The Grayling Research Trust                            WQR0068


Written evidence from The Grayling Research Trust


The Grayling Research Trust is a charitable body established in 1994 to promote or provide facilities for study and research relating to grayling populations and their habitats, ecology, water quality and environment, particularly with a view to safeguarding and improving the same and by the publication of the useful results of such research and related purposes.


Although we have not yet specifically commissioned studies on the monitoring, management or means of improving river water quality, we consider them to be very important topics and have comments to make on your first question, “What are the best indicators for river water quality that could be used as targets being developed under the Environment Bill?

Grayling (Thymallus thymallus) are a fish species of angling and conservation importance found in UK rivers, and they can be impacted by poor water quality including trace contaminants, although there is uncertainty over which materials pose the greatest threat to grayling. The presence of grayling is frequently used as an indicator of reasonably good water quality and indeed as water quality has improved in recent decades on industrial rivers, grayling have recolonised reaches from which they had been lost. This demonstrates the value of biological monitoring, to include fish monitoring.


Water quality should be such that both invertebrate and fish communities are within the range expected for an undisturbed (reference) watercourse. Biological monitoring of invertebrates and fish populations is therefore vital. There are now a wide range of indices available which assess water quality from the species and numbers of different invertebrates which are present and some allow conclusions as to what type of pollutants may be affecting the communities, which is very useful in remediation. The Invertebrate Conservation Trust is a key organisation which would be able to provide informed comment on this topic. 


It is also very important that monitoring of river water quality includes fish populations. This monitoring can vary from the monitoring of anglers catches and rapid qualitative electrofishing visits at many sites, through to fully quantitative electrofishing with frequent visits at fewer sites. Both play an important part, and both can pick up both chronic problems and episodes, or indicate a lack of problems.  The EA, NRW and SEPA should be able to provide additional informed comment on this


Biological monitoring should be carried out in tandem with chemical and physical monitoring of river water quality, preferably to nationally agreed standards, to include key trace contaminants. Regarding trace contaminants which impact fish, and which should be monitored, we should suggest that Dr Andrew Moore of CEFAS should be able to provide informed comment on this subject


Long term biological monitoring is often particularly valuable in giving insights into the pressures including water quality which drive changes in fish densities and growth rates and species composition and The Grayling Research Trust contributed funding to keeping a long term grayling study being carried out by the Game and Wildlife Conservation Trust on a southern chalk stream, the River Wylye, going and ensuring that the data obtained will be fully analysed and the conclusions published. Accessible funding for studies would be very welcome.


It is important that a high standard of biological monitoring to include fish is carried out. Chemical and physical monitoring can provide important additional information but cannot replace biological information. It is important that all monitoring is carried out to high and consistent standards, and the information obtained is properly archived, preferably with full public access online.


Best wishes


Ross Gardiner

Trustee, The Grayling Research Trust


February 2021