The swan mussel has a thin fragile shell. It is found in fresh stationary waters. It has a foot so that it maneuver a bit. There is one known incident of a swan. Descriptions and articles about the Swan Mussel, scientifically known as Anodonta cygnea in the Encyclopedia of Life. Includes Overview; Brief Summary; Distr. Anodonta-cygnea_jpg. Anodonta cygnea. Provided by Welter Schultes, Francisco Locality: Germany: Schleswig-Holstein, Brammer Teich near Kiel.
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Its native distribution is European-Siberian.
From Wikipedia, the free encyclopedia. Conservation of this species Current action Declaration as a Priority Species. It was formerly common in such places but has been displaced by main drainage schemes in rivers, excess siltation, eutrophication and, recently, by the invasive zebra mussel Dreissena polymorpha.
Species description A very large bivalve shell with a flattened profile and broad, oblong shape.
Swan mussel Conservation status. The shell is thin and pale, whitish or pearly inside due to a thin layer of nacre, but protected by a periostracum outside which gives it a smooth, glossy brown, sometimes green appearance marked with strong concentric growth lines.
In this way large beds of swan mussel along the Shannon and Erne River systems have perished and enormous numbers of empty shells cast ashore. It can reach mm 6 in in size and has a nearly straight dorsal upper or cygneq margin with a drawn out posterior end and slightly rounded to nearly straight ventral anodonya margin. How to see this species Swan mussels can sometimes be seen from fishing stands at the margins of lakes with silty or mud bottoms. The swan mussel is a very large bivalve mollusc which lives in streams, rivers and along lakeshores where the bottom is of rich mud or silt and relatively free of plant growth.
A very large bivalve shell found in silty or muddy backwaters of streams, rivers and lakes. Swan mussel shells appear to be of even thickness throughout, whereas duck mussel shells are clearly uneven and much thicker and opaque towards the lower front end of the shell. In other projects Wikimedia Commons. The story may not end there, however, as the zebra mussel infestation is now waning and there is hope that the swan mussel anodont regain some of the territory lost to its competitor.
Artificial lakes are usually reached when infected fishes are brought in, young mussels are rarely dispersed by water birds.
Anodonta cygnea swan mussel :: Northern Ireland’s Priority Species ::
The shell color is often pale greenish or brownish. Down, BT18 0EU; cedar.
Views Read Edit View history. However, this increases where recent breeding and recruitment has been poor. Unionidae The swan mussel is a very large bivalve mollusc which lives in streams, rivers and along lakeshores where the bottom is of rich mud or silt and relatively free of plant growth.
It differs from Anodonta anatina in being larger shell with straighter, amodonta parallel dorsal and ventral margins; the growth lines of the inner, oldest part of the shell are finer and shallower, and reach the margin. It also has a deeper, less flattened shell with the interior more deeply coated with nacre.
Retrieved 23 April Threatened both in Ireland and Europe by diffuse pollution and the resultant periodic de-oxygenation of waters. Malacologica Bohemoslovaca in Czech. The outlines of shells poking out of the mud can then be seen with the paired pale siphons appearing between the valves. They will then drop off after a period of weeks and find a suitable place on the bottom to begin an independent life.
Zebra mussels are unable to colonise streams where water flow is significant and it is thought that these streams may act as reservoirs of native mussels which will assist in re-colonisation. The swan musselAnodonta cygneais a large species of freshwater musselan aquatic bivalve mollusc in the family Unionidaethe river mussels. Life cycle Adults are long lived and there is nearly always a good proportion of mature shells present in colonies.
This is smaller though still a large shell at mm long but usually with a more distinctly angular shape. Archived from the original on 19 October Because of its morphological variability and its wide range of cygjea, there are over synonyms for this species.
Home Introduction Anodonra Criteria:: Breeding depends upon the presence of reasonable water quality and of fish.
The zebra mussel impacts swan mussels indirectly, by settling on their shells which provide the only hard substrate in many waterways. Click on map to open large map in new window.
The geographical distribution of this species is from the British Isles east to Siberia, and south into northern Africa. Pictures of Anodonta cygnea. Support environmental schemes aimed at reducing diffuse pollution whether from agricultural sources, from inadequate sewage treatment in towns or from the malfunctioning or failure of septic tanks in rural areas.
An annotated list of the land and freshwater Mollusca of Northern Ireland. Diffuse pollution has affected its habitat in most areas and dissolved oxygen is reduced in many to dangerously low xygnea in the summer months.
WoRMS – World Register of Marine Species – Anodonta cygnea (Linnaeus, )
Embryonal shell finely striated along the growth lines, the lines reach the margin. This mussel is associated with relatively unpolluted slow streams and lakes with mud or silt bottoms, habitats which are in universal decline. Index Animalium Sherborn, species and genera until List cynea all species. The Swedish Museum of Natural History. Institute of Zoology, Slovak Academy of Sciences. Lakes, old river arms, artificial lakes, needs silent waters, only rarely in running waters, usually in lowlands.
List of failure reports. Occasionally found in Spain and Portugal in artificially disturbed habitats, where infected fishes from central Europe were released. Glochidia are mature in autumn, are released in spring in England and in Italytheir size 0.
Host fishes for glochidia are Salmo trutta, Perca fluviatilis, Leuciscus leuciscus, Sander lucioperca and Gasterosteus aculeatus, but not Rhodus sericeus.
Archived from the original on 27 December