Two of the most important fish species in the Broads are the Common bream and the Northern pike. Each is fundamental to Broads ecology, the first as a bottom-feeding omnivore at the base of the food chain and the second as a top predator that includes Common bream in its diet.
For generations, local anglers have noticed that these fish move throughout the Broads system, particularly at critical times such as spawning and seasonal feeding. They have argued that the waterways should therefore be managed as an interconnected system rather than as separate lakes and have opposed projects aiming to isolate parts of the Broads. However, scientists have often disputed these claims, citing studies on fish behaviour in isolated lakes, unrelated species, or distant regions. Several recently published studies conducted in the Broads have provided strong evidence that this local knowledge of the environment is indeed correct.
In 2017 and 2018, volunteers from the Broads angling community collaborated with scientists to capture 181 Common bream and 44 Northern pike, fitting them with tracking devices to monitor their movements over a three-year period. Using stable isotope analysis, they also examined chemical signatures in fish tissues to determine their diet over time.
The results of the Common bream study were published in May 2021, confirming the movement patterns that anglers had long suspected. The research, led by Dr. Emily Winter and her team, validated the concerns expressed by the angling community and fisheries officers about the importance of habitat connectivity.
Until now, the results of the pike study have not been published. This newly released research sheds light on the movement and behaviour of pike in the Broads, emphasizing the critical role of connected waterways in supporting their natural behaviours and the overall health of the aquatic ecosystem.
The results of studies on the movement, habitat use and feeding behaviour of Northern pike in the Ant, Bure and Thurne have now also been published, shedding more light on fish movement and behaviour in the Broads, and emphasizing the critical role of connected waterways in supporting natural behaviours and the overall health of the aquatic ecosystem. Pike showed high individual variability in movement, with some swimming as little as 18 km over the study period, while others travelled up to 1,182 km. Daily movements ranged from 340m to 3 km, with larger pike moving more than smaller ones, especially in the River Thurne.
All pike increased their movements during the spawning season, but tended to stay in the river system where they were originally tagged, with minimal movement between the Bure, Ant, and Thurne. Nevertheless, these local groups use various interconnected habitats, including main river channels, connected broads and ditches. Most pike detections were in the broads and side waters rather than the main channels. Clearly, ensuring that rivers, lakes, and wetlands remain connected and free from obstacles is vital for the survival and health of pike, allowing them to find food, reproduce successfully, and carry out their natural behaviours, which in turn supports the overall health of the aquatic ecosystem.
With two peer-reviewed and published studies now underscoring the critical importance of interconnected waterways in the Broads, the scientific evidence supporting habitat connectivity is robust and growing. These two main papers are bolstered by additional studies that validate the methods used and reinforce the conclusions drawn, proving the robustness of the research. This work demonstrates that citizen science and local knowledge should be given far more consideration than has been shown in previous projects.
Nature recovery and restoration initiatives should take these results into account and adopt a cautious and holistic approach. The Broads waterways are not a series of isolated lakes but a unified system that thrives on connectivity. Managing them as such is essential to preserve their unique ecological balance and to support the myriad species, including the vital fish populations, that depend on this intricate network.
Duncan Holmes is Vice-Chair of the Broads Society and a Life long Broads Angler.
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