A method for reconstructing three-dimensional dive profiles of marine mammals using geomagnetic intensity data: results from two lactating Weddell seals

• Published in: Polar biology Vol. 26; no. 5; pp. 311 - 317
• Main Authors: MITANI, Yoko, SATO, Katsufumi, ITO, Shinichiro, CAMERON, Michael F, SINIFF, Donald B, NAITO, Yasuhiko
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-05-2003; Berlin Springer Nature B.V
• Subjects: Animal behavior; Animal, plant and microbial ecology; Aquatic mammals; Biological and medical sciences; Breastfeeding & lactation; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Leptonychotes weddellii; Marine; Marine biology; Marine mammals; Methods and techniques (sampling, tagging, trapping, modelling...); Posture; Seals; Southern Ocean; PSE, Antarctica, Victoria Land, Arrival Heights, McMurdo Sound; Geomagnetism; Carnivora; Leptonychotes weddelli; Pinnipedia; Velocity; Profile; Marine environment; Measuring instrument; Vertebrata; Mammalia; Investigation method; Body movement; Diving; Tridimensional image
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-003-0487-y

The under-ice behavior of two free-ranging female Weddell seals (Leptonychotes weddellii) was studied using geomagnetic, acceleration and velocity sensors at Big Razorback Island in McMurdo Sound, Antarctica. The seals' body angle and posture were calculated from the acceleration data and the heading from the geomagnetic intensity data. Together with swim speed, the seals' three-dimensional underwater dive path, heading and even posture were reconstructed for each dive. Each instrument was deployed for 2 days, during which time these females made multiple, deep (50 m) dives, with average maximum depths of 236 plus or minus 27 m (n=4) and 244 plus or minus 121 m (n=40). Each seal appeared to choose a particular heading on which to descend. These headings were significantly different between seals and bouts (Watson'sU super(2) test,P<0.05). These new instruments and methodologies are shown to provide valuable information on the fine-scale and complex movements of diving animals.