The abundance of blue whales on the Madagascar Plateau, December 1996

 

Show simple item record

dc.contributor.author Best, Peter B
dc.contributor.author Rademeyer, Rebecca A
dc.contributor.author Burton, Chris
dc.contributor.author Ljungblad, Don
dc.contributor.author Sekiguchi, Keiko
dc.contributor.author Shimada, Hiroyuki
dc.contributor.author Thiele, Deborah
dc.contributor.author Reeb, Desray
dc.contributor.author Butterworth, Doug S
dc.date.accessioned 2016-02-26T08:28:07Z
dc.date.available 2016-02-26T08:28:07Z
dc.date.issued 2003
dc.identifier.citation Best, P. B., Rademeyer, R. A., Burton, C., Ljungblad, D., Sekiguchi, K., Shimada, H., ... & Butterworth, D. S. (2003). The abundance of blue whales on the Madagascar Plateau, December 1996. Journal of Cetacean Research and Management, 5(3), 253-260. en_ZA
dc.identifier.issn 1561-0713 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/17294
dc.description.abstract As part of the International Whaling Commission’s SOWER blue whale research programme, two sighting vessels, the Shonan Maru and the Shonan Maru No.2 , surveyed the Madagascar Plateau between 25° and 35°S, 40° and 45°E, in December 1996. A total of 95 sightings of 110 blue whales (assigned in the field as pygmy blue whales – see discussion), 14 sightings of 21 blue whales (subspecies un determined) and 12 sightings of 13 ‘like blue’ whales was made in 23 days. In the first half of the survey, the whole research area was cov ered in a mainly pre-determined zigzag search pattern, and the associated sightings and effort have been used to derive density estimates for bl ue whales for the area. Sightings in the second half of the survey, where effort was directed at blue whale concentrations, have only bee n used to provide supplementary data for calculation of the effective search half-width and mean school size. The resulting population es timate is 424 (CV = 0.42), or 472 (CV = 0.48) whales when ‘like blue’ sightings are included. Dive times and surfacing behaviour recorded in just over 21h of monitoring suggest that the assumption that all groups on the trackline were seen ( g (0) = 1) is reasonable. As the geographical extent of the survey area was substantially less than that of past catches of blue whales in the region in December, this estim ate must refer to only a portion (possibly about one third) of the total population. Some evidence of feeding on euphausiids in the region was detected, possibly as a consequence of a localised upwelling cell at the southern tip of Madagascar en_ZA
dc.language eng en_ZA
dc.publisher International Whaling Commission en_ZA
dc.source Journal of Cetacean Research and Management en_ZA
dc.source.uri https://iwc.int/jcrm
dc.subject.other Blue whales
dc.title The abundance of blue whales on the Madagascar Plateau, December 1996 en_ZA
dc.type Journal Article en_ZA
dc.date.updated 2016-02-24T12:52:52Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
uct.subject.keywords abundance estimate en_ZA
uct.subject.keywords blue whale en_ZA
uct.subject.keywords Indian ocean en_ZA
uct.subject.keywords line transect en_ZA
uct.subject.keywords respiration en_ZA
uct.subject.keywords feeding en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Resource Assessment and Management Group en_ZA
uct.type.filetype
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Best, P. B., Rademeyer, R. A., Burton, C., Ljungblad, D., Sekiguchi, K., Shimada, H., ... Butterworth, D. S. (2003). The abundance of blue whales on the Madagascar Plateau, December 1996. <i>Journal of Cetacean Research and Management</i>, http://hdl.handle.net/11427/17294 en_ZA
dc.identifier.chicagocitation Best, Peter B, Rebecca A Rademeyer, Chris Burton, Don Ljungblad, Keiko Sekiguchi, Hiroyuki Shimada, Deborah Thiele, Desray Reeb, and Doug S Butterworth "The abundance of blue whales on the Madagascar Plateau, December 1996." <i>Journal of Cetacean Research and Management</i> (2003) http://hdl.handle.net/11427/17294 en_ZA
dc.identifier.vancouvercitation Best PB, Rademeyer RA, Burton C, Ljungblad D, Sekiguchi K, Shimada H, et al. The abundance of blue whales on the Madagascar Plateau, December 1996. Journal of Cetacean Research and Management. 2003; http://hdl.handle.net/11427/17294. en_ZA
dc.identifier.ris TY - Journal Article AU - Best, Peter B AU - Rademeyer, Rebecca A AU - Burton, Chris AU - Ljungblad, Don AU - Sekiguchi, Keiko AU - Shimada, Hiroyuki AU - Thiele, Deborah AU - Reeb, Desray AU - Butterworth, Doug S AB - As part of the International Whaling Commission’s SOWER blue whale research programme, two sighting vessels, the Shonan Maru and the Shonan Maru No.2 , surveyed the Madagascar Plateau between 25° and 35°S, 40° and 45°E, in December 1996. A total of 95 sightings of 110 blue whales (assigned in the field as pygmy blue whales – see discussion), 14 sightings of 21 blue whales (subspecies un determined) and 12 sightings of 13 ‘like blue’ whales was made in 23 days. In the first half of the survey, the whole research area was cov ered in a mainly pre-determined zigzag search pattern, and the associated sightings and effort have been used to derive density estimates for bl ue whales for the area. Sightings in the second half of the survey, where effort was directed at blue whale concentrations, have only bee n used to provide supplementary data for calculation of the effective search half-width and mean school size. The resulting population es timate is 424 (CV = 0.42), or 472 (CV = 0.48) whales when ‘like blue’ sightings are included. Dive times and surfacing behaviour recorded in just over 21h of monitoring suggest that the assumption that all groups on the trackline were seen ( g (0) = 1) is reasonable. As the geographical extent of the survey area was substantially less than that of past catches of blue whales in the region in December, this estim ate must refer to only a portion (possibly about one third) of the total population. Some evidence of feeding on euphausiids in the region was detected, possibly as a consequence of a localised upwelling cell at the southern tip of Madagascar DA - 2003 DB - OpenUCT DP - University of Cape Town J1 - Journal of Cetacean Research and Management LK - https://open.uct.ac.za PB - University of Cape Town PY - 2003 SM - 1561-0713 T1 - The abundance of blue whales on the Madagascar Plateau, December 1996 TI - The abundance of blue whales on the Madagascar Plateau, December 1996 UR - http://hdl.handle.net/11427/17294 ER - en_ZA


Files in this item

This item appears in the following Collection(s)

Show simple item record