A combined stereo-photogrammetry and underwater-video system to study group composition of dolphins
Article
Article Title | A combined stereo-photogrammetry and underwater-video system to study group composition of dolphins |
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ERA Journal ID | 1916 |
Article Category | Article |
Authors | Bräger, Stefan, Chong, Albert, Dawson, Stephen, Slooten, Elisabeth and Würsig, Bernd |
Journal Title | Helgoland Marine Research |
Journal Citation | 53 (2), pp. 122-128 |
Number of Pages | 7 |
Year | 1999 |
ISSN | 0174-3597 |
1438-387X | |
1438-3888 | |
Digital Object Identifier (DOI) | https://doi.org/10.1007/s101520050015 |
Web Address (URL) | https://Germany |
Abstract | One reason for the paucity of knowledge of dolphin social structure is the difficulty of measuring individual dolphins. In Hector's dolphins, Cephalorhynchus hectori, total body length is a function of age, and sex can be determined by individual colouration pattern. We developed a novel system combining stereo-photogrammetry and underwater-video to record dolphin group composition. The system consists of two downward-looking single-lens-reflex (SLR) cameras and a Hi8 video camera in an underwater housing mounted on a small boat. Bow-riding Hector's dolphins were photographed and video-taped at close range in coastal waters around the South Island of New Zealand. Three-dimensional, stereoscopic measurements of the distance between the blowhole and the anterior margin of the dorsal fin (BH-DF) were calibrated by a suspended frame with reference points. Growth functions derived from measurements of 53 dead Hector's dolphins (29 female : 24 male) provided the necessary reference data. For the analysis, the measurements were synchronised with corresponding underwater-video of the genital area. A total of 27 successful measurements (8 with corresponding sex) were obtained, showing how this new system promises to be potentially useful for cetacean studies. |
Keywords | group composition; stereo-photogrammetry; underwater-video; Hector's dolphin; cetaceans |
Public Notes | There are no files associated with this item. |
Byline Affiliations | University of Otago, New Zealand |
Texas A&M University, United States |
https://research.usq.edu.au/item/w2788/a-combined-stereo-photogrammetry-and-underwater-video-system-to-study-group-composition-of-dolphins
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