Historical population size of the threatened New Zealand sea lion Phocarctos hookeri
Marine mammal species were exploited worldwide during periods of commercial sealing in the 18th and 19th centuries. For many of these species, an estimate of the pre-exploitation abundance of the species is lacking, as historical catch records are generally scarce and inaccurate. Genetic estimates o...
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fthighwire:oai:open-archive.highwire.org:jmammal:97/2/436 2023-05-15T15:33:36+02:00 Historical population size of the threatened New Zealand sea lion Phocarctos hookeri Collins, Catherine J. Chilvers, B. Louise Taylor, Matthew Robertson, Bruce C. 2016-03-23 00:00:00.0 text/html http://jmammal.oxfordjournals.org/cgi/content/short/97/2/436 https://doi.org/10.1093/jmammal/gyv187 en eng Oxford University Press http://jmammal.oxfordjournals.org/cgi/content/short/97/2/436 http://dx.doi.org/10.1093/jmammal/gyv187 Copyright (C) 2016, Oxford University Press Feature Article TEXT 2016 fthighwire https://doi.org/10.1093/jmammal/gyv187 2016-11-16T18:42:18Z Marine mammal species were exploited worldwide during periods of commercial sealing in the 18th and 19th centuries. For many of these species, an estimate of the pre-exploitation abundance of the species is lacking, as historical catch records are generally scarce and inaccurate. Genetic estimates of long-term effective population size provide a means to estimate the pre-exploitation abundance. Here, we apply genetic methods to estimate the long-term effective population size of the subantarctic lineage of the New Zealand sea lion (NZ sea lion), Phocarctos hookeri . This species is predominantly restricted to the subantarctic islands, south of mainland New Zealand, following commercial sealing in the 19th century. Today, the population consists of ~9,880 animals and population growth is slow. Auckland Island breeding colonies of NZ sea lion are currently impacted by commercial trawl fisheries via regular sea lion deaths as bycatch. In order to estimate sustainable levels of bycatch, an estimate of the population’s carrying capacity ( K ) is required. We apply the genetically estimated long-term effective population size of NZ sea lions as a proxy for the estimated historical carrying capacity of the subantarctic population. The historical abundance of subantarctic NZ sea lions was significantly higher than the target values of K employed by the contemporary management. The current management strategy may allow unsustainable bycatch levels, thereby limiting the recovery of the NZ sea lion population toward historical carrying capacity. Text Auckland Island HighWire Press (Stanford University) New Zealand Journal of Mammalogy 97 2 436 443 |
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Feature Article |
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Feature Article Collins, Catherine J. Chilvers, B. Louise Taylor, Matthew Robertson, Bruce C. Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
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Feature Article |
description |
Marine mammal species were exploited worldwide during periods of commercial sealing in the 18th and 19th centuries. For many of these species, an estimate of the pre-exploitation abundance of the species is lacking, as historical catch records are generally scarce and inaccurate. Genetic estimates of long-term effective population size provide a means to estimate the pre-exploitation abundance. Here, we apply genetic methods to estimate the long-term effective population size of the subantarctic lineage of the New Zealand sea lion (NZ sea lion), Phocarctos hookeri . This species is predominantly restricted to the subantarctic islands, south of mainland New Zealand, following commercial sealing in the 19th century. Today, the population consists of ~9,880 animals and population growth is slow. Auckland Island breeding colonies of NZ sea lion are currently impacted by commercial trawl fisheries via regular sea lion deaths as bycatch. In order to estimate sustainable levels of bycatch, an estimate of the population’s carrying capacity ( K ) is required. We apply the genetically estimated long-term effective population size of NZ sea lions as a proxy for the estimated historical carrying capacity of the subantarctic population. The historical abundance of subantarctic NZ sea lions was significantly higher than the target values of K employed by the contemporary management. The current management strategy may allow unsustainable bycatch levels, thereby limiting the recovery of the NZ sea lion population toward historical carrying capacity. |
format |
Text |
author |
Collins, Catherine J. Chilvers, B. Louise Taylor, Matthew Robertson, Bruce C. |
author_facet |
Collins, Catherine J. Chilvers, B. Louise Taylor, Matthew Robertson, Bruce C. |
author_sort |
Collins, Catherine J. |
title |
Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
title_short |
Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
title_full |
Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
title_fullStr |
Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
title_full_unstemmed |
Historical population size of the threatened New Zealand sea lion Phocarctos hookeri |
title_sort |
historical population size of the threatened new zealand sea lion phocarctos hookeri |
publisher |
Oxford University Press |
publishDate |
2016 |
url |
http://jmammal.oxfordjournals.org/cgi/content/short/97/2/436 https://doi.org/10.1093/jmammal/gyv187 |
geographic |
New Zealand |
geographic_facet |
New Zealand |
genre |
Auckland Island |
genre_facet |
Auckland Island |
op_relation |
http://jmammal.oxfordjournals.org/cgi/content/short/97/2/436 http://dx.doi.org/10.1093/jmammal/gyv187 |
op_rights |
Copyright (C) 2016, Oxford University Press |
op_doi |
https://doi.org/10.1093/jmammal/gyv187 |
container_title |
Journal of Mammalogy |
container_volume |
97 |
container_issue |
2 |
container_start_page |
436 |
op_container_end_page |
443 |
_version_ |
1766364135114670080 |