Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island
Killer whales, Orcinus orca , are a cosmopolitan species with large ecological and demographic variation across populations. Population‐specific demographic studies are, therefore, crucial in accurately assessing the status and trends of local killer whale populations. Such studies require long‐term...
Published in: | Wildlife Biology |
---|---|
Main Authors: | , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2020
|
Subjects: | |
Online Access: | http://dx.doi.org/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/pdf/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/full-xml/10.2981/wlb.00732 |
id |
crwiley:10.2981/wlb.00732 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.2981/wlb.00732 2023-12-03T10:25:05+01:00 Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island Jordaan, Rowan K. Oosthuizen, W. Chris Reisinger, Ryan R. Nico De Bruyn, P. J. Mohamed bin Zayed Species Conservation Fund 2020 http://dx.doi.org/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/pdf/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/full-xml/10.2981/wlb.00732 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Wildlife Biology volume 2020, issue 4, page 1-10 ISSN 1903-220X 1903-220X Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics journal-article 2020 crwiley https://doi.org/10.2981/wlb.00732 2023-11-09T14:05:59Z Killer whales, Orcinus orca , are a cosmopolitan species with large ecological and demographic variation across populations. Population‐specific demographic studies are, therefore, crucial in accurately assessing the status and trends of local killer whale populations. Such studies require long‐term datasets and remain scarce, particularly in the Southern Ocean where detailed population specific studies have only been conducted at a single archipelago – Îles Crozet. Here, we analysed 12 years of capture–recapture data (comprising nearly 90 000 identification photographs taken from 2006 to 2018) of killer whales at subantarctic Marion Island (46°54′S, 37°45′E) to estimate the abundance, survival and growth rate of this population. Demographic parameters were estimated using multistate capture recapture models, and Pradel Survival‐Lambda and POPAN single‐state models implemented in the program MARK. Annual survival probability (0.98 [95% CI: 0.96–0.99]) was constant over time, and no important differences between sexes and age‐classes (calves, juveniles, adults) were found. This estimate of survival suggests a life expectancy of approximately 48 years. Realised mean population growth rate (λ) was 1.012 (0.987–1.037) with an estimated population size of 54 (54–60) individuals and a mean calving rate of 0.13 (0.06–0.20) calves born per year per reproductive female. The survival and reproduction rates of killer whales at Marion Island are similar to those of killer whale populations in the eastern North Pacific, Norway and Îles Crozet. However, subtle differences in survival and reproduction rates are present. These are likely the result of local differences in resource abundances, historical impacts on social structure and/or stressors. Also, the presence and scale of fisheries (legal and illegal) in the area may provide opportunities for direct interactions with fishing activities impacting survival and reproduction rates. Article in Journal/Newspaper Îles Crozet Killer Whale Marion Island Orca Orcinus orca Southern Ocean Killer whale Wiley Online Library (via Crossref) Southern Ocean Pacific Norway Lambda ENVELOPE(-62.983,-62.983,-64.300,-64.300) Wildlife Biology 2020 4 1 10 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics Jordaan, Rowan K. Oosthuizen, W. Chris Reisinger, Ryan R. Nico De Bruyn, P. J. Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
topic_facet |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecology, Evolution, Behavior and Systematics |
description |
Killer whales, Orcinus orca , are a cosmopolitan species with large ecological and demographic variation across populations. Population‐specific demographic studies are, therefore, crucial in accurately assessing the status and trends of local killer whale populations. Such studies require long‐term datasets and remain scarce, particularly in the Southern Ocean where detailed population specific studies have only been conducted at a single archipelago – Îles Crozet. Here, we analysed 12 years of capture–recapture data (comprising nearly 90 000 identification photographs taken from 2006 to 2018) of killer whales at subantarctic Marion Island (46°54′S, 37°45′E) to estimate the abundance, survival and growth rate of this population. Demographic parameters were estimated using multistate capture recapture models, and Pradel Survival‐Lambda and POPAN single‐state models implemented in the program MARK. Annual survival probability (0.98 [95% CI: 0.96–0.99]) was constant over time, and no important differences between sexes and age‐classes (calves, juveniles, adults) were found. This estimate of survival suggests a life expectancy of approximately 48 years. Realised mean population growth rate (λ) was 1.012 (0.987–1.037) with an estimated population size of 54 (54–60) individuals and a mean calving rate of 0.13 (0.06–0.20) calves born per year per reproductive female. The survival and reproduction rates of killer whales at Marion Island are similar to those of killer whale populations in the eastern North Pacific, Norway and Îles Crozet. However, subtle differences in survival and reproduction rates are present. These are likely the result of local differences in resource abundances, historical impacts on social structure and/or stressors. Also, the presence and scale of fisheries (legal and illegal) in the area may provide opportunities for direct interactions with fishing activities impacting survival and reproduction rates. |
author2 |
Mohamed bin Zayed Species Conservation Fund |
format |
Article in Journal/Newspaper |
author |
Jordaan, Rowan K. Oosthuizen, W. Chris Reisinger, Ryan R. Nico De Bruyn, P. J. |
author_facet |
Jordaan, Rowan K. Oosthuizen, W. Chris Reisinger, Ryan R. Nico De Bruyn, P. J. |
author_sort |
Jordaan, Rowan K. |
title |
Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
title_short |
Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
title_full |
Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
title_fullStr |
Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
title_full_unstemmed |
Abundance, survival and population growth of killer whales Orcinus orca at subantarctic Marion Island |
title_sort |
abundance, survival and population growth of killer whales orcinus orca at subantarctic marion island |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/pdf/10.2981/wlb.00732 https://onlinelibrary.wiley.com/doi/full-xml/10.2981/wlb.00732 |
long_lat |
ENVELOPE(-62.983,-62.983,-64.300,-64.300) |
geographic |
Southern Ocean Pacific Norway Lambda |
geographic_facet |
Southern Ocean Pacific Norway Lambda |
genre |
Îles Crozet Killer Whale Marion Island Orca Orcinus orca Southern Ocean Killer whale |
genre_facet |
Îles Crozet Killer Whale Marion Island Orca Orcinus orca Southern Ocean Killer whale |
op_source |
Wildlife Biology volume 2020, issue 4, page 1-10 ISSN 1903-220X 1903-220X |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.2981/wlb.00732 |
container_title |
Wildlife Biology |
container_volume |
2020 |
container_issue |
4 |
container_start_page |
1 |
op_container_end_page |
10 |
_version_ |
1784273745608704000 |