The Effects of Weirs on Japanese Gigantic Salamanders

In Totori, Japan, there are a lot of weirs in the Nawa River Basin. Weir is just a smaller dam and it is used not just for flood control but also to irrigate fields. For a Japanese giant salamander, these are massive artificial barriers,. So salamanders, you know, their natural behavior is to move along the river. And so when you have these weirs and dams as well in the river, they can maybe move downstream. But then the problem is that they can't move back up because they physically can't climb over or around them.