Whales from space: counting southern right whales by satellite

Fretwell, Peter T. ORCID: https://orcid.org/0000-0002-1988-5844; Staniland, Iain J. ORCID: https://orcid.org/0000-0003-2736-9134; Forcada, Jaume ORCID: https://orcid.org/0000-0002-2115-0150. 2014 Whales from space: counting southern right whales by satellite. PLoS One, 9 (2). 10.1371/journal.pone.0088655

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Abstract/Summary

We describe a method of identifying and counting whales using very high resolution satellite imagery through the example of southern right whales breeding in part of the Golfo Nuevo, Península Valdés in Argentina. Southern right whales have been extensively hunted over the last 300 years and although numbers have recovered from near extinction in the early 20th century, current populations are fragmented and are estimated at only a small fraction of pre-hunting total. Recent extreme right whale calf mortality events at Península Valdés, which constitutes the largest single population, have raised fresh concern for the future of the species. The WorldView2 satellite has a maximum 50 cm resolution and a water penetrating coastal band in the far-blue part of the spectrum that allows it to see deeper into the water column. Using an image covering 113 km2, we identified 55 probable whales and 23 other features that are possibly whales, with a further 13 objects that are only detected by the coastal band. Comparison of a number of classification techniques, to automatically detect whale-like objects, showed that a simple thresholding technique of the panchromatic and coastal band delivered the best results. This is the first successful study using satellite imagery to count whales; a pragmatic, transferable method using this rapidly advancing technology that has major implications for future surveys of cetacean populations.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1371/journal.pone.0088655
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ecosystems BAS Programmes > Other
ISSN:	1932-6203
Date made live:	13 Feb 2014 09:58 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/503330

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1371/journal.pone.0088655

Programmes:

BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ecosystems
BAS Programmes > Other

ISSN:

1932-6203

Date made live:

13 Feb 2014 09:58 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/503330