The Environment Agency is deploying a one-of-a-kind electro boom boat to conduct essential electric fishing surveys along the River Thames, stretching from Iffley Lock to Teddington Lock.
Each year in July, agency teams head out after dark to monitor the state of fish populations in the Thames. These night-time surveys collect data on fish length and scales, which help build a year-on-year picture of fish growth and overall health.
Electric fishing involves creating an electric field in the water to temporarily attract and immobilise fish. The Agency’s ‘Thames Trout’ boom boat, fitted with the largest underwater electrodes in their fleet, can cover a wide section of the river, making surveys faster and more efficient.
When activated, these electrodes stimulate a fish’s nervous system, causing it to swim toward the operators or become briefly immobilised, allowing officers to net them easily. The fish are then placed in aerated holding tanks where they recover quickly before being identified, measured, and safely returned to the river.
Environment Agency team leader Jonathan Baxter said:
“We undertake annual fish-monitoring on the Thames and its tributaries. We have a statutory duty to maintain, improve and develop fisheries, and the Thames Trout makes what could be a tricky process an absolute doddle.
Surveys such as these provide extremely accurate data from our principal fisheries and can detect trends linked to factors such as climate change.
The Environment Agency tends to begin these surveys at dusk when the waterway is quieter, allowing it to perform its work without interruption by other river users. The night also tends to produce better results as the fish rise in the water so they can be more easily caught”.
Jonathan Baxter added:
“More than 6,200 fish were caught in the 2024 survey between Iffley and Benson with results showing an abundance of healthy fish.
We’ve surveyed more than 10,000 this year and despite the recent dry weather, we have seen no significant impact to the Thames fish population, although as with any dry weather event, anglers should be mindful of the fish they are catching as some species may need a longer recovery period in extreme heat”.
The Thames continues to offer fantastic opportunities for anglers of all ages to enjoy one of the UK’s largest rivers. However, anyone aged 13 or over must have a valid fishing licence to fish for salmon, trout, eels, or other freshwater species. Licences can be purchased online at [www.gov.uk/fishing-licences/buy-a-fishing-licence](https://www.gov.uk/fishing-licences/buy-a-fishing-licence) or by phone on 0344 800 5386, with concessions available.
Rod licence fees contribute directly to the sustainable management of fisheries. Enforcement officers, alongside angling clubs, the Angling Trust, and local police, routinely patrol rivers, lakes, ponds, and canals to tackle illegal fishing.