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What Is Telemetry?

Telemetry allows scientists to collect data remotely via wire, radio, satellite, or data recorder. In biology, researchers use telemetry to collect data that would otherwise be unobtainable: telemetry devices can help us understand animal behavior, function, and movement throughout the environment by recording information such as temperature, pressure, depth, and location. Telemetry is especially helpful in the marine environment, where animals spend most (if not all) of their life in the water.

Types of Tags

A variety of telemetry tags that can be attached or implanted into host animals for data collection. Tag choice depends upon a number of factors, such as animal life history, habitat type, type of data needed, length of data collection, and the type of resources available to the researchers for data collection. Depending on the need, researchers may choose tags that store information for later retrieval or transmission, or they may choose tags that transmit data continuously (or whenever in range of a receiver).

Tags that store information for later use are known as archival tags. For data collection to occur, researchers must collect the tag – or the animal to which it’s still attached. In either instance, data collection can be problematic and time consuming. Tags of this nature are often only used in very specific circumstances when the barriers to collection can be more easily overcome.   

Transmission tags do not require collection or recapture. Instead, these tags transmit data to a receiver whenever the animal is in range, or in the case of marine animals, whenever the animal breaks the surface of the water. Transmitter tags can be used to track an animal’s location via satellite (GPS), radio (VHF radio tags), and acoustic pulses (acoustic tags). Passive integrated transponder (PIT) tags can be used to identify individual animals.

Some tags can combine features of archival and transmitting tags. Life History Transmitters (LHX), a special type of archival tag, are implanted into a host animal’s abdominal cavity. The tags store life history information throughout the animal’s life. When released (generally upon the host’s death), the tag senses air or light, and begins to transmit the stored information. LHX tags are currently being used to study Steller sea lion life history.

Another combination tag, the pop-up tag, records data and then pops off after a preset threshold (such as depth or time) has been reached. . Once free of the animal, the tags can transmit their information or be collected for data download. Pop-up tags are particularly useful for studying animals that rarely come to the ocean’s surface (like sharks!).