Fish ladders provide upstream passage for migratory fish over dams, weirs, and other barriers in waterways throughout the world. While these passage structures play an important role in helping fish access habitats they otherwise could not, fisheries biologists also value them for another reason: ladders are often perfect places for installing fish counting stations. Streams with migratory fish populations tend to be too wide for counting fish effectively, especially with an automated system. Ladders, on the other hand, are often narrow enough that just a few fish can pass through a given point at a time, making it easier to count them automatically. Considering the prevalence of fish ladders around the world, you would think many turn-key solutions exist for fish ladder monitoring needs. However, our FABLAB technicians quickly discovered that ladder-ready automated fish counters are not easily available, so we turned to our trusted alternative – and decided to build one ourselves.
With no off-the-shelf solutions available to meet our needs, we ended up with a completely custom-built system, down to cutting the glass lenses for the camera housings and wiring the plugs. After some painstaking effort, we’ve developed a system that meets our standards and is now deployed in the field, ready to collect video of migrating salmonids. The ladder in this ephemeral system has not had much water in it during the last few dry weeks, but things are likely to get flowing again given the most recent bout of rain. We’re excited to see the camera system get put the test, and are already looking forward to exploring new applications for our latest fish monitoring technology.