River Medway Nursery Area
Young fish often require different food and conditions to adults. Nursery areas are places with suitable food and environmental conditions for these juvenile fish, and also provide shelter to protect them from predation.
Many commercial fish species spend their early years in inshore areas, migrating into offshore waters when they reach adulthood and only returning inshore again to spawn. This helps to identify a distinct separation between juvenile and adult habitats and therefore a defined nursery area.
By protecting juvenile fish in these distinct nursery areas, it in turn enhances the offshore harvestable stocks of fish. By ensuring these young fish have the best possible chance of survival, they are able to reach adulthood, reproduce and contribute to the future population.
How does Medway Nursery Area help juvenile fish?
Although saltmarshes may look inconspicuous they perform a number of key biological, chemical and ecosystem functions as well as aid coastal protection. Saltmarshes can help maintain water quality by filtering the water before it ebbs to the sea, having important nitrogen, carbon and pollution storage functions.
Saltmarsh habitats support distinctive plant communities, and are important feeding, breeding and roosting grounds for birds. The value of saltmarsh habitats is now recognised internationally and nationally, with EU legislation to ensure that saltmarshes are protected and restored.
Unfortunately, key functions of saltmarsh ecosystems are now being compromised. It is estimated that two per cent of English saltmarshes are lost to the sea every year as a consequence of sea level rise. In addition to this, human encroachment into estuarine, intertidal and saltmarsh areas has created the phenomenon of coastal squeeze, where the seaward habitat is diminished through sea level rise, whilst sea defence structures, such as sea walls, are limiting compensatory inland encroachment.
The saltmarsh habitat is specifically important to juvenile fish. The complex habitat, with muddy channels and saltmarsh plants, provides areas for young fish to hide from predators. The cloudy, muddy water is also good for juvenile fish, as it offers more protection from visual predators. Fish populations tend to move onto the high intertidal and saltmarsh areas on flood tides and then return to deeper water on the ebb.
The Medway has been surveyed over a number of years by the Environment Agency, who have found lots of juvenile fish using the area. By protecting the large areas of intertidal saltmarsh and mudflat in the Medway, we are protecting the young fish that are known to use this area.