Role of Size We developed a new, innovative technique for measuring the sizes of whales underwater. The technique uses a digital video camera operated by a snorkeler to obtain lateral or dorsal full-body views of a whale, and a hand-held sonar device to measure the distance from camera to whale. The camera lens is set at a fixed angle of view. The resulting images and distance data are processed off-line through Photo Shop to obtain actual sizes based on the ration of the whale’s image size to the known field of view of the camera lens at the measured distance. Preliminary results showed that females with calf (hence, sexually mature females) were on average larger than accompanying escorts. Further, the sizes obtained for females with calf and escorts (males) compared well with measurements made by biologists of sexually mature females and males killed by whalers (Spitz, Herman & Pack, 2000).Spitz, S. S., Herman, L. M. & Pack, A. A. (2000). Measuring sizes of humpback whales (Megaptera novaeangliae) through underwater videogrammetry. Marine Mammal Science 16, 664-676. Back to Top Dolphin Programs | Whale Programs | Education Programs | Our Research | Resource Guide Copyright © 2002, The Dolphin Institute |
