Herting

Out migration is the journey many fish make from rivers out into the open ocean. ​ Eel, Atlantic Salmon, and Sea Trout are among those making the arduous migratory passage. For each, down stream passage to the ocean is an important part of their life cycle and a crucial step in their journey to spawning.
The Falkenberg Energy Herting hydropower dam, located on the Ätran river in Falkenberg, Halland in southern Sweden, bears witnesses each year to the out migration of these species. ​ ​Atlantic Salmon and Sea Trout pass through each spring, while the eel migrate in the fall. ​ ​In late September of 2020, we came to see the out migration for ourselves, installing our FishL™ Recognition system in the downstream fish bypass shoot of the dam.
The implementation of European fish passage initiatives has brought an increased demand for accurate and accountable monitoring of upstream and downstream fish passage. This was our first opportunity to utilize the FishL™ Recognition System for downstream monitoring and the first European installation of this safe, autonomous, volitional, monitoring system.
The FishL™ Recognition system functions so that when a fish enters the system, a sensor is triggered. The sensor activates six cameras positioned at three fixed angles to simultaneously take three exposures in quick succession as the fish slide through the system in less than 0.5 seconds. All 18 high-definition images are digitally captured as permanent records associated with the date and time of fish imaging. The images are then processed in real time to computationally calculate the fish size, (length and girth) and speed through the system.
The system has already been in operation for around one month this fall, collecting Adult Eel images and size data. ​ ​In spring of 2021 it will be gathering data in order to monitor the Atlantic Salmon and Sea Trout out migration populations at Herting.

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