Spring 2015 saw the launch of the Salmon and Trout Conservation UK Riverfly Census. This involved taking invertebrate samples from five sites from each of the selected 12 rivers. The rivers being deliberately chosen based upon geographic and geological diversification.
Invertebrates are food not only for fish but also certain species of birds and mammals.
Understanding how and why the riverfly numbers are declining is the first step in the process of safeguarding the aquatic environment.
The Salmon and Trout Conservation UK says that Environment Agency historic data has been based upon family level and fails to address the question of abundance. S&TC UK Riverfly Census focuses on individual species and also abundance; so important as each species has specific tolerances to aquatic stresses.