The Argos Wildlife Monitoring System

April 13, 2020

The Technology Behind Animal Telemetry

Woods Hole Group’s Thomas Gray

If the success of the Discovery Channel’s Shark Week is any indication, people have an intense fascination with this apex predator. The globe-trotting popular television event, which has been on the air since 1988, would not have been possible without the telemetry systems that have allowed filmmakers and biologists to locate and document the behaviors of previously tagged animals.

One of these systems, Argos, is among the leading technologies employed to tracks thousands of animals around the world. In the especially challenging marine environment where conditions can rapidly change, oceanic currents are ever shifting, and salinity is high, “Argos transmitters can record for many months or even years the depth, temperature, and other sensor information of the water through which (marine fauna) move and transmit this information to specialists on land who can then either directly track or reconstruct an animal’s trajectory.” The Argos satellite system is the only system used in the world to track sharks at the surface. The only alternative is to track them via acoustic tags which require a network of listening stations mounted on the seafloor.

OCEARCH, a research organization which helps scientists collect data on different animal species throughout the world’s oceans and then shares this information in a highly interactive online database, uses Argos’ satellite system exclusively for tracking all of the sharks via satellite in their system.,, and the Animal Telemetry Network (ATN) – which is funded through the Office of Naval Research, the Bureau of Ocean Energy Management, and NOAA Integrated Ocean Observing System – also use Argos. ATN also pays for the Argos service of many users, currently covering costs for 1,129 tags.

Since 2016, Thomas Gray has worked with the Woods Hole Group – a subsidiary of the French company CLS which have been responsible for commercializing the Argos system since the mid 1980’s – where he manages the communication, outreach, and marketing of Argos in North America for wildlife users. Late last month, MTS spoke with Thomas Gray about the history of Argos, how the telemetry system functions, and how their network will be expanding its reach in the near future.

MTS: Tell us a bit about the history of Argos.

Thomas Gray: Argos has been around since the 1970’s, tracking thousands and thousands of animals around the world, but we also track oceanographic equipment, fishing vessels, and other assets. We receive and process two million messages per day at our headquarters in Toulouse, France. In the United States, we have offices in Bourne, MA – our headquarters; Lanham, MD; Houston, TX; and satellite offices in Delaware, Florida, and myself out in California.

MTS: What types of animals does Argos track and in what environments?

TG: We track about 8,000 animals at any given time around the world, and we manage about 60% of those animals here in North America. Of these animals about 1,800 are marine, including sharks, tuna, otters, seals, whales, etc. The remaining majority of those tracked here in North America are avian species. Something interesting to note, Argos has mapped the migration of the Arctic Tern, the longest mapped migration of any animal on Earth.

MTS: Can anyone utilize Argos or is meant strictly for monitoring animal populations and movements?

TG: To use the Argos satellite system, the application must be of environmental nature. For example, (a commercial fishing vessel) cannot track a tuna in order to find the school of tuna. Each user of the system must have their application approved by the associated space agencies (NOAA, NASA, etc.) before they can use the tags on the system. We have developed and released the first open-source kit which means that anyone can develop an Argos tag with ease. This will level the playing field because it allows universities, NGOs, and similar groups to develop their own tags in-house. These kits are quite inexpensive, too, with each unit priced between $350-500.

MTS: Once an animal is tagged with an Argos beacon, how often is the animal’s position able to be tracked?

TG: We currently have seven polar-orbiting satellites today which provides approximately fifteen minutes of satellite coverage every 1 to 1.5hrs. The satellites collect position and sensor data from tagged animals as they pass over them. In December 2019, the French Space Agency, CNES, launched the first Argos nanosatellite, ANGELS. In 2022 we intend to launch an additional 20+ nanosatellites to bring the entire number upwards of 25-30 satellites. When fully functional, this constellation of nanosatellites will allow data about the position of tagged wildlife to be transmitted every 10-15 minutes (instead of hours) between satellite passes. In addition, the new constellation will add two-way communication and a dedicated part of the frequency bandwidth for wildlife tracking only.

MTS: With such an ambitious expansion plan on the horizon, how is Argos able to be financially solvent?

TG: Argos is developed on a cost-recovery structure which means that the revenue that we get from Argos users goes directly towards the operation of the system itself. The operational cost is shared among all users, and due to a variety of changes and general increased use, the system cost, for the end users, was reduced by nearly 50% at the beginning of 2018. That price will continue to be driven down as more tags are deployed and new applications come on line.

MTS: Any random/fun facts about Argos that you can share with us?

TG: Sure. The largest animal tracked by Argos is the African elephant; the smallest is the mangrove cuckoo; and the giant jellyfish is probably the most unlikely tagged animal. The lowest recorded temperature by Argos was in Antarctica, -84.6C (brrrrrrrrrrrrr).

More information the Argos wildlife monitoring system can be found here.

  • Lake Trout tagged with an Argos tag. Photo by Daniel Traynor, Michigan Department of Natural Resources.

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