Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001
The abundances of large whale species are presented for the northeast Atlantic from near-complete survey coverage in 1995 and from multiple partial-area surveys during 1996-2001. These Norwegian shipboard surveys were generally conducted with 2 independent observer platforms, except for single-platf...
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Septentrio Academic Publishing
2009
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ftdoajarticles:oai:doaj.org/article:7fb5719f168f43fba4f5ff0e9e0e000e 2023-05-15T15:36:10+02:00 Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 Nils Øien 2009-09-01T00:00:00Z https://doi.org/10.7557/3.2704 https://doaj.org/article/7fb5719f168f43fba4f5ff0e9e0e000e EN eng Septentrio Academic Publishing https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 https://doaj.org/toc/1560-2206 https://doaj.org/toc/2309-2491 1560-2206 2309-2491 doi:10.7557/3.2704 https://doaj.org/article/7fb5719f168f43fba4f5ff0e9e0e000e NAMMCO Scientific Publications, Vol 7, Iss 0, Pp 31-47 (2009) distribution abundance whales North Atlantic surveys Ecology QH540-549.5 article 2009 ftdoajarticles https://doi.org/10.7557/3.2704 2022-12-31T01:06:39Z The abundances of large whale species are presented for the northeast Atlantic from near-complete survey coverage in 1995 and from multiple partial-area surveys during 1996-2001. These Norwegian shipboard surveys were generally conducted with 2 independent observer platforms, except for single-platform surveys during part of 1995. Tracking procedures implemented for minke whales – Balaenoptera acutorostrata (the target species) meant that the surveys had to be conducted in passing mode, and there were therefore only limited opportunities for closing on sightings to determine species identity and school size. Abundance estimates for large whale species (fin – Balaenoptera physalus, humpback – Megaptera novaeangliae and sperm whales – Physeter macrocephalus) were obtained by combining sightings from both platforms, and applying standard distance sampling techniques to the smeared and truncated perpendicular distances for each species. Abundance estimates for the 2 survey groupings (1995 and 1996-2001) summarised over comparable areas were: fin whales, 5,034 (cv 0.209) and 6,409 (cv 0.18); humpback whales, 1,059 (cv 0.248) and 1,450 (cv 0.29); and sperm whales, 4,319 (cv 0.199) and 6,207 (cv 0.22). The estimated cv’s are likely underestimates and specifically the combined partial-area survey cv’s do not include additional variance due to possible distributional shifts between years. Inclusion of a new survey stratum north of Iceland (block NVS) in the later set of surveys revealed a high additional abundance there of fin whales 3,960 (cv 0.538) and humpback whales 3,246 (cv 0.512). The high humpback whale estimate for this stratum confirms the Icelandic survey findings of a large humpback whale population summering in that area. Article in Journal/Newspaper Balaenoptera acutorostrata Balaenoptera physalus Humpback Whale Iceland Megaptera novaeangliae North Atlantic Northeast Atlantic Physeter macrocephalus Directory of Open Access Journals: DOAJ Articles NAMMCO Scientific Publications 7 31 |
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Directory of Open Access Journals: DOAJ Articles |
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language |
English |
topic |
distribution abundance whales North Atlantic surveys Ecology QH540-549.5 |
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distribution abundance whales North Atlantic surveys Ecology QH540-549.5 Nils Øien Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
topic_facet |
distribution abundance whales North Atlantic surveys Ecology QH540-549.5 |
description |
The abundances of large whale species are presented for the northeast Atlantic from near-complete survey coverage in 1995 and from multiple partial-area surveys during 1996-2001. These Norwegian shipboard surveys were generally conducted with 2 independent observer platforms, except for single-platform surveys during part of 1995. Tracking procedures implemented for minke whales – Balaenoptera acutorostrata (the target species) meant that the surveys had to be conducted in passing mode, and there were therefore only limited opportunities for closing on sightings to determine species identity and school size. Abundance estimates for large whale species (fin – Balaenoptera physalus, humpback – Megaptera novaeangliae and sperm whales – Physeter macrocephalus) were obtained by combining sightings from both platforms, and applying standard distance sampling techniques to the smeared and truncated perpendicular distances for each species. Abundance estimates for the 2 survey groupings (1995 and 1996-2001) summarised over comparable areas were: fin whales, 5,034 (cv 0.209) and 6,409 (cv 0.18); humpback whales, 1,059 (cv 0.248) and 1,450 (cv 0.29); and sperm whales, 4,319 (cv 0.199) and 6,207 (cv 0.22). The estimated cv’s are likely underestimates and specifically the combined partial-area survey cv’s do not include additional variance due to possible distributional shifts between years. Inclusion of a new survey stratum north of Iceland (block NVS) in the later set of surveys revealed a high additional abundance there of fin whales 3,960 (cv 0.538) and humpback whales 3,246 (cv 0.512). The high humpback whale estimate for this stratum confirms the Icelandic survey findings of a large humpback whale population summering in that area. |
format |
Article in Journal/Newspaper |
author |
Nils Øien |
author_facet |
Nils Øien |
author_sort |
Nils Øien |
title |
Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
title_short |
Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
title_full |
Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
title_fullStr |
Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
title_full_unstemmed |
Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 |
title_sort |
distribution and abundance of large whales in norwegian and adjacent waters based on ship surveys 1995-2001 |
publisher |
Septentrio Academic Publishing |
publishDate |
2009 |
url |
https://doi.org/10.7557/3.2704 https://doaj.org/article/7fb5719f168f43fba4f5ff0e9e0e000e |
genre |
Balaenoptera acutorostrata Balaenoptera physalus Humpback Whale Iceland Megaptera novaeangliae North Atlantic Northeast Atlantic Physeter macrocephalus |
genre_facet |
Balaenoptera acutorostrata Balaenoptera physalus Humpback Whale Iceland Megaptera novaeangliae North Atlantic Northeast Atlantic Physeter macrocephalus |
op_source |
NAMMCO Scientific Publications, Vol 7, Iss 0, Pp 31-47 (2009) |
op_relation |
https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 https://doaj.org/toc/1560-2206 https://doaj.org/toc/2309-2491 1560-2206 2309-2491 doi:10.7557/3.2704 https://doaj.org/article/7fb5719f168f43fba4f5ff0e9e0e000e |
op_doi |
https://doi.org/10.7557/3.2704 |
container_title |
NAMMCO Scientific Publications |
container_volume |
7 |
container_start_page |
31 |
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1766366504014577664 |