New brown trout breeding survey results out now!

A new citizen science survey on the River Chess has uncovered encouraging signs for brown trout, with 191 redds (spawning nests) recorded during winter 2025/26. Led by the Chilterns Chalk Streams Project in partnership with the Environment Agency and the River Chess Association, the pilot recruited 15 trained volunteers who carried out 76 surveys between November and March, contributing around 260 hours of effort. The findings show trout were breeding along a wide stretch of the river, from Chesham to Rickmansworth, with peak activity recorded between December and February.

The survey is helping identify important spawning habitats to protect, as well as areas where barriers or poor habitat may be limiting breeding success. It also demonstrated the value of community monitoring, with volunteers growing in confidence and skill over the season.

The project now plans to continue surveys on the Chess, expand to other rivers such as the Misbourne, and use the results to guide future river restoration work. We are also keen to continue working with partners including the EA to contribute to wider development of citizen science redd monitoring techniques.

To find out more and see all of the results including maps of where redds were recorded, download our report below.

Interested in getting involved? We need more volunteers, training will take place in late Autumn so why not get involved in the upcoming surveys! Email us at chalkstreams@chilterns.org.uk or sign up to our newslettter to keep up to date.

Led by the Chilterns National Landscape, the Chilterns Chalk Streams Project is a partnership of statutory agencies, local authorities and voluntary bodies committed to conserving the chalk stream environment