The Environment Agency in England and Wales now requires all farmed brown trout stocked into rivers and some lakes to be infertile (triploid). These regulations were put in place in January 2015. Details are on the EA website archive — click here.
The Scottish Government has a simlar policy — details are here.
This web page contains information on the topic of stocking farmed trout and includes videos and case studies from fishing clubs.
The Wild Trout Trust is often asked for advice relating to the introduction of farmed trout (stocking) to rivers. Please do contact us for informed advice and comment; we often hear the same reasons given by different people for wanting to continue to stock rivers with fertile farmed brown trout. Click here to download a PDF of common questions and answers.
We have produced a position statement with a list of references, and also a concise summary document to help people make an informed decision about stocking and the protection of wild brown trout.
The document was prepared by Dr Paul Gaskell with assistance from other WTT staff and our volunteer Advisory Panel, and published in May 2012.
Wild Trout Trust — View on Stocking and Rationale
Wild Trout Trust — View on Stocking — Summary
The video below, Improved Trout Stock Management includes suggestions about how to improve your wild trout fishing opportunities:
Our experience is that many fisheries can become wild trout fisheries, and this is achieved by spending money on habitat improvement rather than farmed fish for stocking, and using catch and release. The Wild Trout Trust will help you to find and use those opportunities.
However, we do recognise that some clubs feel they absolutely must stock to overcome a complete lack of habitat or to support catch and kill angling. In this case, our advice is :
- Make adult habitat as good as possible in order to retain stock fish on your reach
- Use marked sterile (triploid) stock fish
- Set realistic numbers for stocking – no more than 1 fish per 50m2 of total river area.
- Stock small batches of fish frequent intervals.
- Have designated stocked areas that cater for members who wish to catch and kill fish
- Maintain catch and release, wild fish only reserve sections
- Remove as many stock fish as possible at the end of the season. Do not feed fish over winter.
- Team up with other clubs on your river and have a ‘joined up’ stocking policy
A number of angling clubs the Wild Trout Trust have worked with have taken the decision to cease stocking or reduce the numbers of fish introduced to their rivers. We asked them to provide case studies of their experiences describing how and why they took the decision and what the results have been. Click on the links below for each case study (pdf documents or videos).
River Nidd, North Yorkshire - Nidderdale Angling Club
Afon Clwyd, North Wales - Denbigh & Clwyd Angling Club
River Leven, North Yorkshire - Hutton Rudby Fly Fishing Club.
River Monnow, Monmouthshire / Herefordshire - Tregate Angling Club
River Ribble, Lancashire. Three 5 minute YouTube videos of a presentation by Neil Handy at the 2015 WTT Annual Get Together covering the experience of reducing stocking on the River Ribble. Section 1. Section 2. Section 3.
Salisbury and District Angling Club. A large club of 2,200 members with extensive chalk stream fishing in Wiltshire. This is a video of a talk given by Andreas Topintzis at the 2016 WTT Annual Get Together. An interesting (and amusing) story of big changes to a large club.
River Wharfe, North Yorkshire - Ilkley Angling Association
An academic paper which looked at the impact of stocking sea trout in Shetland. See this news item ‘Shetland stocking does not make for more trout’ and the full paper.
The history, science and future of stocking by Kyle Young. This article was first published in 2021 in ‘Wild Fish’ by Salmon and Trout Conservation.
See below this excellent video from Montana: Stopping stocking — the experience 40 years on.
The full length document ‘Wild Trout Trust — View on Stocking and Rationale’ contains an extensive list of scientific references. Many of these are available if searched for using an internet search engine or British Library On Demand.
The following articles on the subject of stocking, were written by Dr Paul Gaskell for Trout and Salmon magazine:
- Let Them Get On With It (4 Mb) — Wild broodstock and fry stocking: all its cracked up to be?
- No Sex Please - We’re Triploids (3 Mb) — the benefits of infertile stock fish
- To Stock or Not to Stock (4 Mb) — the pros and cons of introducing fish
Below are several articles relating to stocking, previously published in the WTT magazine Salmo trutta:
- Native broodstock: ‘Trout stocking – where do we go from here?’ Andy Thomas. Click here to download.
- Science roundup: Trout genetics. Click here to download.
- Science roundup: Origins of brown trout diversity. Click here to download.
- Article by John Aston with his thoughtful views on ‘the great stocking question’
- Environment Agency (England & Wales) National Trout and Grayling Fisheries Strategy, 2003. PDF
- Environment Agency (England & Wales) Trout Stocking Policy leaflet, 2009. PDF
- Professor Andy Ferguson’s report for the EA, ‘Genetic impacts of stocking on indigenous brown trout populations’, 2006 PDF
- Scottish Natural Heritage Commissioned report no.513; Guidelines for stocking of fish within designated heritage sites PDF
- Salmon & sea trout: To stock or not? A publication produced for the Scottish Executive by FIsheries Research Services PDF
- Wild Broodstock Schemes: A Good idea? PDF