A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA
Abstract Knowledge of whale length is important to ecological studies. However, photographic techniques to measure sperm whales traditionally require high vantage points or a complicated stereo system. Furthermore, these traditional techniques require an alongside approach that often prevents indivi...
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crwiley:10.1111/j.1748-7692.2006.00060.x 2023-12-03T10:30:48+01:00 A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA Jaquet, Nathalie 2006 http://dx.doi.org/10.1111/j.1748-7692.2006.00060.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.2006.00060.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.2006.00060.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Marine Mammal Science volume 22, issue 4, page 862-879 ISSN 0824-0469 1748-7692 Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 2006 crwiley https://doi.org/10.1111/j.1748-7692.2006.00060.x 2023-11-09T14:02:25Z Abstract Knowledge of whale length is important to ecological studies. However, photographic techniques to measure sperm whales traditionally require high vantage points or a complicated stereo system. Furthermore, these traditional techniques require an alongside approach that often prevents individual identification. For simple and fast size measurements at sea, I used a laser range finder alongside a digital camera to obtain distance to the fluke at the same time as photo‐identification. The camera/lens and laser range finder were calibrated on objects of known lengths. The coefficient of variation (CV) for test objects was low (CV = 0.21%). Forty‐seven individually identified sperm whales were measured repetitively on up to 12 different occasions, and the CV was lower (CV = 1.3%) than for other photogrammetric techniques (CV = 4.4%–5.1%). A regression of log fluke span to log total length from whaling and stranding data yielded an r 2 of 0.87 (CV of residuals = 6.7%). Thirty‐eight female/immature sperm whales were measured in the Gulf of Mexico (median = 9.3 m, range = 7.1–12.3 m), 167 in the Gulf of California (median = 10.7 m, range = 8.4–13.1 m) and 13 bachelor males off Kaikoura, New Zealand (median = 14.2, range = 11.7–15.8 m). The results were within known sperm whale size and suggested that the population in the Gulf of Mexico was made up of smaller animals than that of the Gulf of California. This technique is easy to implement and allows the measurement of identified individuals. Article in Journal/Newspaper Sperm whale Wiley Online Library (via Crossref) New Zealand Marine Mammal Science 22 4 862 879 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Aquatic Science Ecology, Evolution, Behavior and Systematics Jaquet, Nathalie A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
topic_facet |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
Abstract Knowledge of whale length is important to ecological studies. However, photographic techniques to measure sperm whales traditionally require high vantage points or a complicated stereo system. Furthermore, these traditional techniques require an alongside approach that often prevents individual identification. For simple and fast size measurements at sea, I used a laser range finder alongside a digital camera to obtain distance to the fluke at the same time as photo‐identification. The camera/lens and laser range finder were calibrated on objects of known lengths. The coefficient of variation (CV) for test objects was low (CV = 0.21%). Forty‐seven individually identified sperm whales were measured repetitively on up to 12 different occasions, and the CV was lower (CV = 1.3%) than for other photogrammetric techniques (CV = 4.4%–5.1%). A regression of log fluke span to log total length from whaling and stranding data yielded an r 2 of 0.87 (CV of residuals = 6.7%). Thirty‐eight female/immature sperm whales were measured in the Gulf of Mexico (median = 9.3 m, range = 7.1–12.3 m), 167 in the Gulf of California (median = 10.7 m, range = 8.4–13.1 m) and 13 bachelor males off Kaikoura, New Zealand (median = 14.2, range = 11.7–15.8 m). The results were within known sperm whale size and suggested that the population in the Gulf of Mexico was made up of smaller animals than that of the Gulf of California. This technique is easy to implement and allows the measurement of identified individuals. |
format |
Article in Journal/Newspaper |
author |
Jaquet, Nathalie |
author_facet |
Jaquet, Nathalie |
author_sort |
Jaquet, Nathalie |
title |
A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
title_short |
A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
title_full |
A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
title_fullStr |
A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
title_full_unstemmed |
A SIMPLE PHOTOGRAMMETRIC TECHNIQUE TO MEASURE SPERM WHALES AT SEA |
title_sort |
simple photogrammetric technique to measure sperm whales at sea |
publisher |
Wiley |
publishDate |
2006 |
url |
http://dx.doi.org/10.1111/j.1748-7692.2006.00060.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.2006.00060.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.2006.00060.x |
geographic |
New Zealand |
geographic_facet |
New Zealand |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_source |
Marine Mammal Science volume 22, issue 4, page 862-879 ISSN 0824-0469 1748-7692 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1748-7692.2006.00060.x |
container_title |
Marine Mammal Science |
container_volume |
22 |
container_issue |
4 |
container_start_page |
862 |
op_container_end_page |
879 |
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1784256839916978176 |