What is Animal Satellite Tracking?


So what is Animal Satellite Tracking?

Welcome to my series on Animal Satellite Tracking. In the coming weeks, I hope to give supply you with a thorough evaluation on what is now becoming the fastest and most well-liked approach used for researching animal ecology, and the greatest tool for science-based conservation.

What are the advantages?

Satellite tracking has the capability to track animals below the ocean’s surface, across nation borders and over vast distances in true time. It has offered conservation groups, scientists and policy makers with techniques to monitor species behaviour and survival, tools that had been in prior decades only available to a pick handful of. This info is critical for understanding the part of animals within the wide systems they operate and how they are likely to respond to variations in these systems due to climate change.

Some positive aspects of satellite tracking contain –

Global coverage – animals can be followed across regional, national and international borders
Newer tags enable a extremely detailed analysis of spatial movements (which were previously not possible to observe)
Researchers do not have to commit a fantastic deal of time in the field (such as in the cold of Antarctica!)
Animals require to be handled only once (traditional tags require recapture)
The tagged animal can be tracked from a pc anyplace in the planet

The technologies is most relevant in the marine atmosphere, where it is almost not possible to straight observe animals over extended periods. This is due to the 3 dimensional nature of movements within the ocean and the reality we can not straight observe animals deep beneath the surface.

A couple of examples of how scientists use tracking data contain:

Observing the movement patterns and speeds of migrating birds, fish or whales
Understanding how deep seals dive when looking for food
Discovering exactly where marine turtles feed among egg laying years
Discovering exactly where a shark species aggregate for mating

This information is important for determining how greatest to manage the animals and the critical habitat they require for survival.  Whether or not determining breeding, feeding or mating grounds, satellite tags have opened our eyes to the exclusive behaviours of animals we have only ever seldom seen.

The Technical Bit

Modern satellite tracking includes an electronic tag or platform transmitter terminal (PTT) that relays data to polar-orbiting satellites operated by the National Ocean and Atmospheric Administration (NOAA) and the European Organisation for the Exploitation of Meterological Satellites (Eumetsat)1. On the satellites, Argos sensors pick up the signal ahead of being re-transmitted to processing centres back on Earth and then to the scientist. This is the standard technique used due to its in-built location determination system and global coverage. The signals sent to the satellites are recorded in two approaches either the Argos satellites decide the location of the transmitting tag or a GPS unit on the tag uploads an accurate set of coordinates to the satellites. How the signal is actually transmitted is exactly where the technologies starts to get a tiny technical for this article but if you are interested you can see it in far more detail on the ARGOS website.

The PTTs themselves are micro-processor controlled archival and transmitting tags, developed to record parameters from each the animal becoming tracked and the environment it inhabits. Info relayed to satellites can include details on latitude and longitude (location on the earth), place accuracy, depth/altitude (including highest and lowest), time wet/dry, light levels and temperature. GPS tags can now also determine speed, altitude and record data at a significantly higher accuracy.  All of this data can then be utilized to piece collectively the day to day life of the animal getting tracked.  Satellite tracking is now recognized as an crucial research tool for understanding the broad and often hidden movement patterns of marine and terrestrial animals.

There are several types of satellite tags obtainable to the researcher, every with their personal advantages and disadvantages.  The key tag categories are:

Transmitting (ARGOS) tags

For the past 30 years, Smart Position or Temperature Transmitting Tags (SPOT5, TAM, CTD, SRDL) have been the most well-known tag kind and are broadly employed by researchers, usually because you don’t have to recapture your animal. Data on the animal’s atmosphere, location and behaviour is sent in actual time and recorded by the ARGOS satellites ahead of the tag’s place is ultimately calculated through the ‘Doppler Effect’ at ground stations. The a lot more satellites the tag transmits info to, the greater the accuracy of the signal. In the marine atmosphere, this technologies is now regarded inferior to a GPS primarily based system due to its inaccuracy of over 1000 metres. This inaccuracy is due to the fact the animal wants to surface for a robust signal to be transmitted. Nonetheless, SPOT5 tags nonetheless remain the least expensive and smallest selection for near genuine time data collection and can be utilized on all species that are at the moment tracked by satellite.

Archival Tags and Pop-up tags

Archival (SPLASH) and Pop-up Archival Tags (PAT or PSAT) have been established more than the last 10 years to be the most effective way of tracking massive scale movements of animals that do not routinely check out the ocean’s surface. This is simply because the tags archive their data for later collection. They shop info like stress (depth), internal (body) and external temperature, ambient light level (time of day and geo-place) and swim or flight speed.

Archival Tags

Archival tags had been very first deployed in the 1990s and have created rapidly more than the previous ten years. The device is generally inserted into the abdominal cavity of a fish (primarily tuna), with the external sensor ‘stalk’ emerging from the body. Information is usually collected at two-four minute intervals, nonetheless researchers can plan the tags to maximize efficiency2. There are a number of computational algorithms that calculate latitude and longitude based on light levels longitude from time of noon/midnight (or nearby moon) and latitude from measurements of day length. The accuracy of this tag kind has been estimated to be much less than 110km2.

Pop-up Tags

PAT tags are related to Archival Tags but are attached to the outdoors of the host animal by a dart and wire or monofilament tether (Figure four). The cable is designed to detach the tag from the animal either:

right after a pre-determined time
when there has been no adjust in depth for a period of 4 days (if the animal has died) or
when the tagged animal swims to a depth that would damage the tag

It is then developed to float to the surface exactly where it transmits its location, time of release and a summary of information to the ARGOS satellite method. PATs, like the a single in figure 4, are made of a carbon fiber housing for streamlining and to safeguard them from the pressures of the oceans depths. The total data set from archival or pop-up archival tags can only be retrieved if the tag is located, either retrieved by fishers or washed up on a beach close to the study web site.  This is why scientists put out rewards for the return of satellite tags, frequently among $ 200 and $ 2000!



Rewards for returning satellite tags can be located at our site or at the Tag a Giant website.



GPS tags

GPS tags have become the ‘go-to’ tag for researchers with a large budget. This tag kind shops its location data before transmitting it to the ARGOS satellites in near genuine time. They are extremely precise, providing an accuracy of significantly less than 70 metres, and transmitting practically 4 occasions as numerous trustworthy locations throughout its time on the animal. This fine-scale accuracy has allowed scientists to analyse behaviours such as daily activity, house variety size, correct everyday migration speeds and the advent of the ‘Daily Diary’.

Are there any disadvantages?

The two most significant disadvantages of satellite tags are the price and the lack of time for which tags function.  Currently oceanic tags, that relay details to satellites, last roughly for a maximum of 1 year due to failures in the battery, salt-water switch failure, antennae breakage, animal mortality and premature detachment. The essential disadvantages are:

The ARGOS technique is expensive, information accuracy is low and upload rates slow. Research usually discard 80 to 90% of fixes.
For GPS tags, the cost of data retrieval can be as considerably as a tag itself!
Tags might have an impact on animal behaviour, compromising data.
Tag loss is a major situation, primarily due to battery failure and unpredictability of the animals being tracked.
Transmitting tags have to have the antennae above the water surface for productive transmission.
SPLASH and PAT tags are notoriously unpredictable in terms of recovery, with earlier studies yielding only 12% tag return.
Tags can only last to a maximum depth of 1500m.
Terrestrial satellite tags are normally as well huge for use on smaller animals such as birds, insects and mammals. There is at the moment no suitable technology for tracking the migration of the biggest group of birds with value to ornithologists, which are the medium to small song birds.
Until not too long ago, tags broadcasting to ARGOS receivers have been a a single-way technique. This means that they could by no means be re-programmed as soon as attached to the target species. Many transmissions are sent since the tag does not know if the signal has been recorded, thus decreasing battery life. This is nevertheless the case with all less expensive models, including SPOT5 tags.


For a full list of references please see this blog post on our website.