RFID-Technology

Since the mid-1980s, RFID technology (Radio Frequency Identification) using animal transponders, known as PIT-tags (Passive Integrated Transponders) has provided a very gentle marking method, which is used for zoo-, domestic-and livestock animals. Even fish can be individually marked and identified by handheld readers or stationary antenna without direct contact after they are initially tagged.

11 x 2 mm, 23 and 32 x 3.9 mm sized PIT-tags

antenna charges transponder by inductance

principle of RFID-operation
(click to enlarge)

activated transponder sends its ID-code to antenna

Because a PIT-tag does not require an energy source, the mark lasts the lifetime of the animal and beyond. Moreover, the small, bio-glass capsuled and < 1 gram PIT-tags are gently applicable, well-tolerated, and affect neither the behavior, nor the reproduction of tagged specimens. Used in the United States and Canada for more than 20 years, RFID systems are increasingly being used in Europe for outdoor surveys too. However, since the range of the antennas is limited, RFID systems are used only in smaller creeks and/or antennae are installed at bottlenecks e. g. in fish ways.

The Institut für angewandte Ökologie GmbH has worked with both RFID systems including FDX (full duplex) and HDX (half duplex) since the early 1990s. We developed the technical knowledge, such as software tools to drive up to 36 antennas and a databank for administrating the ID-Codes of the transponders and individual information, as well as for recording and analyzing detections. We are able to manufacture and tune HDX-antennas of all sizes (up to 30 square meters or 15 m long) and install reliable working systems for long-term operation under outdoor conditions.

Finally, we have tagged about 100,000 fish of different species in the rivers Elbe, Wupper, Diemel, and Rhein to examined their small and large-scale migration patterns and the effectiveness of fish passes

Location of transponder inside a fish

Row of RFID frame antennas

Reference projects

2017 - 2019: Monitoring the fish migration in a 26 km long river course in the Rhine along the German-Swiss border over 8 fish passes at 4 weirs by using HDX-technology.
2016 - 2017: Basic study on fish passages at diversion hydro power plant on the river Diemel
2014 - 2018: Monitoring the fish migration in a 60 km long river stretch in the river Wupper by using HDX-technology.
2009 - 2018: Monitoring the upstream migration over the old natural like fish pass channel and the new double slot fish pass at the weir Geesthacht at the river Elbe with HDX-technology.
1994 - 1996: Monitoring two fish passes at the rivers Sieg and Dill with FDX-technology

Publications

SCHWEVERS, U. & B. ADAM (2018): Zur Sackgassenwirkung von Ausleitungskraftwerken für stromaufwärts wandernde Fische. - Wasser & Abfall 20/7+8, 67 - 71.

ENGLER, O. & B. ADAM (2014): HDX-Monitoring Wupper: Untersuchung der Wanderung von Fischen, Untersuchungszeitraum vom 31. Oktober 2013 bis 31. Mai 2014.

ADAM, B. & U. SCHWEVERS (1997): Zur Funktionskontrolle von Fischwegen - Einsatz automatischer Kontrollstationen unter Anwendung der Transponder-Technologie. - DVWK-Schrift 119, Bonn (Wirtschafts- und Verlagsgesellschaft Gas und Wasser GmbH), 100 S.