The Grayling Research Trust

Angler Log Book Scheme

Information gained from an angling log book scheme is very important. It can provide vital evidence of a change in fish populations, which could be missed in electric fishing surveys. Log book schemes benefit all salmonid species (trout, salmon and grayling), and an example of the information a log book/angler return card can include can be found here. Log book schemes and angler return cards can provide a long-term assessment of a fish population, and log books record more detail than simple catch return cards. Log book schemes are successfully run by many organisations including; Eden Rivers Trust and Tweed Foundation.

This information, collected over a number of years, helps to inform and direct management of species and advance the scientific knowledge that underpins it. The Grayling Research Trust can help provide help and advice in analysing your log book returns.

Case study: Angler Catch Return Cards

There is a general consensus amongst anglers and fisheries scientists that grayling populations have suffered a decline in the UK, specifically in Yorkshire, since the 1980s.

In November 2011, an angling club in the Yorkshire Derwent kindly offered their historical records and angler catch returns to assist an ongoing investigation into the perceived decline of grayling populations in Yorkshire. Club records confirmed that there has been a significant decrease in the success of grayling anglers post 1980, irrespective of any annual fluctuations. During the same period, there has been an overall increase in the weight of grayling. Similarly, there has been a change in the number and size of brown trout over the same period, specifically the weight of brown trout began to increase in 1977.

It is possible that the reduced number of grayling and the increased fluctuations in trout numbers has resulted in larger individuals in both species, possibly related to poor recruitment in some years reducing the competition amongst individuals. This study has also highlighted the ability of grayling and trout populations to recover from relatively low numbers over a very short period of time (2-3 years).