Biologging -- the use of miniaturized electronic tags to track animals in the wild -- has revealed previously unknown and suprising behaviors, movements, physiology and environmental preferences of a wide variety of ocean animals. For instance, biologgers have recorded 5,000 foot (1,550 m) dives by Atlantic bluefin tuna, followed journeys of elephant seals halfway across the Pacific from their breeding beaches, and observed annual 40,000 mile migrations of sooty shearwaters -- the longest recorded for any animal. Biologging science is showing researchers how animals work in the furthest reaches of the ocean environs and is advancing both basic and applied research.The technique is being used in new and exciting ways to determine marine and bird behavior. Three-dimensional tags can be used to identify mating events in free-living nurse sharks as well as study the beak movements of loggerhead turtles. Other techniques allow the measurement of vital signs such as body temperature, oxygen utilization and heart rate.
Another use is referred to as "Animals as ocean sensors." "Elephant seals, for example, can sample the water column up to 60 times per day, reaching depths of 1000 m or more under their own power, across broad expanses of the ocean that are difficult to reach by ship or other conventional means."
The whole report is available at Science Daily.