Photo of the beach in Port Aransas, Texas

Polar Projects

These projects are all on the theme of biologging: attaching instruments to animals to learn about their behavior and their environment. A good place to start is: http://www.nsf.gov/news/special_reports/animals/seal.jsp

Behavior of Midwater Fishes Under the Antarctic Ice: Observations by a Predator: We used video sequences with synchronized positional data recorded by Weddell seals to describe the vertical distribution, diel movements, trends in abundance, and swimming behavior of two ecologically important fish species in McMurdo Sound, Antarctica. Pleuragramma antarcticum occurred in loose aggregations (individuals 2 - 4 m apart) and migrated daily between mean depths of 252 m at night and 346 m by day (vertical transit of 94 m). Their depth during November was correlated with surface light intensity even in the absence of a daily sunset. Interannual variations in local abundance indicated that the Pleuragramma population did not remain stationary. Large Dissostichus frequently occurred at shallow depths (12 - 180 m) and showed a significant change in depth with time of day. Dissostichus encounters followed a diel cycle having a mean depth of 93 m, a nighttime minimum of 17 m, and a daytime maximum of 168. Their depth was not correlated with surface light intensity. Dissostichus were present even when Pleuragramma, their principal prey, were scarce. When chased by a seal, one Dissostichus sustained a speed of 3.4 m s^-1 for a period of 24 s.

Weddell Seal Foraging: Behavioral and Energetic Strategies for Hunting Beneath the Antarctic Fast-Ice: The primary objective of this study is to investigate the behavioral and energetic adaptations that enable Weddell seals (Leptonychotes weddellii) to forage in the Antarctic fast- ice environment. To achieve this goal, we will examine the underwater behavior, locomotor performance (swimming velocity, stroke frequency, and three-dimensional movements) and energy metabolism of Weddell seals during foraging dives. We will test hypotheses on general foraging strategies, searching behavior, searching mechanics, modes of swimming, metabolic costs of foraging, and foraging efficiency for different environmental conditions and prey type.

Strategies for Cost-Efficient Diving in Marine Mammals: Locomotor activity by diving marine mammals is accomplished while breath-holding and often exceeds predicted aerobic capacities. Video sequences of freely diving seals and whales wearing submersible cameras reveal a behavioral strategy that improves energetic efficiency in these animals. Prolonged gliding (greater than 78% descent duration) occurred during dives exceeding 80 meters in depth. Gliding was attributed to buoyancy changes with lung compression at depth. By modifying locomotor patterns to take advantage of these physical changes, Weddell seals realized a 9.2 to 59.6% reduction in diving energetic costs. This energy-conserving strategy allows marine mammals to increase aerobic dive duration and achieve remarkable depths despite limited oxygen availability when submerged.

Contact: Lee A. Fuiman
Modified: Friday September 29, 2006