Otters as biomonitors of water quality in the Ribble Valley

Student Spotlight - Lucy Grinstead

Master's Research at Lancaster University

Email: lucygrinstead@hotmail.com   LinkedIn: https://www.linkedin.com/in/lucy-grinstead-92a6651b3/ 

Project Summary

Eurasian otters (Lutra lutra) are the only species of otter located in the United Kingdom and are protected under the Wildlife and Countryside Act 1981. In the 1950’s otter numbers experienced a decline thought to be the result of organochlorine contamination (pollution from pesticides) and habitat destruction resulting in few remaining individuals, especially in the northwest of England. The aim of my master's research is to improve our understanding of the spatial distribution of the Eurasian otter within the Ribble Valley as this is an area that previous studies, such as those conducted by the Cardiff University Otter Project, have found to be low in numbers. Additionally, my research helps agencies such as the Ribble Rivers Trust to continue the protection of such species.  

One aspect of my research involves the collection and chemical analyses of otter faeces, known as spraints. Otter spraints have been used previously by studies across Europe (e.g. in Spain (Baos et al., (2022)), to observe the volume of heavy metal contamination in various catchments. Such methods consider the otter as a ‘biomonitor’ for the health of the river catchment as they live and consume species that reside in the waterways. Biomonitors are organisms that accumulate contaminants in their tissues so can be used to estimate a relative measure of contaminants in the environment over time, thus providing quantitative information on the quality of the environment. Using otters as biomonitors not only allows us to understand the level of heavy metal contamination within the water and sediment, but also the volume of bioaccumulation within the food chain and potential risks that the levels they are consuming could have. This information can be used to argue for the need to remediate and protect waterways especially in an area such as the Ribble Valley that has a rich industrial history making it likely that historical contamination is still present.  

Creating novel ways to monitor river health is critical in a time when the Environmental Agencies efforts to sample water quality has reduced by over 50% in the past 10 years. As a result, we know less about our waters in a time where none of the rivers in the UK reach ‘good’ under the Water Framework Directives standards. Global warming also increases the likelihood of further declining water quality with lower water levels concentrating the water contamination. In addition, global warming can alter parameters such as water pH, which could draw out contamination that has been locked up in the sediment making it more available to the species within and around these water bodies.  

Experimenting with biomonitors in such a way as my study does will hopefully advance further method development and encourage agencies to experiment with biomonitors as an alternative method to testing river water quality. Using biomonitors provides a method that can be cheaper and less time-consuming but also has the ability to grasp the general public’s attention. Hopefully this can also increase citizen science participation with the use of a charismatic species and an easy identification method.

Scientific Poster

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Acknowledgements

Special thanks to Leanne Tough at the Ribble Rivers Trust for their support and help with identifying potential locations. Thanks to Kevin Jones for his support and ongoing supervision throughout this project. Finally, a big thank you to John Crosse for his support in the laboratory.