Another photograph showing sea trout pretending to be sardines, packed tightly into a sunken tree in the river Cothi. This is very common behaviour in the Welsh rivers I dive, especially in low water conditions.
I have seen it several times. Cover is a real problem here for them. Adding more cover would be a great idea.
the largest known woody deposit, covering 51 square kilometers (20 square miles) of the Mackenzie River Delta in Nunavut, Canada, and calculated that the logs store about 3.4 million tons (about 3.1 million metric tons) of carbon.
This is how all forest rivers used to be until humans ripped out jams and made ditches in their place.