Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction
Killer whales are the oceans' apex predators and their potential effects on ecosystems have been demonstrated. In the Southern Ocean, the role of killer whale predation in population declines of southern elephant seals remains largely speculative. We aimed to assess whether top-down control of...
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ftsouthampton:oai:eprints.soton.ac.uk:469007 2023-07-30T03:59:26+02:00 Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction Reisinger, R. R. de Bruyn, P. J.N. Bester, M. N. 2011-09 https://eprints.soton.ac.uk/469007/ English eng Reisinger, R. R., de Bruyn, P. J.N. and Bester, M. N. (2011) Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction. Journal of Zoology, 285 (1), 1-10. (doi:10.1111/j.1469-7998.2011.00815.x <http://dx.doi.org/10.1111/j.1469-7998.2011.00815.x>). Article PeerReviewed 2011 ftsouthampton https://doi.org/10.1111/j.1469-7998.2011.00815.x 2023-07-09T22:54:38Z Killer whales are the oceans' apex predators and their potential effects on ecosystems have been demonstrated. In the Southern Ocean, the role of killer whale predation in population declines of southern elephant seals remains largely speculative. We aimed to assess whether top-down control of pinniped and penguin populations at the Subantarctic Prince Edward Islands (PEIs) is generally plausible using a simple process of elimination. Based on published data, we predicted the energetic ingestion requirements of adult male and female killer whales as 1394 and 1028MJday -1 , respectively. Expanding these requirements to the 37 killer whales photographically identified at the PEIs, the population requires 40600MJday -1 . Based on the energy density and mass data available, we predicted the energy content of available pinniped and penguin prey and calculated the rates at which killer whales would consume these prey in various scenarios. Penguins and Subantarctic fur seals are relatively insensitive to killer whale predation owing to their large population sizes (10000-100000s). Conversely, the smaller populations (100-1000s) of Antarctic fur seals and southern elephant seals are sensitive to predation, particularly the latter, as they have a high energy content (c. 2000-9000MJ). Populations of these seals are currently increasing or stable and we conclude that presently killer whale predation is not driving population declines, although they clearly have the potential for the regulation of these smaller populations. Thus, if population sizes were reduced by bottom-up processes, if killer whale diet shifted or if prey availability changed, top-down predation by killer whales could become significant. By eliminating the possibility of some predation scenarios, we are better able to concentrate future efforts on plausible predation effects. Article in Journal/Newspaper Antarc* Antarctic Antarctic Fur Seals Elephant Seals Killer Whale Prince Edward Islands Southern Elephant Seals Southern Ocean Killer whale University of Southampton: e-Prints Soton Antarctic Southern Ocean Journal of Zoology 285 1 1 10 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Killer whales are the oceans' apex predators and their potential effects on ecosystems have been demonstrated. In the Southern Ocean, the role of killer whale predation in population declines of southern elephant seals remains largely speculative. We aimed to assess whether top-down control of pinniped and penguin populations at the Subantarctic Prince Edward Islands (PEIs) is generally plausible using a simple process of elimination. Based on published data, we predicted the energetic ingestion requirements of adult male and female killer whales as 1394 and 1028MJday -1 , respectively. Expanding these requirements to the 37 killer whales photographically identified at the PEIs, the population requires 40600MJday -1 . Based on the energy density and mass data available, we predicted the energy content of available pinniped and penguin prey and calculated the rates at which killer whales would consume these prey in various scenarios. Penguins and Subantarctic fur seals are relatively insensitive to killer whale predation owing to their large population sizes (10000-100000s). Conversely, the smaller populations (100-1000s) of Antarctic fur seals and southern elephant seals are sensitive to predation, particularly the latter, as they have a high energy content (c. 2000-9000MJ). Populations of these seals are currently increasing or stable and we conclude that presently killer whale predation is not driving population declines, although they clearly have the potential for the regulation of these smaller populations. Thus, if population sizes were reduced by bottom-up processes, if killer whale diet shifted or if prey availability changed, top-down predation by killer whales could become significant. By eliminating the possibility of some predation scenarios, we are better able to concentrate future efforts on plausible predation effects. |
format |
Article in Journal/Newspaper |
author |
Reisinger, R. R. de Bruyn, P. J.N. Bester, M. N. |
spellingShingle |
Reisinger, R. R. de Bruyn, P. J.N. Bester, M. N. Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
author_facet |
Reisinger, R. R. de Bruyn, P. J.N. Bester, M. N. |
author_sort |
Reisinger, R. R. |
title |
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
title_short |
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
title_full |
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
title_fullStr |
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
title_full_unstemmed |
Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction |
title_sort |
predatory impact of killer whales on pinniped and penguin populations at the subantarctic prince edward islands: fact and fiction |
publishDate |
2011 |
url |
https://eprints.soton.ac.uk/469007/ |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctic Fur Seals Elephant Seals Killer Whale Prince Edward Islands Southern Elephant Seals Southern Ocean Killer whale |
genre_facet |
Antarc* Antarctic Antarctic Fur Seals Elephant Seals Killer Whale Prince Edward Islands Southern Elephant Seals Southern Ocean Killer whale |
op_relation |
Reisinger, R. R., de Bruyn, P. J.N. and Bester, M. N. (2011) Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: Fact and fiction. Journal of Zoology, 285 (1), 1-10. (doi:10.1111/j.1469-7998.2011.00815.x <http://dx.doi.org/10.1111/j.1469-7998.2011.00815.x>). |
op_doi |
https://doi.org/10.1111/j.1469-7998.2011.00815.x |
container_title |
Journal of Zoology |
container_volume |
285 |
container_issue |
1 |
container_start_page |
1 |
op_container_end_page |
10 |
_version_ |
1772810252805210112 |