PIT (Passive Integrated Transponder) tags have been used for over thirty years to permanently identify individual animals and it´s being used to monitor wild fish in a variety of ways.

Beginning with fisheries studies, the use of PIT tags has expanded to include bats, reptiles, amphibians, birds and many other animals and objects. Decades of studies involving capture-recapture, movement, abundance, survival and recruitment have confirmed that PIT technology is a reliable and effective method of identifying and monitoring individuals over long periods of time. PIT tags allow researchers to safely mark animals internally without altering external appearance. In almost all cases the tag will stay with the animal for its entire life cycle. The small size of PIT tags virtually eliminates negative impact on animals with little or no influence on growth-rate, behavior, health or predator susceptibility. Automated monitoring systems that record temporal and spatial information make recapture unnecessary reducing handling time and stress to the animal. Biomark provides a variety of durable readers and antenna types for use in remote monitoring locations.

VAKI together with Biomark aims to give researchers very specific information about individual fish and their behavior. The Riverwatcher measures and counts each fish and now the product can read PIT tags and incorporate this vital information with the Riverwatcher software to identify individual fish within the group. This means that a researcher can go through the data and identify a tagged fish, connecting this information with other critical data.