Common cockle
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The edible or common cockle ( Cerastoderma edule ) |
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| Cerastoderma edule | ||||||||||||
| ( Linnaeus , 1758) |
The common cockle , or also edible cockle ( Cerastoderma edule ), is a type of mussel from the order of the Cardiida . The common cockle is the most common mussel found in the North Sea.
features
The shell of the common cockle is usually elongated-elliptical and about five centimeters long. However, the shape is variable. The case is relatively strongly arched and thick-shelled. The surface is decorated with 20 to 28 mm wide, rounded ribs that are crossed by finer concentric growth lines. Fine scales are formed at the crossing points. The color varies from white to yellow-brown to brown. The lock has two cardinal teeth in the right flap and two anterior and two posterior posterior teeth. In the left valve there are two cardinal teeth and an anterior and posterior posterior tooth. The ligament is on the outside. The anterior and posterior sphincter muscles are approximately the same size (isomyar). The siphons are relatively short. The surface line is entire (integripalliat).
Way of life and occurrence
The common cockle prefers sandy-silty soils at a depth of 0 to about 10 m. In the tidal areas (tidal flats) of the North Sea, it is the most common type of mussel; The highest population density is reached in about 3 m water depth with up to 245 adult individuals per square meter. It lives buried close to the sediment surface no deeper than 5 cm, its short siphons just reach the sediment surface. If it is flushed free, it can dig itself back in with its foot relatively quickly (in about 2 to 10 minutes). It often moves a little further on the surface before digging in again. It tolerates relatively low levels of oxygen and can even survive for several days in an oxygen-free environment. It is relatively tolerant of fluctuations in salinity, but requires around 10 ‰ of salt. Eggs and sperm are released into the open water at the end of May, where fertilization occurs. A female produces between 5000 and 50,000 eggs per breeding period. The larvae live in free water for another 2 to 3 weeks before they move on to soil life. The animals normally live to be around 3 years old, under particularly favorable conditions up to 9 years.
distribution
The species occurs in the eastern North Atlantic from the Barents Sea in the north to Mauritania in the south. It is one of the most common mussels in the North Sea and is also found in the western Baltic Sea . However, it seems to be absent in the Mediterranean .
Commercial importance
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As the name of the edible cockle implies, the mussel is caught commercially. Around 2500 million specimens were fished in the Netherlands alone in 1993.
Similar species
The shell of the common cockle is very similar to the related species Cerastoderma lamarcki .
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Individual evidence
literature
- Rainer Willmann: Mussels of the North and Baltic Seas. Neumann-Neudamm, Melsungen 1989, ISBN 3-7888-0555-2
- Guido Poppe and Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3-925919-10-4
Web links
- The cockle. Wadden Sea Protection Station, accessed on September 11, 2012 .