Summary: This plain English factsheet outlines the work done by the EPA monitoring aquatic invertabrates in our rivers.
Aquatic invertebrates are small animals that lack a backbone and live under water. In our rivers they can be found attached to, and amongst, stones and gravel, logs, leaf material and vegetation, or burrowed into the bottom sand and mud. They include juvenile (larvae) and adult insects, crustaceans, mites, snails, mussels, leeches, and worms.
Aquatic invertebrates inhabit all rivers from small mountain streams to large systems entering the sea. They are food for fish and aquatic birds and are vital for healthy rivers. Most invertebrates are present in rivers all year round and are easy to collect and they are used as ‘indicators’ of pollution in rivers and lakes around the world.
https://www.epa.ie/media/epa-2020/monitoring-amp-assessment/freshwater-amp-marine/River-Monitoring-â-Aquatic-Invertebrates.jpg