Asiatic beach crab
| Asiatic beach crab | ||||||||||||
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Asiatic beach crab ashore |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Hemigrapsus sanguineus | ||||||||||||
| ( De Haan , 1853) |
The Asian beach crab ( Hemigrapsus sanguineus ) is a species of crab that originally comes from the temperate to subtropical coastal waters of the northwestern Pacific (China, Japan, Korea).
description
The animals are colored green to brown, but there are also other color variants, including light cream-colored variants. The legs are usually banded. The carapace becomes up to 3.2 cm wide, with legs a total size of 7 cm is rarely exceeded. The animals show a clear sexual dimorphism : Males have conspicuous fleshy structures on the claws that the females lack. In addition, they form on average more powerful pliers.
Way of life
The animals live in waters close to the coast with a depth of approx. 2–5 m; specimens have been sighted at a depth of 20 m, but this should not be the preferred water depth. Asian beach crabs are aggressive, predatory omnivores: everything that is smaller or the same size is attempted to be overwhelmed, and cannibalism has also been proven.
The mating season is unspecific in terms of tides or seasons. Females can produce up to 50,000 eggs four times a year. In comparison, crabs from the North and Baltic Seas have a maximum of two generation times per year.
distribution
Originally from the Northwest Pacific, the crabs were accidentally brought to the French Atlantic coast in the 1990s and have been spreading unhindered ever since. The first find from Germany (Norderney, Lower Saxony) dates back to 2006. Since then, the crab has spread more and more. In 2012 it was firmly established in front of the Borkum bathing beach. Sightings from the Atlantic coast are also reported from the USA.
