Did you know that European eels – previously an abundant denizen of UK waters, are now classified as critically endangered on the IUCN red list of threatened species?
As a key member of the food web, these extraordinary creatures are vital to maintaining the ecological balance in aquatic environments. But they are in crisis. Through monitoring of the upstream eel migration in freshwater, the Zoological Society London (ZSL) and many others have found that recruitment into rivers is only at about 10% of what it was prior to the 1980s – a truly shocking statistic.
As with most species declines there are a number of factors behind the eel’s disappearance. These include over-fishing (including the booming illegal trade in elvers – young eels), the loss and pollution of habitat, climate change, parasites and viruses, and barriers, such as weirs, dams and sluices. These cause river fragmentation and stop eels from reaching much of their previous habitat.
But, all is not lost!
After receiving funding from the Green Recovery Challenge Fund, Thames Rivers Trust is working in partnership with Rivers Trusts Action for the River Kennet, South East Rivers Trust and Thames21; as well as working closely with ZSL and Thames Estuary Partnership to develop a methodology for identifying and assessing the obstacles preventing the migration of the eels up our rivers. The results will inform much needed changes to the river environment.
The project, which began in December 2020 and runs to March 2022, focuses on 5 rivers which previously had healthy populations of eels – the Kennet, Pang, Mole, Ravensbourne and Upper Brent.
Dedicated project officers (POs) are training up local members of the community to be citizen scientists at these rivers. As well as teaching the ‘eel force’ about the plight of European eels, they’ll also learn how to gather robust data by using the recently updated River Obstacles app, developed by Natural Apptitude. This is a partnership between the Environment Agency, the Rivers Trust, ZSL, TEP and the River Restoration Centre.
The ‘eel force’ go out as a team on specific days, walking the riverbanks and using their ObstacEELS training to collect vital obstacle data. They carefully assess the ‘passability’ of each man made structure in the river channel. By mid-October 2021, POs, with volunteers, have covered the majority of these rivers, ground truthing old data and collecting supporting imagery – all which has been done using the River Obstacles app. The app also records the route people take when surveying, so that in the future we can see which sections of river have been surveyed. This will enable limited resources to always be focused on unsurveyed areas.
The app uses Coreo behind the scenes. This enables the project to easily review all the data to ensure accuracy and allows for the removal of duplicates. The ‘cleaned’ data are then used to create a ‘live’ Fish Migration Roadmap of the obstacles. All of these data will feed into the Environment Agency’s Thames River Basin Eel Management Plan, the main focus of which is to improve the area’s rivers for eels.
Without the use of an app, this project would still be using traditional methods such as pen and paper to record this data.
“Redeveloping the River Obstacles app has ensured the success of this important citizen science project. The app has meant that we are able to increase the amount of data we are able to collect and our citizen scientists have all the resources, like ID guides, that they need. The data will be used to improve the River Obstacles dataset, enabling the EA and other organisations to accurately prioritise obstacles for removal or fish passage. The Natural Apptitude team have made whole process very simple and easy for us. They combine professionalism with a friendly and approachable attitude. They’re always on hand to answer our questions and advise us on the best approach. You don’t just get an app but a working relationship that adds real value to your project.”
“The launch of the app has been a huge success! Volunteers using it are finding it so much more efficient both for them and the project. It is enabling us to gather accurate data in a simple way.”
Do you have a citizen science project in the works and want to learn more about how software can simplify and streamline the project? Get in touch with us today at email@example.com.
This project is funded by the government’s Green Recovery Challenge Fund. The fund is being delivered by The National Lottery Heritage Fund in partnership with Natural England and the Environment Agency.