Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins
Analysis of animal morphometrics can provide vital information regarding population dynamics, structure, and body condition of cetaceans. Unmanned aerial vehicles (UAVs) have become the primary tool to collect morphometric measurements on whales, whereas on free ranging small dolphins, have not yet...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-12-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/1/21 |
| _version_ | 1827667760506732544 |
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| author | Anna I. Christie Andrew P. Colefax Daniele Cagnazzi |
| author_facet | Anna I. Christie Andrew P. Colefax Daniele Cagnazzi |
| author_sort | Anna I. Christie |
| collection | DOAJ |
| description | Analysis of animal morphometrics can provide vital information regarding population dynamics, structure, and body condition of cetaceans. Unmanned aerial vehicles (UAVs) have become the primary tool to collect morphometric measurements on whales, whereas on free ranging small dolphins, have not yet been applied. This study assesses the feasibility of obtaining reliable body morphometrics from Australian snubfin (<i>Orcaella heinsohni</i>) and humpback dolphins (<i>Sousa sahulensis</i>) using images collected from UAVs. Specifically, using a dolphin replica of known size, we tested the effect of the altitude of the UAV and the position of the animal within the image frame on the accuracy of length estimates. Using linear mixed models, we further assessed the precision of the total length estimates of humpback and snubfin dolphins. The precision of length estimates on the replica increased by ~2% when images were sampled at 45–60 m compared with 15–30 m. However, the precision of total length estimates on dolphins was significantly influenced only by the degree of arch and edge certainty. Overall, we obtained total length estimates with a precision of ~3% and consistent with published data. This study demonstrates the reliability of using UAV based images to obtain morphometrics of small dolphin species, such as snubfin and humpback dolphins. |
| first_indexed | 2024-03-10T03:23:49Z |
| format | Article |
| id | doaj.art-2917882f2934474db7885e0310f4cc44 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T03:23:49Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-2917882f2934474db7885e0310f4cc442023-11-23T12:11:53ZengMDPI AGRemote Sensing2072-42922021-12-011412110.3390/rs14010021Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) DolphinsAnna I. Christie0Andrew P. Colefax1Daniele Cagnazzi2Faculty of Science and Engineering, Southern Cross University, P.O. Box 157, Lismore, NSW 2480, AustraliaSci-Eye, P.O. Box 4202, Lismore, NSW 2480, AustraliaFaculty of Science and Engineering, Southern Cross University, P.O. Box 157, Lismore, NSW 2480, AustraliaAnalysis of animal morphometrics can provide vital information regarding population dynamics, structure, and body condition of cetaceans. Unmanned aerial vehicles (UAVs) have become the primary tool to collect morphometric measurements on whales, whereas on free ranging small dolphins, have not yet been applied. This study assesses the feasibility of obtaining reliable body morphometrics from Australian snubfin (<i>Orcaella heinsohni</i>) and humpback dolphins (<i>Sousa sahulensis</i>) using images collected from UAVs. Specifically, using a dolphin replica of known size, we tested the effect of the altitude of the UAV and the position of the animal within the image frame on the accuracy of length estimates. Using linear mixed models, we further assessed the precision of the total length estimates of humpback and snubfin dolphins. The precision of length estimates on the replica increased by ~2% when images were sampled at 45–60 m compared with 15–30 m. However, the precision of total length estimates on dolphins was significantly influenced only by the degree of arch and edge certainty. Overall, we obtained total length estimates with a precision of ~3% and consistent with published data. This study demonstrates the reliability of using UAV based images to obtain morphometrics of small dolphin species, such as snubfin and humpback dolphins.https://www.mdpi.com/2072-4292/14/1/21aerial imageryinshore dolphinsmorphometricsphotogrammetryUAVs |
| spellingShingle | Anna I. Christie Andrew P. Colefax Daniele Cagnazzi Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins Remote Sensing aerial imagery inshore dolphins morphometrics photogrammetry UAVs |
| title | Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins |
| title_full | Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins |
| title_fullStr | Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins |
| title_full_unstemmed | Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins |
| title_short | Feasibility of Using Small UAVs to Derive Morphometric Measurements of Australian Snubfin (<i>Orcaella heinsohni</i>) and Humpback (<i>Sousa sahulensis</i>) Dolphins |
| title_sort | feasibility of using small uavs to derive morphometric measurements of australian snubfin i orcaella heinsohni i and humpback i sousa sahulensis i dolphins |
| topic | aerial imagery inshore dolphins morphometrics photogrammetry UAVs |
| url | https://www.mdpi.com/2072-4292/14/1/21 |
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