Telmatogeton japonicus

Telmatogeton japonicus Tokunaga, 1933 – a marine splash midge

Synonyms: Telmatogeton remanei Remmert, 1963Common names Splash midge (UK, CAN, USA)


It is not really possible to identify chironomid larvae to species, so only when adults (imagines) are present can they be accurately identified to species. The other species of the genus seem to be primarily from the southern hemisphere (Womersley 1936; Newman, 1988), but T. remanei was described from the Baltic and T. murrayi from Iceland (Sæther, 2009).


Native distribution: Japan. It has also been found in Hawaii, and this is included in the native area by some authors.

Introduced distribution: Presently this species is very widespread, occurring in northern Europe, North America and the Pacific. In Europe the first record, as T. remanei, is from 1962 in the estuary near Kiel (Remmert, 1963). In the following years it was found at a number of ports in the Baltic, e.g. Rostock (1982), Rügen (1984), Gdynia (1977), and also in the Gullmarsfjord on the Swedish west coast (1983) and Helgoland in the North Sea (1982). At this point it was synonymized with the Japanese T. japonicus (Kronberg, 1986). In Poland it had been described as a new species, T. gedanensis Szadziewski, 1977. In 2003 it was found on Danish windfarms in the North Sea (DONG Energy, 2006) and in 2005 it was found on buoys in Belgium (Kerckhof et al., 2007). In 2007 it was found on the Swedish Baltic Sea coast (Brodin & Anderson, 2009) and in 2008 on the coast of Finland (Raunio et al., 2009). There are also records from Britain, Madeira, Azores and Iceland (Brodin & Anderson, 2009), but the latter may be a separate species (Sæther, 2009).

In 1949 it was found in Florida and New York on the east coast of the USA (Wirth, 1952). It was first recorded from Canada between 1990 and 1994 (Colbo, 1996).

It may also occur in Australia (Newman, 1988)


The following information pertains only to the larvae. In its native area there are two annual population maxima (Sunose & Fujisawa, 1982). It feeds on seaweeds, mostly green algae but also cyanobacteria . It builds tubes that protect the larvae against exposure, and it is not able to swim (Kronberg, 1988). It seems to prefer concrete as a substrate even in its native area (Sunose & Fujisawa, 1982; Kronberg, 1988; Brodin & Andersson, 2009).

Reproduction: Only the larvae and pupae occur in the supratidal zone. The adults live for only a few days (Sunose & Fujisawa, 1982). Females produce 200-300 eggs, which are deposited individually. Larvae go through 4 instars before pupation (Kronberg, 1988).


Its dense tube may modify microhabitats, but no serious impacts are known.