Freshwater tube crab

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Freshwater tube crab
Systematics
Class : Higher crabs (Malacostraca)
Order : Flea crabs (Amphipoda)
Subordination : Corophiidea
Family : Corophiidae
Genre : Chelicorophium
Type : Freshwater tube crab
Scientific name
Chelicorophium curvispinum
( Sars , 1895)

The freshwater tube crayfish ( Chelicorophium curvispinum ) is a species of crayfish that is common in fresh and brackish water. Originally native to the Black Sea and its tributaries, it is now spread over almost all of Europe and is one of the most common neozoa in Central European rivers.

features

Chelicorophium curvispinum reaches a body length of 9 millimeters. It is white or yellowish in color with indistinct dark spots and bands. The dark colored complex eyes are relatively small.

Species of the Corophiidae family can be distinguished from other amphipods by their body shape, which is flattened only slightly laterally but rather dorsoventrally (similar to a woodlouse), the small coxal plates at the base of the legs and, above all, the greatly enlarged second antennae , which are always stronger than all of them Pairs of legs and can be longer than the rest of the body. Chelicorophium curvispinum is one of the few freshwater species of this predominantly marine group. The distinction from other forms living in fresh or brackish water is difficult and only possible under a microscope. From Chelicorophium robustum , with which it often occurs together (e.g. in the Rhine), it differs in the formation of a few small teeth on the last link of the antenna base (pedunculus) (cf.).

Way of life and habitat

Chelicorophium curvispinum reaches three generations per year, it reproduces in Central Europe from April to October. Newly hatched individuals multiply, depending on the season, in the same year or only after hibernation; in this case they die the following summer. A moderate to large excess of females can be observed in natural populations.

The flea shrimp builds living tubes by filtering particles out of the water and sticking them with secretions. He usually does not leave these tubes voluntarily. It feeds as a filter feeder , scraping and scraping material from the surface around its tube. The filter organs are the maxillipedas and the first two pairs of peraeopods (gnathopods), which are covered with long filter bristles and which it pulls through the water in rapid motion (active filter feeder). Hard substrates of all kinds serve him as a base for the living tubes, such as B. stones, wood, water plants. It can also hit the surface of other stuck animals such as B. Cover mussel shells or sponges. It cannot live on soft substrates such as sand or silt, it has no digging ability.

In suitable habitats the flea shrimp can reach enormous densities. It reached up to 18,700 individuals per square meter in the Elbe and even an incredible 75,000 individuals per square meter in the Lower Rhine. At these high densities the flea shrimp can change its habitat massively. Due to the tightly packed tubes and the accumulated fine material, it can coat all stone surfaces with a thick layer of mud and thus displace other hard substrate colonists from the habitat. So he displaced the (also Neozoic) wandering mussel ( Dreissena polymorpha ) from parts of the Rhine. For several years, there is evidence of a population decline, which to predation by also neozoischen later entrained Great killer shrimp is returned

Chelicorophium curvispinum prefers flowing water (rheophil). It occurs less often in stagnant waters, as far as these have hard substrate ground, z. B. on stone packings in the IJsselmeer lakes in the Netherlands. In flowing waters it is almost only found in larger rivers ( Potamal ). In streams, its high temperature requirements are usually not met. In addition, it occurs regularly and in high density in shipping canals. The species mostly colonizes bank areas and does not penetrate far into deep water layers.

It occurs in fresh water, more rarely in brackish water , e.g. B. in the Elbe estuary and the Baltic Sea. But here it is usually replaced by other species of the Corophiidae. When colonizing brackish water, it benefits from its flexible osmoregulation. This is probably due to the fact that the species only entered freshwater relatively recently.

Chelicorophium curvispinum prefers organically moderately to heavily polluted waters. Its saprobic index is 2.2.

Spread and Immigration

The species comes from the area around the Black Sea , it lives in the rivers Don , Dnieper , Dniester and Danube that flow here (up to the Iron Gate ). The first wave of immigration came via the Dnepr , Prypjat , Bug , the Vistula and the Warta. First find in Germany : 1912 in the Müggelsee near Berlin . The further spread took place via northern German canals , from 1987 cancer can be found in the Rhine . A second wave of immigration came over the Danube . The opening of the Main-Danube Canal caused the two populations to mix. The species actively spreads, but is mainly spread by ships, on whose hulls it can build tubes. With ship transport he was z. B. introduced to England (first recorded in 1935 in the Avon ).

The species continues to spread. It did not reach Ireland until 2000.

Systematics

Until the revision of the Corophioidea by Bousfeld and Houwer in 1997, the species was assigned to a broad genus Corophium and accordingly named Corophium curvispinum ; it is mentioned under this name in numerous older articles. The first animals found in Central Europe (1912 in Müggelsee near Berlin) were erroneously described a second time by their discoverer D. Wundsch under the (synonymous) name Corophium devium, afterwards some researchers, especially in England, named the freshwater form Corophium curvispinum var. devium .

A related and very similar species, Chelicorophium sowinskyi , lives in the middle and lower Danube, but (so far?) Not in Central Europe . This is very similar to curvispinum (possibly synonymous according to some editors) and has so far hardly been distinguished.

Individual evidence

  1. ↑ Thomas Ols Eggers & Andreas Martens (2001): Identification key of the freshwater amphipoda (Crustacea) of Germany. Lauerbornia 42: 1-68.
  2. ↑ Ols Eggers & Andreas Martens (2004): Additions and corrections to the identification key of the freshwater amphipod (Crustacea) in Germany. Lauterbornia 50: 1-13.
  3. ↑ Brigitta Eiseler (2010): Identification aids for macrozoobenthos. LANUV worksheet 14. Published by the State Office for Nature, Environment and Consumer Protection North Rhine-Westphalia.
  4. ^ S. Rajagopal, G. van der Velde, BGP Paffen, FWB van den Brink, AB de Vaate (1999): Life history and reproductive biology of the invasive amphipod Corophium curvispinum (Crustacea: Amphipoda) in the Lower Rhine. Archives for Hydrobiology Volume 144 No. 3: 305-325.
  5. ↑ Thomas Ols Eggers: Effects of anthropogenic structures on the macrozoobenthos community of shipping routes - comparison of a free-flowing waterway (Middle Elbe) with a shipping canal (Mittelland Canal) and their significance for neozoa. Diss, Faculty of Life Sciences at the Technical University Carolo-Wilhelmina in Braunschweig. 2006.
  6. ^ FWB van den Brink, G. van der Velde, A. bij de Vaate (1993): Ecological aspects, explosive range extension and impact of a mass invader, Corophium curvispinum Sars, 1895 (Crustacea: Amphipoda), in the Lower Rhine ( The Netherlands). Oecologia Volume 93, Issue 2: 224-232.
  7. ↑ G. van der Velde, S. Rajagopal, B. Kelleher, I. Muskó, A. Bij de Vaate (2000): Ecological impact of crustacean invaders: general considerations and examples from the Rhine River, In: von Pauwel Klein, JC et al. (Editors) (2000): The biodiversity crisis and Crustacea: Proceedings of the 4th International Crustacean Congress, Amsterdam, Netherlands, July 20-24, 1998, volume 2. Crustacean Issues, 12: 3-33.
  8. ↑ Peter Rey, Johannes Ortlepp, Daniel Küry: Invertebrate Neozoa in the Upper Rhine. Spread and ecological importance. Environment series No. 380. Federal Office for the Environment, Forests and Landscape, Bern. 88 p. Download
  9. ↑ Ruurd Noordhuis, John van Schie, Nico Jaarsma (2009): Colonization patterns and impacts of the invasive amphipods Chelicorophium curvispinum and Dikerogammarus villosus in the IJsselmeer area, The Netherlands. Biological Invasions Volume 11, Issue 9: 2067-2084.
  10. ↑ freshwaterecology.info
  11. ↑ Stefan Nehring and Heiko Leuchs: Neozoa (macrozoobenthos) on the German North Sea coast - an overview. (Full text, online, free of charge, PDF, 132 pages, 8.7 MB) Federal Institute for Hydrology , Koblenz 1999, OCLC 174469088 .
  12. ↑ Michael L. Zettler (2000): Biological biodiversity in coastal waters of the Baltic Sea using the example of crayfish (Malacostraca). German Society for Limnology. Conference report 1999 (Rostock): 414-418.
  13. ↑ PM Taylor & RR Harris (21986): Osmoregulation in Corophium curvispinum (Crustacea: Amphipoda), a recent coloniser of freshwater. Journal of Comparative Physiology B: Volume 156, Issue 3: 323-332.
  14. ↑ DIN German Institute for Standardization e. V. (editor) (2004): DIN 38410-1. German standard methods for the examination of water, waste water and sludge - Biological-ecological examination of waters (Group M) - Part 1: Determination of the saprobic index in flowing waters (M 1)
  15. ↑ Frances Lucy, Dan Minchin, JMC Holmes, Monica Sullivan (2004): First Records of the Ponto-Caspian Amphipod Chelicorophium curvispinum (Sars, 1895) in Ireland. The Irish Naturalists' Journal Vol. 27, No. 12: 461-464.
  16. ↑ EL Bousfield & PW Hoover (1997): The amphipod superfamily Corophioidea on the Pacific coast of North America: 5. Family Corophiidae: Corophiinae, new subfamily: systematics and distributional ecology. Amphipacifica 2 (3): 67-139.
  17. ↑ P. Borza (2011): Revision of invasion history, distributional patterns, and new records of Corophiidae (Crustacea: Amphipoda) in Hungary. Acta Zoologica Academiae Scientiarum Hungaricae 57 (1): 75-84.

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