Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013
We summarize diversity, group size and habitat of cetaceans documented through ship-based visual survey effort (13,694 km; 1163.5 h) off NW Africa (Conakry to Tangier) in spring and fall of 2011-2013. Study area covered mainly continental shelf with some slope waters. Platform-of-opportunity surveyi...
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ftoceandocs:oai:aquadocs.org:1834/9195 2023-05-15T17:10:52+02:00 Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 Cetaceans in coastal waters of Northwest Africa Oceanographic and biological features in the Canary Current Large Marine Ecosystem. Djiba, Abdoulaye Bamy, Idrissa Lamine Samba Ould Bilal, Abdellahi Van Waerebeek, Koen Valdés, Luis Déniz-González, Itahisa Northwest Africa Canary Current 2015 pp. 283-297 http://hdl.handle.net/1834/9195 en eng IOC-UNESCO Paris, France Intergovernmental Oceanographic Commission, Technical Series: 115; http://www.unesco.org/new/en/ioc/ts115 http://hdl.handle.net/1834/9195 Cetacean diversity Relative abundance Group size Population identity CCLME ASFA15::H::Habitat Report Section Refereed 2015 ftoceandocs 2023-04-06T17:01:02Z We summarize diversity, group size and habitat of cetaceans documented through ship-based visual survey effort (13,694 km; 1163.5 h) off NW Africa (Conakry to Tangier) in spring and fall of 2011-2013. Study area covered mainly continental shelf with some slope waters. Platform-of-opportunity surveying yielded 270 primary sightings of 14 species. Due to passing mode, 35.7% were identifiable only to family/category: unidentified Delphinidae (25.0%), unidentified rorquals (5.88%) and unidentified whales (4.78%). Delphinus delphis predominated with 28.7% of total sightings (32.7%, including probable) and a massive 71.3% (76.5%) of total number of cetaceans observed (n=15,595). Encounter rate was 81.2 common dolphins 100 km-1; mean group size 124.92. Tursiops truncatus, primarily inshore ecotype (median depth, 44.5 m), accounted for 9.56% (11.4%) of sightings and 1.35% (1.83%) of total cetaceans. Megaptera novaeangliae (6.25%) was regularly seen south of Dakar with a Southern Hemisphere seasonality. Other species showed a relatively low % occurrence: Globicephala spp. (2.57), Orcinus orca (1.10), Grampus griseus (0.73), Stenella frontalis (1.84), S. attenuata (0.37), S. clymene (0.37), S. coeruleoalba (0.37), Balaenoptera brydei (1.10), B. musculus (0.37), beaked whale (0.37), probable-B. borealis (0.37). Baleen plates recovered from a bottom-trawl also evidenced B. borealis presence. Seven new range state records included: G. griseus, S. coeruleoalba (Atlantic Morocco), O. orca, B. musculus (The Gambia), G. macrorhynchus, S. frontalis (Guinea-Bissau), S. attenuata (Guinea). Published Book Megaptera novaeangliae Orca Orcinus orca IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
institution |
Open Polar |
collection |
IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications |
op_collection_id |
ftoceandocs |
language |
English |
topic |
Cetacean diversity Relative abundance Group size Population identity CCLME ASFA15::H::Habitat |
spellingShingle |
Cetacean diversity Relative abundance Group size Population identity CCLME ASFA15::H::Habitat Djiba, Abdoulaye Bamy, Idrissa Lamine Samba Ould Bilal, Abdellahi Van Waerebeek, Koen Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
topic_facet |
Cetacean diversity Relative abundance Group size Population identity CCLME ASFA15::H::Habitat |
description |
We summarize diversity, group size and habitat of cetaceans documented through ship-based visual survey effort (13,694 km; 1163.5 h) off NW Africa (Conakry to Tangier) in spring and fall of 2011-2013. Study area covered mainly continental shelf with some slope waters. Platform-of-opportunity surveying yielded 270 primary sightings of 14 species. Due to passing mode, 35.7% were identifiable only to family/category: unidentified Delphinidae (25.0%), unidentified rorquals (5.88%) and unidentified whales (4.78%). Delphinus delphis predominated with 28.7% of total sightings (32.7%, including probable) and a massive 71.3% (76.5%) of total number of cetaceans observed (n=15,595). Encounter rate was 81.2 common dolphins 100 km-1; mean group size 124.92. Tursiops truncatus, primarily inshore ecotype (median depth, 44.5 m), accounted for 9.56% (11.4%) of sightings and 1.35% (1.83%) of total cetaceans. Megaptera novaeangliae (6.25%) was regularly seen south of Dakar with a Southern Hemisphere seasonality. Other species showed a relatively low % occurrence: Globicephala spp. (2.57), Orcinus orca (1.10), Grampus griseus (0.73), Stenella frontalis (1.84), S. attenuata (0.37), S. clymene (0.37), S. coeruleoalba (0.37), Balaenoptera brydei (1.10), B. musculus (0.37), beaked whale (0.37), probable-B. borealis (0.37). Baleen plates recovered from a bottom-trawl also evidenced B. borealis presence. Seven new range state records included: G. griseus, S. coeruleoalba (Atlantic Morocco), O. orca, B. musculus (The Gambia), G. macrorhynchus, S. frontalis (Guinea-Bissau), S. attenuata (Guinea). Published |
author2 |
Valdés, Luis Déniz-González, Itahisa |
format |
Book |
author |
Djiba, Abdoulaye Bamy, Idrissa Lamine Samba Ould Bilal, Abdellahi Van Waerebeek, Koen |
author_facet |
Djiba, Abdoulaye Bamy, Idrissa Lamine Samba Ould Bilal, Abdellahi Van Waerebeek, Koen |
author_sort |
Djiba, Abdoulaye |
title |
Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
title_short |
Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
title_full |
Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
title_fullStr |
Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
title_full_unstemmed |
Biodiversity of cetaceans in coastal waters of Northwest Africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
title_sort |
biodiversity of cetaceans in coastal waters of northwest africa: new insights through platform-of-opportunity visual surveying in 2011-2013 |
publisher |
IOC-UNESCO |
publishDate |
2015 |
url |
http://hdl.handle.net/1834/9195 |
op_coverage |
Northwest Africa Canary Current |
genre |
Megaptera novaeangliae Orca Orcinus orca |
genre_facet |
Megaptera novaeangliae Orca Orcinus orca |
op_relation |
Intergovernmental Oceanographic Commission, Technical Series: 115; http://www.unesco.org/new/en/ioc/ts115 http://hdl.handle.net/1834/9195 |
_version_ |
1766067532262801408 |