What’s down there? Surveying Broads fish stocks with the Environment Agency:
For anglers, one of the most exciting aspects of fishing in the Broads is never quite knowing what’s down there! But when it comes to managing fish stocks, this can also be one of the most difficult aspects. Fisheries Technical Specialist Steve Lane from the Environment Agency sheds some light (or should we say sound) on how the Fisheries team is finding out what’s going on under the surface…
‘The presence of a healthy, thriving fish population is vital for angling in the Broads. Fish also play an important role in the ecology of the Broadland waterways. So understanding the current state of fish stocks is really important, not just to ensure good fishing, but also to maintain and improve the health of the water and its wildlife. Broads anglers also contribute in the region of £100 million annually to the local economy, so good fishing makes sound economic sense too!
The Fisheries team is currently using a hired Broads cruiser to undertake hydroacoustic fish surveys of the tidal rivers. A specially-modified arm has been developed to clamp onto the bow of the boat. Mounted onto this is a sounder unit, which emits sound waves at pre-determined frequencies into the river. These sound waves bounce off the swim bladders of fish and are reflected back to equipment in the survey boat where they can be recorded and analysed. As we move along the river, we can tell the numbers, sizes and relative positions of fish in the sonar beam. Special water quality monitoring equipment is also being deployed, which can check for signs of pollution along the river while the survey is in progress. We can cover stretches up to 40km in one night, providing a wealth of information on fish density and distribution and water quality throughout the river that would not be possible with traditional sampling techniques.
While the surveys are running, we are working with angling clubs to check representative samples of fish caught during fishing matches along the tidal rivers. A selection of fish are collected, measured and scales are removed to check species, ages and growth rates. Fisheries officers also check the overall health of the fish before they are safely returned to the river.
We are also using the boat to undertake specialised high resolution sonar surveys of some of the Bure Broads, looking at fish movements and behaviour. We are studying how fish use different habitats at different times of the year, particularly for spawning. If we can understand which habitats are important, we can take action to protect and improve areas that are contributing to the next generation of fish stocks.
At present, fish stocks appear to be very favourable across the Broads, with high fish densities being recorded in hydroacoustic surveys in recent years. This reflects excellent pleasure and match fishing returns reported over the same period. Broads fishing matches are currently attracting anglers from all over the country and more and more anglers are attracted to the Broads by the potential to catch massive specimens of species such as roach, bream, rudd, tench and perch’.
For more information on fishing in the Broads and how the Environment Agency’s fisheries surveys are being used to maintain, improve and develop angling, please visit the Broads Angling Strategy Group website: http://basgonline.org/