Threats to rivers
Human activities can influence rivers in a variety of ways. Intensification of modern agriculture and water abstraction for irrigation can reduce river flows and increase amounts of fine sediment and agricultural pollutants within rivers. Dams, weirs and other permanent man-made barriers reduce river connectivity, meaning availability of suitable habitat for fauna, including migratory fish species, may be limited. Against this backdrop of concern, growing populations and so, demands for food and agriculture, and climate change due to greenhouse gas emissions, further increase the pressures placed on our rivers.
The Environment Agency, the environmental regulatory authority of England, are involved in the management and regulation of rivers and their catchments. Meanwhile, the many Trusts and collaborating partners around the UK are working closely with local farmers to limit agricultural pollution in rivers. We at the RACG firmly believe we can all play a role in helping to improve river habitats and actively support relevant stakeholders in their work to improve riverine habitats for the benefit of native fauna and flora. The following sections discuss the importance of some key fish habitats and explains how we at the RACG are/ will be involved in the management of these important habitats, for the benefit of river fisheries.
Importance of Nursery Habitat
Suitable nursery habitat is of critical importance for the early development of riverine fish. Upon hatching, fish will often drift downstream in the flow in search of low energy, often shallow sections of water. These low energy areas keep newly hatched fish away from predators and strong flows, and provide the juvenile fish with the food they need to develop. In the initial stages of life, these tiny fish are looking to grow large and strong, quickly. If fish do not develop at a suitable rate due to for example, a lack of food, they may become susceptible to predation or displacement during high flows. The RACG aims to collaborate with local clubs throughout river catchments, to improve awareness of the nursery habitat suitability and its importance. We also aim to provide support and knowledge in the development of both nursery and residence areas for fish.
Importance of Residence Habitat
Fish, regardless of size, need cover to escape from predators and feel safe. Woody debris or man-made structures can be introduced to rivers to improve the quantity and quality of residence habitat and manipulate natural processes, by for example, purging fine sediments from degraded spawning gravels. The RACG aims to work with key stakeholders on a range of habitat restoration projects to improve the quality of residence areas in rivers.
Importance of Spawning Habitat
Different fish spawn in different ways – some like Salmon, trout and Barbel lay their eggs in the substrate whereas species like carp, tench and roach deposit their eggs in/ on vegetation. Regardless of the spawning mechanism, spawning habitat availability and suitability are important determinants of natural recruitment in rivers. The RACG aims to help angling clubs and societies to restore or improve spawning habitats for the benefit of fish populations. Furthermore, by collaborating with key stakeholders, we aim to gain better understanding of the factors influencing river fish recruitment and how these can be managed.