PIT Tags
PIT (Passive Integrative Transponder) Tags are wildlife tracking tags that do not require power. Instead, they have an internal microchip that is activated when it passes close to a special antenna. The antenna is connected to a computer that records the identity of the tag and the time that it passed by the antenna, similar technology to transponders on toll roads (Prentice 1990). These tags are an important tool for wildlife researchers because they allow scientists to track individual organisms by providing a reliable lifetime 'barcode' for each individual animal (Smyth 2013). The use of internal PIT tags began in the mid-1980s with scientists measuring fish movement, but has since been expanded to include the study of mammal, amphibians, reptile, bird, and invertebrate movement (Gibbons & Andrews 2004). PIT tags are commonly used as an alternative to traditional mark-recapture sampling methods to measure growth rates, survivorship, food webs, and movement patterns because marked animals do not need to be physically recaptured; they just need to pass by an automated reading system antenna, such as the one illustrated above (Smyth 2013). For freshwater fisheries science, this technology can be especially useful for studying fish movement in small creeks, where an antenna array can be placed throughout the entire river and records all fish movement up or downstream of that antenna (Prentice et al. 1990).
While PIT tag technology is beneficial in that it only requires catching organisms to deploy the initial tag and maintenance on antenna arrays, the technology is not perfect. PIT tags are inserted into the body cavity or muscle of fishes (Ficke e t al. 2010). PIT tags are available in multiple sizes, with bigger tags more easily picked up by antenna, but the use of bigger tags in some species or size classes of fish may lead to reduced swimming performance and survival (Ficke et al. 2010). Tag retention in fishes is generally ~ 95-98%, suggesting that a small proportion of tagged animals lose their tags and will never be redetected by an antenna. Further, the interpretation of PIT tag detections can be confounded by the presence of ghost tags, or tags that are released into the stream when a fish dies and its body decomposes; these tags wash downstream through antenna arrays, and can lead to false mark-recapture data (Bond et al. 2018).
In small creeks, PIT tags can be read by antenna arrays, as illustrated here. These systems are composed of a transceiver, two antennas spanning the width of the water column, a method of data collection (such as a laptop), and a power system. Passive tags do not contain an internal battery, but obtain power inductively from the electromagnetic field generated by the antenna. The two antenna are set up around 2-3 meters apart, one upstream and one downstream, so that not only will the antenna pick up which fish is swimming in the area, but also will record directionality that the individual is swimming based on which antenna is pinged first.
Sources:
Bond, R.M., Nicol, C. L., Kiernan, J. D., & Spence, B. C. (2018) Occurrence, fate, and confounding influence of ghost PIT tags in an intensively monitored watershed. Canadian Journal of Fisheries and Aquatic Sciences.
Ficke A. D., Myrick, C. A., & Kondratieff M.C. (2010) The effects of PIT tagging on the swimming performance and survival of three nonsalmonid freshwater fishes. Ecological Engineering 48: 86-91. doi:10.1016/j.ecoleng.2011.07.011
Prentice , E. F., Flagg T. A., McCutcheon C. S., & Brastow D. F. (1990) PIT-Tag monitoring systems for hydroelectric dams and fish hatcheries. American Fisheries Society Symposium 7: 323-334.
Smyth, B. & Nebel, S. (2013) Passive Integrated Transponder (PIT) Tags in the Study of Animal Movement. Nature Education Knowledge 4(3):3
Gibbons, W.J. & Andrews, K.M., (2004) PIT Tagging: Simple Technology at Its Best, BioScience 54 (5): 447–454, https://doi.org/10.1641/0006-3568(2004)054[0447:PTSTAI]2.0.CO;2
PIT (Passive Integrative Transponder) Tags are wildlife tracking tags that do not require power. Instead, they have an internal microchip that is activated when it passes close to a special antenna. The antenna is connected to a computer that records the identity of the tag and the time that it passed by the antenna, similar technology to transponders on toll roads (Prentice 1990). These tags are an important tool for wildlife researchers because they allow scientists to track individual organisms by providing a reliable lifetime 'barcode' for each individual animal (Smyth 2013). The use of internal PIT tags began in the mid-1980s with scientists measuring fish movement, but has since been expanded to include the study of mammal, amphibians, reptile, bird, and invertebrate movement (Gibbons & Andrews 2004). PIT tags are commonly used as an alternative to traditional mark-recapture sampling methods to measure growth rates, survivorship, food webs, and movement patterns because marked animals do not need to be physically recaptured; they just need to pass by an automated reading system antenna, such as the one illustrated above (Smyth 2013). For freshwater fisheries science, this technology can be especially useful for studying fish movement in small creeks, where an antenna array can be placed throughout the entire river and records all fish movement up or downstream of that antenna (Prentice et al. 1990).
While PIT tag technology is beneficial in that it only requires catching organisms to deploy the initial tag and maintenance on antenna arrays, the technology is not perfect. PIT tags are inserted into the body cavity or muscle of fishes (Ficke e t al. 2010). PIT tags are available in multiple sizes, with bigger tags more easily picked up by antenna, but the use of bigger tags in some species or size classes of fish may lead to reduced swimming performance and survival (Ficke et al. 2010). Tag retention in fishes is generally ~ 95-98%, suggesting that a small proportion of tagged animals lose their tags and will never be redetected by an antenna. Further, the interpretation of PIT tag detections can be confounded by the presence of ghost tags, or tags that are released into the stream when a fish dies and its body decomposes; these tags wash downstream through antenna arrays, and can lead to false mark-recapture data (Bond et al. 2018).
In small creeks, PIT tags can be read by antenna arrays, as illustrated here. These systems are composed of a transceiver, two antennas spanning the width of the water column, a method of data collection (such as a laptop), and a power system. Passive tags do not contain an internal battery, but obtain power inductively from the electromagnetic field generated by the antenna. The two antenna are set up around 2-3 meters apart, one upstream and one downstream, so that not only will the antenna pick up which fish is swimming in the area, but also will record directionality that the individual is swimming based on which antenna is pinged first.
Sources:
Bond, R.M., Nicol, C. L., Kiernan, J. D., & Spence, B. C. (2018) Occurrence, fate, and confounding influence of ghost PIT tags in an intensively monitored watershed. Canadian Journal of Fisheries and Aquatic Sciences.
Ficke A. D., Myrick, C. A., & Kondratieff M.C. (2010) The effects of PIT tagging on the swimming performance and survival of three nonsalmonid freshwater fishes. Ecological Engineering 48: 86-91. doi:10.1016/j.ecoleng.2011.07.011
Prentice , E. F., Flagg T. A., McCutcheon C. S., & Brastow D. F. (1990) PIT-Tag monitoring systems for hydroelectric dams and fish hatcheries. American Fisheries Society Symposium 7: 323-334.
Smyth, B. & Nebel, S. (2013) Passive Integrated Transponder (PIT) Tags in the Study of Animal Movement. Nature Education Knowledge 4(3):3
Gibbons, W.J. & Andrews, K.M., (2004) PIT Tagging: Simple Technology at Its Best, BioScience 54 (5): 447–454, https://doi.org/10.1641/0006-3568(2004)054[0447:PTSTAI]2.0.CO;2
Juvenile Coho Salmon (Oncorhynchus kisutch), watercolor and marker, 2018
