Help us monitor brown trout by joining our redd surveys!

This winter the Chilterns Chalk Streams Project (https://www.chilternstreams.org/) are running redd surveys to monitor brown trout populations on the Chess and Misbourne, and we need your help!

'Redds' are spawning nests made by female brown trout in gravel bed rivers, creating a clear scrape to lay eggs. The counting of redds is a great technique to infer the health of the breeding brown trout population.

Last year we had good success surveying redds on the Chess - click here to see the results (https://www.chilternstreams.org/2026/05/22/new-brown-trout-breeding-survey-results-out-now/) - recording 191 redds. This data is being used by CCSP to improve brown trout habitat and also feeding in to Environment Agency analysis of trout population changes.

This year we want to repeat the survey to track population changes over time, and expand the surveys to the Misbourne

Photo highlighting a redd

Redd survey training day

What is a redd survey like?

The surveys will involve walking a stretch of the river assigned to you, and doing a visual check from the banks to record all of the redds that you see. You will take a photo and record any redd sightings on our simple Survey123 form.

Ideally, you will walk your river section fortnightly across the breeding period (November-February), to record the appearance of new redds. You will be surveying independently so can do your survey walks at any time that suits you. If this is not feasible, a couple of visits in peak breeding period is still useful.

Who can get involved?

This training is free and open to all - you do not need any prior knowledge of trout or be able to identify a redd - we will teach you from scratch!

The intention of the training is to recruit volunteers to survey on either the Chess or the Misbourne, so please sign up if you are interested in surveying on one of these rivers.

Training Day Details

This training day is delivered by Martin Van Heerden, Fisheries Technical Specialist at the Environment Agency, teaching redd ID and field skills. Paul Jennings, River Chess Association, and Iona McMillan, Chilterns Chalk Streams Project, will provide instruction on the survey plans for the Chess and Misbourne.

Itinerary:

9.45 -11.00 - Indoor Classroom - Presentation on Redd ID and Surveys

11.00-11.15 - Tea break

11.15-12.00 - Fieldwork - Practise Redd Surveys out on the River

12.00-12.30 - Assigning survey stretche

Meeting location:

Barn Meadow Community Hall, School Ln, Amersham, HP7 0ES, England

There is free parking available in the car park next to the community hall, see the below map:

If you have any questions about the day or the surveys, please email chalkstreams@chilterns.org.uk

Description supplied by the event organiser.