale positions from 21 individuals were obtained along the southwest passage. The daily range covered by individual whales was 8.8 km, and <25 km on 90% of all days. Ship density in the same square kilometers where whales were encountered was 0.27 per week, slightly more often than once per month, however this encounter rate varied by 100-fold between individuals, depending on how often animals were in the central shipping lane. One of the tagged whales stopped transmitting and washed up dead suggesting a ship strike. In the last decade, four other humpback whales and three sei whales were killed by probable ship strikes, all near Isla Carlos III, the core of the humpback feeding area. A 10-knot speed restriction and onboard observers are recommended during the five months of maximum whale abundance, applying to all merchant vessels traveling through the Strait, between Cabo Holland and Isla Bonete north of Carlos III Island, for a distance of 28 nautical miles (52 km).
Scopus© Citations 8 1

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