How can fish thrive in rivers that are used as water resources? Scientists at Southampton have set out to understand fish behaviour and swimming abilities to discover how and why they migrate up and downstream. This knowledge is key to the design of the next generation of dams and barrages as engineers can now use innovative techniques to cause less damage to fish stocks. Although some work has been carried out on ways to protect commercially important fish such as salmon, through introducing fish ladders, many other species suffer.For example since the 1980s, eel populations have collapsed by around 95 per cent as conventional mitigation techniques fail to protect this weaker-swimming elongated species.
More than 60 per cent of the world’s largest rivers including the powerful Amazon and Yangtze waterways have been controlled with dams and barrages that influence the seasonal flow of water and increasingly generate power. These structures disturb the natural flow of rivers water. In addition, they cause major problems to fisheries and other freshwater ecosystems worth around US$70billion a year because fish are killed in turbines or damaged by structures. It is essential to understand what is happening beneath the surface of the water to develop ways of protecting fish. Policy-makers are also interested in how the re-introduction of beavers, natural dam-builders, could influence the courses of rivers or whether their activities could damage fish stocks.
Worldwide research on fish behaviour is being carried out by Professor Paul Kemp and colleagues. They have worked in the UK and Sweden to develop guidelines for the effective use of screens to protect eels from damage, which have been incorporated into UK Environment Agency recommendations. Other projects have involved Chinese carp in the Yangtze in China, Pacific lamprey in Washington State, USA and fish on the River Warnow in northern Germany. The Southampton team has won funding from organisations including the European Union, Environment Agency and Leverhulme Trust to investigate and advise policymakers. The University of Southampton’s experimental flumes have proved invaluable in carrying out practical assessments of fish behaviour. Most of the research so far has centred on the use of screens to keep fish out of intake systems and turbines but attention is also turning to the use of lights and acoustics to encourage them to keep away. In related work, a project commissioned by the Scottish Government has analysed the effect of the possible re-introduction of beavers in rivers in Scotland. It concluded, on balance, that the ecological impact of their dam-building would not damage the lucrative salmon fishing industry.
Fish can live in harmony with the commercial organisations, that use their water, if enough attention is paid to their requirements. Protecting fish from damage or death in inlet pipes and turbine blades is challenging. However, extensive research in rivers and waterways across the globe by Professor Paul Kemp has come up with viable answers. Researchers have examined traditional and technological answers to preserving fisheries and their advice has been taken up by decision makers. This work continues to discover new ways of protecting fish.