Three-dimensional movements within individual dives by ringed seals ( Phoca hispida )

• Published in: Canadian Journal of Zoology
• Main Authors: Simpkins, Michael A, Kelly, Brendan P, Wartzok, Douglas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2001
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Phoca hispida; ringed seal
• Online Access: http://dx.doi.org/10.1139/z01-100; http://www.nrcresearchpress.com/doi/pdf/10.1139/z01-100

We analyzed the three-dimensional movements within individual dives of five freely swimming ringed seals (Phoca hispida). We divided dives into a series of moves, each of which represented continuous movement in one direction, and evaluated several three-dimensional movement variables to distinguish between types of movement within dives. Horizontal directionality proved to be the most useful variable, and we distinguished convoluted and directional movements by fitting a mixture of two normal distributions to the observed horizontal-directionality values. Both convoluted and directional movements occurred within each phase of most dives, suggesting that ringed seals switched between behavioral modes within dive phases. Descent and ascent phases were not simply travel behavior, nor were bottom phases equivalent to patch time, complicating the formulation of optimal diving models for ringed seals. Most ringed seal dives appeared to consist of a series of patch times separated by travel times. Travel behavior accounted for the majority of dive times.