Uses of each technology

How it works: 

Radio is an excellent type of signal to use when tracking animals, in part because radio waves can transmit information rapidly and for long distances in air.  Radio signals can also be made to transmit effectively in fresh water, but not through salt water.

To track an animal with radio, you need to equip it with a device, called a transmitter, that can send you a signal.  In addition, you yourself need to be equipped with a device, called a receiver, that can detect that signal.  Both devices have antennas attached to them to aid them in their tasks. 

To track more than one subject at the same time, you need a way to give each one a unique signal that you can identify.  In conventional biotelemetry, radio signals are made unique by varying either their frequency or their “beeping” rates.  Both strategies have their limitations.  One of Lotek’s great innovations in biotelemetry has been the introduction of the digitally encoded radio tag, which transmits a unique numerical code that differentiates it from all other tags, even those transmitting on the exact same frequency.  This allows a researcher to track hundreds of subjects on any one frequency, which has greatly improved scientists’ abilities to increase the sample sizes of their studies.

Another significant advance has been our miniaturization of radio tags.  We now offer digitally encoded radio tags that are tiny and light enough to be used on fish as small as 10 centimeters (3.9 inches) long.  Quite an improvement over the early days of biotelemetry, when the transmitters themselves were almost that long!

When it’s used:

Radio biotelemetry can be used in water, on land or in the sky.  A huge range of animals can be tracked with this technology: Lotek has radio tags and collars that can be placed on fish, birds, mammals and amphibians of almost any size, from tiny salmon smolts to full-grown elephants.

Lotek radio products

How it works:

Seawater covers more than 70% of the Earth’s surface, and is home to many of its creatures.  But salt water presents unique challenges to those wishing to track marine wildlife.  Radio waves are highly absorbed by salt water, making them a poor choice for sending messages through the ocean. 

Sound waves, on the other hand, are not similarly impeded by seawater.  What’s more, sound can travel more than 4 times faster in water than in air, allowing near real-time listening over long distances with the right tools.  For these reasons, acoustic signals are the preferred communication tool for researchers who wish to track fish and wildlife in marine habitats in real time. 

As with radio, acoustic telemetry requires transmitters to send signals and receivers to hear them.  In between those two, one additional piece of equipment is used in acoustic telemetry.  A hydrophone is a type of underwater microphone that receives acoustic signals, which are then either stored or converted into radio signals for rapid transmission through the air to the receiver on the shore.

Lotek has expanded the boundaries of acoustic telemetry as well.  Our powerful MAP System employs CDMA coding (similar to that found in cell phones) to allow the simultaneous detection of countless unique individuals on a single acoustic frequency.  Equally innovative is the MAP System’s ability to discern its tags reliably even in the acoustically noisy ocean environment.

When it’s used:

Acoustic biotelemetry is generally used to monitor those creatures living or moving in deep water or salt water habitats.  Lotek offers acoustic systems to track a wide variety of marine inhabitants, such as salmon, trout, plaice, cod, crabs, sea turtles, and many others.

Lotek acoustic products

How it works:

Smaller creatures like fish can also be equipped with devices that record and store tracking information for retrieval at a later date.  Known as archival or data storage tags, these instruments are placed in or on fish and act like tiny computers, constantly sensing and recording the environmental conditions that they travel through.  Incredibly, the tags can take new readings as frequently as every 4 seconds if desired.  Despite their small size, Lotek archival tags have batteries and memories with enough capacity to collect data for several years.  They are also constructed to ensure reliable operation at depths of up to 2000 meters and temperatures as low as -5° C.

Archival tags measure water temperature, water pressure and light levels.  From these, researchers can reconstruct an impressively detailed daily history of a fish’s travels.  The pressure reading reveals its precise water depth, and the light measurements contain enough information to allow calculation of the fish’s latitude and longitude, using an elegant process known as light-based geolocation.  The unsurpassed light sensitivity of Lotek archival tags ensures that users can gather the most accurate geolocation estimates possible.

As with some types of GPS work, archival tag research relies on equipment retrieval for its success.  Some tags have labels that offer rewards to whoever catches the fish, and it’s not unusual for these rewards to be claimed from surprisingly faraway locations.  Lotek has also introduced a second retrieval option: archival tags with “pop off” mechanisms.  Like remote-release GPS collars, these tags can be programmed to detach from their subjects at specific times.  Once detached, they float to the surface of the water and emit signals to facilitate recovery.

When it’s used:

Archival tags offer an excellent alternative for monitoring aquatic, avian and terrestrial species when radio or acoustic telemetry is not possible or practical.  Lotek tags have been used on such diverse species as tuna, salmon, cod, plaice, sharks, sablefish, lake trout, turtles, penguins, albatross and platypuses.

Lotek archival products

How it works:

In radio and acoustic systems, signals travel from a transmitter to a nearby receiver.  By contrast, animals equipped with GPS, Argos and Iridium collars do most of their communicating with satellites in outer space.  The collars take advantage of services afforded by two multiple-satellite systems, the “Global Positioning System” (GPS) and the “Advanced Research and Global Observation Satellite” (Argos).  Each system operates in a unique way: GPS satellites transmit positional data to receivers on the ground, while Argos satellites receive positional and other data from transmitters on the ground, and relay that information back to ground stations situated elsewhere.  We manufacture collars that can utilize either system to full advantage.

For example, our GPS collars can take positional snapshots at numerous pre-defined intervals all day long.  The first of their kind, these collars also boast impressive data storage capabilities, keeping a record of the animal’s migratory history until the collar and/or its information is retrieved.  Never before have biologists been able to obtain such a rich and accurate mapping of an animal’s movements, to within an error of less than five meters.

Another exciting innovation has been the addition of remote-release capabilities to our collars.  Biologists can now activate a mechanism that automatically detaches the data-rich collar from the animal.  This eliminates the need to recapture the creature at the end of the study, reducing both the expense to the researcher and potential trauma to the animal.  Once detached, the collar changes its radio beacon signal to help the researcher find it.

When it’s used:

GPS, Argos and Iridium systems are used to track animals such as coyotes, wolves, caribou, sheep, cattle, mountain lions, bears, moose, deer and cougars, as well as sea turtles, marine mammals and birds.  Recently, Lotek has also added GPS locator capabilities to other products, such as our SRX 600 receivers.

Lotek satellite products