mowi electrofishing surveys

Loch Lomond Fisheries Trust strive to conserve the rivers within our catchment and understanding the fragile dynamics of our rivers is a vital part of our work. Thanks to funding from MOWI, we can use electrofishing surveys to collect data on the River Endrick, River Leven and River Blane. Electrofishing is a technique widely used by scientists and fisheries managers to survey rivers and assess the fish species present within them.

With the help of interns from the Scottish Centre for Ecology and the Natural Environment (SCENE), the LLFT team have surveyed a total of 52 sites across the Endrick, Blane, Leven and their tributaries each summer for the past 3 years. A mixture of semi-quantitative single pass and quantitative three pass survey methods were used across these sites. Quantitative sampling is the enumeration of a stock within a given site. Unfortunately, it is usually impossible to catch all fish present at a site, irrespective of the number of times a site is surveyed. Whilst semi-quantitative sampling gives a less precise population estimate, they are much faster and allow for more sites to be covered in the short timeframe we have.

Sites were chosen based off the fact they hadn’t been previously monitored and they could provide excellent spawning habitat for Atlantic Salmon and Brown Trout. This project has allowed us to detect changes in population sizes that may have otherwise gone unnoticed.

All the data recorded throughout these surveys helps inform our conservation efforts. This information provides a vital insight into the fish populations within our rivers, including species composition, abundance and health. By monitoring changes in fish populations over time, our team can make informed decisions and create science backed strategies to protect and restore river ecosystems.