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

We analyzed the three-dimensional movements within individual dives of five freely swimming ringed seals (Phoca hispida). We divided dives into a seri es 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 t o be the most useful variable, and we distinguished convoluted and directio nal movements by fitting a mixture of two normal distributions to the obser ved horizontal-directionality values. Both convoluted and directional movem ents occurred within each phase of most dives, suggesting that ringed seals switched between behavioral modes within dive phases. Descent and ascent p hases were not simply travel behavior, nor were bottom phases equivalent to patch time, complicating the formulation of optimal diving models for ring ed seals. Most ringed seal dives appeared to consist of a series of patch t imes separated by travel times. Travel behavior accounted for the majority of dive times.