Ergasilus Sieboldi
| Ergasilus Sieboldi | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ergasilus Sieboldi | ||||||||||||
| Nordmann , 1832 |
The Ergasilus Sieboldi , also known as the gill shrimp , is a parasitic copepod that nests in the gills of fish .
The front part ( cephalothorax ) shows clear blue spots. The females of the genus are around 2 mm long and infest the gill tissue of freshwater fish such as tench , pike , perch , trout and carp , although the last two species are less common. After removing the gill cover , the parasites can be seen with the naked eye.
The parasite infestation is mostly inconspicuous for the fish. Only very heavily infected animals lose weight considerably, which is also known as the back of a knife . Ergasilus Sieboldi is considered to be the carrier of the heteroxenic virus of the lymphocystis, which leads to high mortality rates. It is interesting that studies on the lymphocystis virus showed a direct connection to the seasonal dynamics of the Ergasilus Sieboldi. This gives reason to assume that the copepod serves as a host for the virus and promotes its spread within a population (CUSACK and CONE 1986).
The females anchor themselves with their second pair of antennae in the gill tissue of their hosts and feed on their blood and gill tissue. The males die shortly after mating. From the eggs of the fertilized females, the second generation of parasites develops on the infested fish in the current summer, with the second generation always being more numerous than the first. Ergasilus Sieboldi wanders around on the gills of the host after destroying the gill tissue, looking for a new place to attach and, like the carp lice ( Argulus foliaceus ), goes through numerous developmental stages, of which only the last stage is the female Gill crabs live parasitically on the gills of fish.
Depending on the severity of the infestation, up to 14,000 gill shrimp can be counted in a fish of two generations each. Ergasilus Sieboldi is a serious parasite because its parasitic way of life makes it susceptible to secondary infections, e.g. B. molds such as Ichthyosporidium hoferi , Saprolegnia or bacterial infections by Aeromonas hydrophila , is responsible in its host.
literature
- Alexander von Nordmann: Micrographical contributions to the natural history of invertebrates . G. Reimer, Berlin 1832