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 | 
|---|---|
| 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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