Fish survey results: 2020


The River Derwent fish and habitat survey project is now in its sixth year. The project aims to complete yearly fish and habitat surveys in order to determine the health and state of the catchment of the River Derwent and its tributaries. 

The data collected is used to: 

  • monitor the inter annual variations of the juvenile populations of Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) – collectively referred to as salmonids 
  • determine underperforming areas in order to direct where habitat improvement projects are needed
  • monitor the effectiveness of previous habitat improvement projects
  • locate ecological threats such as invasive species 
  • build up a database to ultimately determine long-term trends

During the 2020 survey season, WCRT conducted surveys at 162 sites. In total, 4,786 salmonids were recorded, of which 3,215 were trout and 1,571 were salmon. These numbers can be broken down further into fry and parr numbers; 2,580 were trout fry and 1,372 were salmon fry (fry being less than a year old); and 635 were trout parr and 199 were salmon parr (parr being young fish over a year old). Of the total 162 sites surveyed, 130 sites (80%) had trout fry present and 77 sites (48%) had salmon fry present.

In order to undertake the surveys during the COVID pandemic, a small team was set up (unfortunately our usual method of working with lots of different volunteers was not possible). External support was provided by a Lancaster University funded intern and two WCRT volunteer interns. Without this assistance the project would have been unable to go ahead, and we are grateful for their dedication during difficult times. 

As well as the team, we’d like to say a massive thank you once again to the many landowners who gave us permission to access their land to get to the rivers.

Full report and raw data 

You can also explore the 2020 results in our interactive maps:

Photo Gallery


Name Type Size
2020 survey report pdf 4.47 MB
2020 raw data xlsx 125.15 KB