PIT Telemetry

PIT tags do not have a battery but a coil and are therefore called passive rather than active. Since the tags are passive, they can last a lifetime. Tags for PIT telemetry range from 12 mm to 32 mm. The size of the tag that will be used depends on the size of the fish species. The PIT tag is inserted into the abdominal cavity of the anaesthetised fish using a hollow needle or via incision.

Before tagging the fish, PIT antennas are placed at a natural bottleneck. The antenna consists of a durable plastic frame into which an insulated copper wire is incorporated. In this way, each antenna can be made in different shapes and sizes. Each antenna has a tuner box that ensures the antenna functions optimally for detecting PIT tags. A tag, which comes within range of the antenna, is charged by the magnetic field of the copper wire. The charged tag sends its unique code, which is received by the antenna. The whole cycle takes place within a fraction of a second. The signal is transmitted via cables to the reader, which stores the detection, time and date. The PIT telemetry data can provide insight into fish behaviour and distribution.

Each PIT station contains a reader, a wireless internet module (WIM) and a power supply. The reader can simultaneously monitor four antennas. The detections from the antennas are stored in the reader and then sent via the WIM to the cloud. The storage capacity of the system is virtually unlimited. The WIM ensures that every 24 hours the detections are sent to a cloud for further processing. Each detection contains the unique PIT tag number, antenna number and time/date of the observation. The PIT stations can be powered by a grid connection or a solar panel combined with batteries.

The detections in the reader's database are uploaded every 24 hours to the VisAdviesAMF application (https://www.visadviesamf.nl/). The application makes storing, managing and visualising the PIT telemetry data easy and allows the user to access the data from anywhere.