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Pop-up satellite archival tags (PSATs) are used to track movements of (usually large, migratory) marine animals. A PSAT (also commonly referred to as a PAT tag) is an archival tag (or data logger) that is equipped with a means to transmit the collected data via satellite. Though the data are physically stored on the tag, its major advantage is that it does not have to be physically retrieved like an archival tag for the data to be available making it a viable, fishery independent tool for animal behavior studies. They have been used to track movements of ocean sunfish, marlin, blue sharks, bluefin tuna, swordfish and sea turtles. Location, depth, temperature, and body movement data are used to answer questions about migratory patterns, seasonal feeding movements, daily habits, and survival after catch and release, for examples.〔Some examples include: Block, B, Dewar, H, Farwell, C, Prince, ED. A new satellite technology for tracking the movements of Atlantic bluefin tuna. Proc. Natl. Acad. Sci. USA Vol. 95, pp. 9384–9389, August 1998; Hoolihan, John P. Horizontal and vertical movements of sailfish (Istiophorus platypterus) in the Persian Gulf, determined by ultrasonic and pop-up satellite tagging. Marine Biology (2005) 146: 1015–1029 DOI 10.1007/s00227-004-1488-2;Stokesbury, MJW, Harvey-Clark, C, Gallant, J, Block, BA, Myres, RA. Movement and environmental preferences of Greenland sharks (Somniosus microcephalus) electronically tagged in the St. Lawrence Estuary, Canada. Marine Biology (2005) 148: 159–165 DOI 10.1007/s00227-005-0061-y〕 A satellite tag is generally constructed of several components: a data-logging section, a release section, a float, and an antenna. The release sections include an energetically popped off release section or a corrosive pin that is actively corroded on a preset date or after a specified period of time. Some disadvantages of using satellite tags are their depth limitations (2000m), their costs ($499–4000+), and their vulnerability to loss by environmental issues (biofouling) or ingestion by a predator. For the satellite tags that function by measuring ambient light, they have a functional depth limitation of light penetration which can be as shallow as a few meters to upwards of 1000 meters. Additionally these tags cost between $4000+ per unit which is the main reason many studies employ a dozen or fewer of these tags. Geolocation estimates based on light are generally less reliable, not available in dark or turbid waters, and of no use during times of the equinoxes. For the satellite tags that function by measuring ambient light and the Earth's magnetic field, they have a functional depth limitation equivalent of the maximum depth limitation, generally 2000m. These tags are generally used in much higher quantities due to their advanced geolocation capabilities and lower cost ($499–2500). These tags offer sensory functions not available in light only tags such as body movement parameters, higher precision depth sensing, and re-usable release sections. However, there is only one manufacture of these tags, Desert Star Systems. ==General information== Pop-up satellite tags range in length from about and weigh 36-108 grams in air. A tag must be small compared to the size of the animal, anywhere from 3-5% of the total fish weight, so that it does not interfere with normal behavior. Smaller versions of about half that length and weight have been recently introduced and are more suitable for use on smaller species or younger animals. Furthermore, the SeaTag-GEO/PSAT is the lightest PSAT manufactured at under 30 grams including its float, release section, and antenna. These tags record such information as temperature, magnetics, acceleration, light level, and pressure at set intervals of a few seconds to several hours.〔Block, Ba, Dewar, H, Farwell, C, Prince, ED. A new satellite technology for tracking the movements of Atlantic bluefin tuna. Proc. Natl. Acad. Sci. USA Vol. 95, pp. 9384–9389, August 1998; Nielson, A, Bigelow, KA, Musyl, MK, Sibert, JR. Improving light-based geolocation by including sea surface temperature. Fish. Oceanogr. 15:4, 314–325, 2006.〕 Data are often collected for several weeks or months but with new advances in memory technology microSD cards tags can store data for centuries. PSATs record data in non-volatile memory so that data are retained even if battery or solar power runs out. When the PSAT releases from the animal on which it was attached, it floats to the surface, and begins to transmit data to of the Argos satellites at a frequency of 401.65 MHz. Therefore, the tag does not have to be physically recovered for the data to be obtained. Depending on the number and coverage of the satellites, it can take 7 to 10 days or longer for the data to be completely transmitted. Major disadvantages of the PSAT are that it is subject to loss by malfunction of any key component, environmental effects such as biofouling, ingestion by a predator, its depth limitation and cost. Most PSATS have internal software designed to detect damaging or sub-optimal conditions that will trigger an early release and transmission of data. For example, PSATs can withstand pressures to depths of depending on the model. If data indicate no change in pressure (depth) for a period of time, this could indicate an early release due to malfunction or death of the animal to which it was attached. Such internal checks can alert researchers to unexpected or undesirable events. Ingestion by a predator is more difficult to detect; loss of ambient light might trigger release, but the device may not be free to float to the surface as designed.〔Kerstetter, DW, Polovina, JJ, Graves JE. Evidence of shark predation and scavenging on fishes equipped with pop-up satellite archival tags. Fish. Bull. 102:750–756 (2004).〕 Previously the costs of these tags $4000 was the main impediment to researchers using more than a dozen units during a project. With small sample sizes, the loss of a single tag and average reporting rate of 80% can significantly affect the results. Also, there is greater risk that the animals tagged could display unusual behavior or only one of several types of behavior. Thus an observer could come to an incorrect or incomplete generalization about the entire species. However, with recent technologies and manufacturing capabilities, tag equipment costs have significantly dropped to $499 per tag. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pop-up satellite archival tag」の詳細全文を読む スポンサード リンク
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