Large eel like object in River Ness?

Something large seems to have passed by one of the underwater cameras that the Ness Fishery Board employs to monitor salmon runs. It has all the appearance of a large eel. It's a bit indistinct due to our helpful peaty water but it looks alive and big. Not quite a 30 footer but easily outsizes the salmon in the foreground which gives the impression of backing off from this object before moving back in.

Assuming this was taken at the weekend when we had a lot of rain and rivers were in high spate, something seems to have taken advantage of this high water level. I assume from the motion of particles in the water and the salmon that the flow is from left to right indicating Loch Ness is to the left and the Moray Firth to the right. In other words, this object is heading from the loch towards the sea.