2026/07/10 by Jan Droll, Christoffer Nagel, Joachim Pander +1
Environmental Science · Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Fish Ecology and Management Studies #Aquaculture Nutrition and Growth #Reproductive biology and impacts on aquatic species
paper · doi:10.1016/j.fishres.2026.107808
Passive integrated transponder (PIT) tags have become a popular tool for mark-and-recapture studies, and the evaluation of spatio-temporal habitat use in fish, including the passage of technical structures. Their increased popularity makes studies about their potential limitations related to their positioning and physiological effects on growth and survival necessary. We evaluated the impact on growth and survival of three different 12 mm PIT tag application positions on rainbow trout ( Oncorhynchus mykiss ): next to the dorsal fin, intraperitoneally, and in the pelvic girdle. Additionally, we assessed the detection probability of the tags at various distances from a pass-over antenna. Our findings indicate that the different tagging positions did not affect mortality (0% for all treatment groups), growth in length or weight over the 35-d period after tagging. The dorsal tagging position had the highest retention rate of 100%, followed by tagging of the pelvic girdle (97%) and intraperitoneally (96%). At 20 cm fish-to-antenna distance detection probability was 100% for all tagging positions; however, this probability decreased with increased distance. At a 50 cm fish-to-antenna distance, the detection probabilities for the pelvic girdle and intraperitoneal positions were 97% and 93%, respectively. In contrast, the dorsal tagging position experienced a significant decrease to 43% when the antenna was in a pass-over orientation. Overall, while the various tagging positions did not have any physiological impact on adult rainbow trout, consistent with previous studies, a ventral positioning of the tag instead of an intramuscular placement in the dorsal position increases detectability in pass-over antennas.