Was the habitat of the Wye and Usk degraded?

When we started our first surveys in the late 1990s, we found just one upper Wye tributary that had bucked the trend in the overall decline in fish numbers. Inspection showed that it conformed to the ideal – very little grazing and tree cover that allowed some light in. This was the Dernol in the upper catchment.

Most of the other tributaries were found to be no longer in a sufficiently good state to produce the densities of juvenile salmonids of former years.

The damaged habitat, in combination with heavy shading as a result of overgrown, multi-stem alders, meant that fish densities in the majority of tributaries streams were only 20% of their potential. There were other effects too: Ranunculus weed had disappeared completely from sites where it had once been abundant.

We were not surprised to find large parts of the Usk in a similar condition when we surveyed the catchment in 2004 and again in the Lugg and Arrow in 2006.