Marine telemetry uses devices attached to animals to gather data. These telemetry devices, called tags, are attached to a wide range of marine species, from tiny salmon smolts to giant 150-ton whales. Tags are attached to the outside of an animal with clips, straps, or glue, and are sometimes surgically inserted in an animal's body. Signals from the tags are received by research vessels, buoys, and satellites.
Telemetry tags don’t just report the animal’s movements; they can also also record information about the animal (temperature, heart rate, oxygen levels), its behavior (vocalizations, breathing, tail beats), and its environment (sound, temperature, salinity, light).
These observations significantly improve our understanding of animals’ locations and how they respond to climate change and human-made disturbances. Telemetry data also improves population estimates and aids implementation of the Endangered Species Act and other conservation laws and policies. Marine telemetry can also provide data at relatively low cost and in areas that are difficult to study, such as the Arctic.
As the Earth’s climate continues to change, data collected by telemetry tags can tell scientists the effect of warmer ocean water on animal behavior, their migration patterns, and the availability of their food sources. For example, during an unusual influx of warm water along the West Coast in 2005, telemetry showed that sea lions traveled farther than normal from the shore. Data from the tags showed the sea lions made these trips to find the fish species in the region that make up much of their diet. The data from telemetry tags helped scientists understand more not only about the sea lions, but also about their preferred prey.