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Local, National and International Importance of the Mersey estuary
Estuaries are extremely productive ecosystems containing huge amounts of energy locked up in huge numbers of invertebrates. Estuarine wildlife especially waders and duck, depend on invertebrates in the mud and silt and the large amounts of seeds produced by salt marsh plants to sustain them through the winter period.
The Mersey Estuary is no exception, since water quality has improved, the estuary has become a haven for large numbers of waders and wildfowl offering these birds areas of undisturbed marsh and tidal mudflats which make it an attractive place to spend the winter, or as a staging post on the way to, or from, southern Europe and Africa.
The Mersey estuary has also become very important, at National and International level, for the survival of many wader and duck species, a fact which has been recognized and designated in several ways. In 1981, much of the estuary was given the status of Site of Special Scientific Interest to help safeguard its habitats and wildlife. Non-statutory nature reserves have also been established at many sites along its length. Another major step was the designation in 1995 of much of the estuary as a Ramsar site and Special Protection Area (SPA) under the EC Wildbirds Directive 1979. In accordance with the Convention on Conservation of Wetlands held in Ramsar, Iran, a wetland is considered to be of international importance if it regularly supports at least 1% or more of the numbers in a geographical population of a species. The Dee, Alt and Ribble estuary have been Ramsar sites for some time, the Mersey estuary fulfilled the requirements many years before its designation.
The number of birds using the estuary vary but, in the period 1996 to 2001, no less than seven species of wildfowl reached ‘Ramsar level’ - Dunlin, turnstone, teal, black-tailed godwit, redshank, pintail, shelduck. (This duck comes to the Mersey in large numbers in the summer, to moult.) The estuary is also nationally important (supporting at least 1% of the British population) for wigeon, lapwing, curlew, golden and grey plover. Gulls and terns also use the estuary with terns mostly feeding in the Outer estuary.
The range of fish species reaching the Inner and Upper estuary has increased to over 50. Sea bass, flounder and shoals of sprat are now common, and recent catches have included sole, dogfish, rays, mackerel as well as conger. Salmon are probably breeding in the Mersey river system since juveniles were found in the river Goyt. Commercial interest in the river has also increased, lobster fishing and fishing for mussels and shrimp and sea fishing trips out of Merseyside are becoming a regular feature. Angling from local areas along the Mersey has also become a regular feature.
As fish numbers increased in the Mersey, so to have sightings of Cetaceans (porpoises, dolphins and whales) . A stroll along one of the promenades along the estuary or a trip on the Mersey Ferry may be rewarded by the sight of fins cutting the water’s surface belonging, most likely, to a harbour porpoise or bottle-nosed dolphin. Seals too, are regularly seen in the Estuary and upriver as far as Warrington where they have been known to remain for some time. The most unusual and rarest of these being the Hooded Seal, a Greenland species, which hauled itself on the mud banks at Spike Island in 1997.
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THE MERSEY ESTUARY - NATURALLY OURS |
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Invertebrates, Fish, Mammals |
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Invertebrates are interesting and important in their own right, but also as part of the food chain. Since water quality has improved, the Mersey supports a typical estuarine fauna. Invertebrates include such species as pink and green ragworm, white catworm, lugworm in sandy foreshores, shore crabs, small Hydrobia snails and shrimps (as well as sand gobies) in small pools, mussels, prawns, sea anemone in rock pools along Egremont shore, Korean sea squirts and common jellyfish in some of the docks whilst damselfly, dragonfly and caddisflies are found further up river. |