Mk10-PAT Pop-up Archival Transmitting Tag

April 2013 - The venerable Wildlife Computers Mk10-PAT tag, which has been in service on a variety of species for many years, has reached the end of a very successful life.

Three and a half years ago, we introduced the MiniPAT in response to requests from the research community for a smaller pop-up tag. The MiniPAT, which is 30% smaller than the Mk10-PAT, has proven to be as reliable as its predecessor.

The MiniPAT’s smaller size allows smaller species to be studied and improves retention. The MiniPAT also offers additional features, such as

• two light sensors for cleaner light measurement to improve geolocation
• a dynamically determined sampling interval of Time-Series messages for premature releases, to give you better insight to the potential cause of the premature release
• a UHF pinger to assist in tag recovery
• additional message types such as the Mixed-Layer Analysis messages

In addition, the MiniPAT maintains compatibility with the data generated by the Mk10-PAT, and incorporates a more efficient transmitter that delivers even more data to you.

As we retire the Mk10-PAT, due in part to component obsolescence, we know that the MiniPAT is an excellent and reliable successor which will support your new and on-going research projects. Please contact us if you have questions about the transition of the Mk10-PAT to the MiniPAT.

If you require a towed tag with pop-up capabilities, or a tag for any other specialized application, we invite you to contact us about your needs.

For those who may need historical information on this tag, we will leave the following Mk10-PAT product information on the site for the the time being.

Our Pop-up Archival Transmitting (Mk10-PAT) tag is a sophisticated combination of archival and Argos satellite technology. It is designed to track the large-scale movements and behavior of fish and other animals which do not spend enough time at the surface to allow the use of real-time Argos satellite tags.

The Mk10-PAT adds the Wildlife Computers Cricket Argos transmitter to the standard Mk10 archival tag. A bouyant body and a corrodible pin allows the release of the Mk10-PAT from the fish so data can be transmitted.

Transmitted data You can program the PAT to selectively transmit time-at-depth and time-at-temperature histograms, depth-temperature profiles, and/or light-level curves. You also set the histogram duration (1 to 24 hours) and bin ranges. This provides the flexibility to customize data collection to best achieve different experimental objectives.

Fisheries-independent tracking, archival data Because the PAT can yield data without the animal being recaptured, it offers a fisheries-independent means of tracking a target species. In addition, a full archival record is maintained in non-volatile memory. Thus, should the PAT be recovered, you have the same detailed data that are collected by a conventional archival tag. A surprising number of PATs have been recovered by beachcombers and fisheries, giving the researcher a complete record of the animal’s behavior.

PATs are best-suited for large pelagic animals. PATs have been deployed on a variety of species, including large tuna, marlin, and sharks, as well as swordfish and sea turtles. The PAT tag is attached to the animal via a tether. Generally, the researcher determines the best tether design and attachment method.

How the PAT works The PAT archives depth, temperature, and light-level data while being towed by the animal. At a user-specified date and time, the PAT actively corrodes the pin to which the tether is attached, thus releasing the PAT from the animal. The PAT then floats to the surface and transmits summarized information via the Argos system. Argos also uses the transmitted messages to provide the position of the tag at the time of release. The transmitted data are sent to the researcher by Service Argos. The data can be analyzed further by the researcher using Wildlife Computers PC-based software. The results provide the migration path taken by the study animal, depth and temperature preferences of the study animal, as well as oceanographic data in the form of depth-temperature profiles. Data from deployed PATs have revealed interesting and often unanticipated information on the depth and temperature preferences of these animals.

All aspects of the PAT’s data collection and transmission are user-programmable. This simplifies the logistics of your experiment design; you do not need to pre-specify these parameters before ordering the tag.

The PAT recognizes attachment failures and animal mortality Data from the PAT also offer insights into attachment failure and animal mortality. The PAT’s on-board software includes a “Premature Release” feature. This feature monitors how long the PAT remains at a “constant depth.” Constant depth readings imply the PAT is floating at the surface or sitting on the sea floor. Among the parameters set by the user are a threshold duration (24-192 hours) and depth variance (in meters). The threshold duration is the longest time a healthy animal should remain at a constant depth, and the depth variance is the number of meters the depth may vary but still be considered “constant” (necessary to account for tidal effects). The PAT recognizes a “premature release” event when it has been at a “constant” depth for longer than the threshold duration.

When the PAT recognizes a premature release, it initiates its release process and begins transmitting, rather than waiting for its release date. This gives you immediate notification that something has gone wrong, the location of the event (via the Argos location of the pop-up site), and minimizes the chances that something will damage the tag between the premature release event and the programmed release date.

Insurance against being crushed at depth Wildlife Computers has developed a mechanical release, called the RD1800, that prevents the PAT from being dragged to depths that would crush it. This releases the PAT so that it floats to the surface. The Premature Release feature will recognize a “constant depth” situation and initiates transmission. Thus the PAT will transmit even in the event of attachment failures, animal mortality or unexpected animal behavior.

Transmitter The Mk10-PAT is our first PAT tag to incorporate the Cricket, a specialized Argos transmitter developed by Wildlife Computers. The Cricket offers the additional advantage of transmitting effectively even when dry (on the beach or in a boat). It generates 0.5W of radiated power output. The high-efficiency and frequency-stability of this transmitter maximize the quantity and quality of messages.

Battery and deployment length A lithium battery supplies enough power for the PAT to sample data for at least one year and make 10,000 32-byte transmissions over the course of about 7 days. The researcher can tailor the scale of the transmitted data so that it is appropriate for the deployment length (e.g., fine-scale for short-term deployments). The deployment length currently is limited by the challenge of keeping a tag on the study animal.

Controller features The operating code of the PAT can be upgraded. This means you can always have the most up-to-date version of on-board software, regardless of when the tag was purchased. The on-board clock is temperature-compensated to keep time accurately between 0°C and 40°C. This ensures precisely-timed data readings and an accurate release date.

Tag activation The PAT tag can be turned on and off with a magnet. The LED flash sequence indicates whether the tag is in standby mode or deployed.

Memory The PAT has 64 MBytes of non-volatile flash memory to store archival and summarized data. This is enough memory to store all summarized and sampled data for all deployments in which the sensors are sampled no faster than every 5 seconds. These data are retained even if the battery is exhausted. This means your archival data can be recovered if your PAT is found washed up on a beach after it pops off, and many are!

Sensors 12-bit analog-to-digital converters provide high-accuracy depth and temperature readings. A 10-bit analog-to-digital converter is used for light-level and battery voltage readings, as well as other housekeeping chores. Depth and temperature sensors are calibrated to provide an accuracy of 1% of the measurement. Depth and light level are temperature-compensated to provide consistent readings through temperature variations.

• Depth is measured from 0 to 1000m with a resolution of 0.5m.
• Temperature is measured from -40°C to +60°C with a resolution of 0.05°C.
• Light level is measured as irradiance at a wavelength of 550nm. The sensor measures from 5 x 10^-12 W.cm^-2 to 5 x 10^-2 W.cm^-2 in logarithmic units. Dawn and dusk events can be discriminated at depths up to 300m in clear water conditions.

User-defined parameters All parameters are user-programmable using a PC. You are able to set the release date, data collection, and all other parameters that control how and when the PAT stores and transmits its data.

Location accuracy Service Argos provides the pop-off location with an accuracy as good as ±350m. Daily longitude and latitude can be calculated from transmitted light-level curves by the researcher using WC-GPE, a PC-based software developed by Wildlife Computers. Longitude accuracy is approximately±1 degree. Latitude accuracy depends upon both the latitude and time of the year. Best accuracies (±1 degree) are achieved at high latitudes near the solstices, and worst occur near the equator near the equinoxes (±10 degrees, where and when latitude can be calculated).

Size, weight and pressure resistance Electronic components are fully cast in a tube measuring 21mm in diameter. The added float measures approximately 40mm in diameter at its widest point. Overall length of the tag, not including the antenna, is 175mm. Total weight is 75g in air. The cast tube and float are tested and confirmed to withstand 2000m of pressure.