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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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.
Diffuse pollution has affected its habitat in most areas and dissolved oxygen is reduced cygneaa many to dangerously low levels in the summer months. Similar species The only other large mussel found in still or nearly still waters is the duck mussel Anodonta anatine.
The zebra mussel impacts swan mussels indirectly, by settling on their shells which provide the only hard substrate in many waterways. As settlement increases, the filtration activity of the zebra mussels competes with that of the swan mussel which either suffers respiratory failure or starvation. It differs from Anodonta anatina in being larger shell with straighter, more parallel dorsal and ventral margins; the growth lines of the inner, oldest part of the shell are finer and shallower, and 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. 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.
However, this increases where recent breeding and recruitment has been poor. This is smaller though still a large shell at mm long but usually with a more distinctly angular shape.
Retrieved 23 April Its native distribution is European-Siberian. In other projects Wikimedia Commons.
Glochidia are mature in autumn, are released in spring in England and in Italytheir size 0. It can reach mm 6 in in size and has a nearly straight dorsal upper or hinge margin with a drawn out posterior end and slightly rounded to nearly straight ventral lower margin. Malacologica Bohemoslovaca in Czech. This page was last edited on 4 Octoberat In Switzerland in up to m altitude.
Retrieved from ” https: Archived from the original on 14 February The geographical distribution of this species is from the British Isles east to Siberia, and south into northern Africa. Swan mussel Conservation status.
Swan mussel – Wikipedia
Down, BT18 0EU; cedar. The dorsal upper margin usually lies at an acute angle to the line of the ventral lower margin giving the shell a distinct wedge shape, instead of being almost parallel as in the swan mussel which produces a more oblong shape.
The outlines of shells poking out of the mud can then be seen with the paired pale cygne appearing between the valves.
Host fishes for glochidia are Salmo trutta, Perca fluviatilis, Leuciscus leuciscus, Sander lucioperca and Gasterosteus aculeatus, but not Rhodus sericeus. Lakes, old river arms, artificial lakes, needs silent waters, only rarely in running waters, usually in lowlands. Click on map to open large map in new window.
Artificial lakes are usually reached when infected fishes are brought in, young mussels are rarely dispersed by water birds.
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How to see this species Swan mussels can sometimes be seen from fishing stands at the margins of lakes with silty or mud bottoms. Nomenclator Zoologicus Neave updated, genera.
Wikimedia Commons has media related to Anodonta cygnea. Tolerates eutrophic conditions, but not in the last toxic stadium. Retrieved 4 January Because anodpnta its morphological variability and its wide range of distribution, there are over synonyms for this anodlnta.
Institute of Zoology, Slovak Academy of Sciences. The parasitic larvae are called glochidia and are produced in spring and carried by the current until they contact a bottom-living fish. Occasionally found in Spain and Portugal in artificially disturbed habitats, where infected fishes from central Europe were released.
Shell yellowish or greenish brown, thin, not very solid, ligament long and narrow, without teeth, lower side of frontal interior margin not thickened.