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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Online Access: | https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 https://doi.org/10.7557/3.2704 |
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ftunitroemsoe:oai:ojs.henry.ub.uit.no:article/2704 2023-05-15T15:36:10+02:00 Distribution and abundance of large whales in Norwegian and adjacent waters based on ship surveys 1995-2001 Øien, Nils 2009-09-01 application/pdf https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 https://doi.org/10.7557/3.2704 eng eng Septentrio Academic Publishing https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704/2553 https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 doi:10.7557/3.2704 Copyright (c) 2009 Nils Øien http://creativecommons.org/licenses/by/3.0/ CC-BY NAMMCO Scientific Publications; Vol 7: North Atlantic Sightings Surveys: Counting whales in the North Atlantic, 1987-2001; 31-47 2309-2491 1560-2206 10.7557/3.7 distribution abundance whales North Atlantic surveys info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2009 ftunitroemsoe https://doi.org/10.7557/3.2704 https://doi.org/10.7557/3.7 2021-08-16T16:37:46Z 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 University of Tromsø: Septentrio Academic Publishing NAMMCO Scientific Publications 7 31 |
institution |
Open Polar |
collection |
University of Tromsø: Septentrio Academic Publishing |
op_collection_id |
ftunitroemsoe |
language |
English |
topic |
distribution abundance whales North Atlantic surveys |
spellingShingle |
distribution abundance whales North Atlantic surveys Øien, Nils 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 |
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 |
Øien, Nils |
author_facet |
Øien, Nils |
author_sort |
Øien, Nils |
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://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 https://doi.org/10.7557/3.2704 |
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: North Atlantic Sightings Surveys: Counting whales in the North Atlantic, 1987-2001; 31-47 2309-2491 1560-2206 10.7557/3.7 |
op_relation |
https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704/2553 https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2704 doi:10.7557/3.2704 |
op_rights |
Copyright (c) 2009 Nils Øien http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.7557/3.2704 https://doi.org/10.7557/3.7 |
container_title |
NAMMCO Scientific Publications |
container_volume |
7 |
container_start_page |
31 |
_version_ |
1766366499506749440 |