Half our rivers are choking

Nearly half of all river sites tested by volunteer anglers are recording nitrate levels harmful to aquatic life, according to the Angling Trust’s third annual water quality report – the largest citizen science dataset of its kind collected in UK rivers.

Analysis of more than 12,000 samples by Isla Thorpe of the University of York found that 49.93% of monitored sites showed environmentally harmful nitrate concentrations, with the proportion breaching safe limits rising every year since monitoring began. More than 40% of sites also failed phosphate standards, and the proportion exceeding ammonia safety thresholds has risen from 3.58% to 4.49% over three years.

The picture is particularly troubling for chalkstreams. Applying Natural England’s phosphate targets, 91.5% of samples from the Hampshire Avon breached safe limits and 85% from the River Meon. Average nitrate levels on the Test and Itchen exceeded ecologically safe thresholds in every single month of the third year of monitoring.

Alex Farquhar, the Angling Trust’s freshwater campaigns officer, said the findings were unambiguous. “Excess nutrients on this scale translate into algal blooms, fish without enough oxygen to survive, and anglers on the bank wondering where the fish have gone,” he said.

Over 800 volunteers have contributed more than 4,000 hours to the network since it launched in 2022.