Does it work?

During our ISAC project we set out to restore over 32km of the Irfon’s important nursery streams. However, we didn’t get to restore the entire catchment. In some cases treatment wasn’t necessary, in other sections we couldn’t get permission or simply couldn’t find the owner.

Environment Agency Wales (now Natural Resources Wales) undertook the electrofishing monitoring. Before the sites for restoration were chosen, they set up 40 monitoring sites, 31 in our area of activity. Thus the selection for the monitoring programme was quite independent of where the work was planned.

The project started in 2010 and by the end of 2013, we had a series of results from reaches that had been extensively restored, some simply protected by a fence and a third category of reaches that, for whatever reason, were not treated in any way. The graph on page 10 shows how this work improved fish numbers: 18 control sites only marginally improved while the sections receiving the more intensive care increased their fish populations the most but from, as expected, a lower baseline. Crucially, all the sites within a restored reach increased showing that it was higher fish numbers rather than migration from non-improved sections.