On 14 and 15 May 2026 the SturNet team in Türkiye placed acoustic receivers in the Sakarya River and tagged ten sturgeon. The work is part of building permanent monitoring of the river — not a one-off count, but a network that will record the movement of the fish over the coming months.
How acoustic telemetry works
The method is simple in design and difficult in execution. The fish carries a miniature transmitter that sends an acoustic signal underwater. Along the length of the river stand receivers that record every passage within range. From those records, accumulated over months, one can read where the fish move, which stretches they use, and how many of the tagged animals remain alive.
Before the deployment the team carried out a range test — a check on how far the signal can be read reliably, which determines exactly where each receiver should stand. The receivers sit on weights built for the purpose, and a local fishing boat helped to lower them.
Who took part
The work was coordinated by Elif Damla Arısan. In the field it was carried out by Aytaç Özgül, Altan Lök, Evrim Kurtay and doctoral researcher Zeynep Demirel. The weights for the receivers were built by Prof. Dr Mehmet Salim Öncel of the Department of Environmental Engineering, and staff of the Bolu Provincial Directorate of Agriculture and Forestry provided support on site.
What telemetry can and cannot tell us
There are no results yet, and none should be expected soon — this is the beginning of the monitoring, not its conclusion. Ten tagged fish are a small sample and do not allow any estimate of the population. What telemetry gives is something different and hard to obtain by other means: evidence of where individual animals actually move and which stretches of the river they need. That is precisely what is missing when a particular stretch has to be defended against a particular intervention.
Photographs from the field are published on the official project website — sturnet.eu.