During our survey work, we are trying to develop and test a simple 1-5 scoring system for saying quickly how much rock cover there is in the bottom of a watercourse. Very briefly, the more cobble-sized stones that are present, the higher the holding capacity for young fish. Siltation and sedimentation covers up rocks and reduces habitat quality for fish by burying the stones behind which they like to hide. Salmon parr especially are very vulnerable to predation if they have no cover.
There follows some examples of how different areas might be scored. We have trialled these with over 200 photos in the past and I think this will turn out to be a very useful exercise, at least for highlighting areas of concern. The scoring system encourages surveyors to think about habitat quality in the watercourses all the time. After 1000 miles of survey work, we will have given it a good testing and will know if there is anything of value here or not.
This is score 1, watercourse is dominated by sand or sediment, with very few, if any rocks protruding through it.
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