Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia
Estimates of the abundance of breeding group ‘D’ humpback whales (Megaptera novaeangliae) are key to managing what is thought to be one of the largest populations of the species. Five years (2000, 2001, 2006, 2007, and 2008) of aerial surveys carried out over an eight-year period at North West Cape...
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ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/006aab8a-72f5-4e34-861b-a372998f240a 2023-05-15T16:35:59+02:00 Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia Salgado Kent, Chandra Jenner, Curt Jenner, Micheline Bouchet, Philippe Rexstad, Eric 2012 https://risweb.st-andrews.ac.uk/portal/en/researchoutput/southern-hemisphere-breeding-stock-d-humpback-whale-population-estimates-from-north-west-cape-western-australia(006aab8a-72f5-4e34-861b-a372998f240a).html eng eng info:eu-repo/semantics/restrictedAccess Salgado Kent , C , Jenner , C , Jenner , M , Bouchet , P & Rexstad , E 2012 , ' Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia ' , Journal of Cetacean Research and Management , vol. 12 , no. 1 , pp. 29-38 . article 2012 ftunstandrewcris 2021-12-26T14:19:09Z Estimates of the abundance of breeding group ‘D’ humpback whales (Megaptera novaeangliae) are key to managing what is thought to be one of the largest populations of the species. Five years (2000, 2001, 2006, 2007, and 2008) of aerial surveys carried out over an eight-year period at North West Cape (NWC, Western Australia) using line transect methodology allowed trends in whale numbers to be investigated, and provided a base for comparison with estimates made approximately 400km south at Shark Bay (SB, Western Australia). A total of 3,127 whale detections were made during 74 surveys of the 7,043km2 study area west of NWC. Pod abundance for each flight was computed using a Horvitz-Thompson like estimator and converted to an absolute measure of population size after corrections were made for estimated mean cluster size, unsurveyed time, swimming speed and animal availability. Resulting estimates from the migration model of best fit with the most credible assumptions were 7,276 (CI = 4,993-10,167) for 2000, 12,280 (CI = 6,830-49,434) for 2001, 18,692 (CI = 12,980-24,477) for 2006, 20,044 (CI = 13,815-31,646) for 2007, and 26,100 (CI = 20,152-33,272) for 2008. Based on these data, the trend model with the greatest r2 was exponential with an annual increase rate of 13% (CI=5.6%-18.1%). While this value is above the species’ maximum plausible growth rate of 11.8%, it is reasonably close to previous reports of between 10-12%. The coefficient of variation, however, was too large for a reliable trend estimate. Perception bias was also not accounted for in these calculations. Based on a crude appraisal which yielded an estimated p(0) of 0.783 (0from independent observer effort, CV=0.973), the 2008 humpback population size could then be as large as 33,333. In conclusion, the work here provides evidence of an increasing breeding group ‘D’ humpback whale population, however more surveys are necessary to confirm whether the population is indeed increasing at its maximum rate Article in Journal/Newspaper Humpback Whale Megaptera novaeangliae University of St Andrews: Research Portal West Cape ENVELOPE(73.283,73.283,-53.033,-53.033) |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
description |
Estimates of the abundance of breeding group ‘D’ humpback whales (Megaptera novaeangliae) are key to managing what is thought to be one of the largest populations of the species. Five years (2000, 2001, 2006, 2007, and 2008) of aerial surveys carried out over an eight-year period at North West Cape (NWC, Western Australia) using line transect methodology allowed trends in whale numbers to be investigated, and provided a base for comparison with estimates made approximately 400km south at Shark Bay (SB, Western Australia). A total of 3,127 whale detections were made during 74 surveys of the 7,043km2 study area west of NWC. Pod abundance for each flight was computed using a Horvitz-Thompson like estimator and converted to an absolute measure of population size after corrections were made for estimated mean cluster size, unsurveyed time, swimming speed and animal availability. Resulting estimates from the migration model of best fit with the most credible assumptions were 7,276 (CI = 4,993-10,167) for 2000, 12,280 (CI = 6,830-49,434) for 2001, 18,692 (CI = 12,980-24,477) for 2006, 20,044 (CI = 13,815-31,646) for 2007, and 26,100 (CI = 20,152-33,272) for 2008. Based on these data, the trend model with the greatest r2 was exponential with an annual increase rate of 13% (CI=5.6%-18.1%). While this value is above the species’ maximum plausible growth rate of 11.8%, it is reasonably close to previous reports of between 10-12%. The coefficient of variation, however, was too large for a reliable trend estimate. Perception bias was also not accounted for in these calculations. Based on a crude appraisal which yielded an estimated p(0) of 0.783 (0from independent observer effort, CV=0.973), the 2008 humpback population size could then be as large as 33,333. In conclusion, the work here provides evidence of an increasing breeding group ‘D’ humpback whale population, however more surveys are necessary to confirm whether the population is indeed increasing at its maximum rate |
format |
Article in Journal/Newspaper |
author |
Salgado Kent, Chandra Jenner, Curt Jenner, Micheline Bouchet, Philippe Rexstad, Eric |
spellingShingle |
Salgado Kent, Chandra Jenner, Curt Jenner, Micheline Bouchet, Philippe Rexstad, Eric Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
author_facet |
Salgado Kent, Chandra Jenner, Curt Jenner, Micheline Bouchet, Philippe Rexstad, Eric |
author_sort |
Salgado Kent, Chandra |
title |
Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
title_short |
Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
title_full |
Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
title_fullStr |
Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
title_full_unstemmed |
Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia |
title_sort |
southern hemisphere breeding stock 'd' humpback whale population estimates from north west cape, western australia |
publishDate |
2012 |
url |
https://risweb.st-andrews.ac.uk/portal/en/researchoutput/southern-hemisphere-breeding-stock-d-humpback-whale-population-estimates-from-north-west-cape-western-australia(006aab8a-72f5-4e34-861b-a372998f240a).html |
long_lat |
ENVELOPE(73.283,73.283,-53.033,-53.033) |
geographic |
West Cape |
geographic_facet |
West Cape |
genre |
Humpback Whale Megaptera novaeangliae |
genre_facet |
Humpback Whale Megaptera novaeangliae |
op_source |
Salgado Kent , C , Jenner , C , Jenner , M , Bouchet , P & Rexstad , E 2012 , ' Southern Hemisphere breeding stock 'D' humpback whale population estimates from North West Cape, Western Australia ' , Journal of Cetacean Research and Management , vol. 12 , no. 1 , pp. 29-38 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1766026294076637184 |