Tags Tell Travelling Whale Tales
Technology has allowed humans to learn an incredible amount of information about how we travel in our environment. A new study even suggests that every time we carry a cell phone, we create digital “fingerprints” of our positions on Earth. These movement patterns are so unique, that you could be identified with 95% accuracy based on the locations you visited, even if your cell phone transmits your location as infrequently as once per hour. Of course, you might be wondering what that has to do with cetaceans (dolphins, whales, and porpoises). After all, it’s not like we can give them cell phones to track their mysterious underwater movements. However, by using some of the same principles, researchers can now use satellite tags to investigate where whales go when out of sight.
Early tagging technology
The first tags used to track cetaceans were deployed in 1932 by the Discovery Committee, which collected data on whaling catches. A tag, labeled with a serial number and return address, was embedded into the blubber of a swimming whale. Whalers were then rewarded for reporting information about their catch to the Committee after a tag was found on a caught whale. Since then the sharp decline in whaling and the advancement of technology has allowed tagging to become a much safer way to track cetaceans.
Today, tags send signals to satellites
Unlike the Discovery tags, modern tags are less invasive and more informative. One of the most important components of contemporary tag technology is the ability to use a network of satellites that collect, process, and distribute tag data. The Argos satellite system is an example of such a network – it was established in 1978 to collect geographic location data from transmitters on Earth. Since the 1980s, satellite tags have been routinely used to track marine mammals and sea turtles.
Argos satellites, which orbit 850 kilometres above Earth, receive signals from a transmitter embedded in a deployed tag. After these signals are received by an Argos satellite, they are relayed in real time to receiving stations back on the ground (there are 40 around the globe). The data are then sent to a processing centre in Toulouse, France or Washington, D.C., U.S.A. The processing centres perform calculations on the data and then distribute them to users. Amazingly, the entire process can take as little as 20 minutes.
What’s the point?
The information collected from tags plays a crucial role in marine conservation and fisheries management. Tag technology allows researchers to gather information not just on the location of an animal, but also dates, times, water temperatures, ambient noise levels, light levels, body temperature, depth, and even noise made by the tagged animal.
Arguably one of the most useful applications of satellite tags is their ability to track migratory whales over long periods of time. One study deployed Argos satellite tags on 159 blue whales (Balaenoptera musculus) from 1993 to 2007 with the purpose of finding out more about the species’ poorly understood annual migration patterns. The project was able to identify critical habitats for blue whales, an incredibly important conservation tool for protecting the cetacean designated as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).
Sightings can help too
As far as tagging technology has come, it is often extremely expensive and logistically complex. That’s why many researchers opt to also monitor cetacean movement using less complicated means, such as observation. You can directly participate in the research and tracking of cetaceans by reporting any sighting to the B.C. Cetacean Sightings Network by calling 1-866-I-SAW-ONE or online here. To learn more about satellite tracking, check out how the Vancouver Aquarium studied the movements of Levi the rehabilitated harbor porpoise on the AquaBlog.