Ripistes parasita
Common Name:
An oligochaete
Synonyms and Other Names:
Ripistes parasitica, Ripistes macrochaeta
Identification:
Dorsal setal bundles on segments VI–VIII are characterized by 2–16 giant hair setae; following segments have 1–3 moderately long hairs. Ventral setae are absent on segments IV and V. Stomachal dilation is sudden, beginning in segments VI or VII. Clitellum is located in ½ V–½ VIII; spermathecal ampulla are large and baglike with a fairly long, well-defined duct. Penial setae 2 per bundle with a simple hook. Swims with sagittal movements; constructs fixed, hyaline tubes (Brinkhurst 1971, Brinkhurst and Jamieson 1971). Note: segments are counted from anterior to posterior using roman numerals.
Size:
8 mm
Native Range:
Ripistes parasita is native to Europe and Lake Baikal in Asia (Brinkhurst and Jamieson 1971).
Great Lakes Nonindigenous Occurrences:
This species has been found in Lake Huron, Lake Superior, and the St. Mary's River in Michigan (Winnell and Jude 1987; Grigorovich et al. 2003; Spencer and Hudson 2003); in Lake Superior at Duluth Harbor in Minnesota (Grigorovich et al. 2003); in the Chemung, Cohocton, Chenango, and Hudson rivers in New York (Mills et al. 1993); and in Lake Michigan, Lake Superior, Lake Huron, Thunder Bay, Chemung River, Chenango River near Binghamton, and Cohocton River near Campell, NY (Spencer and Hudson 2003; Mills et al. 1993).
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Ripistes parasita are found here.
Full list of USGS occurrences
Table last updated 12/14/2025
† Populations may not be currently present.
* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).
Ecology:
This aquatic oligochaete has been found in waters between 6 m and 10 m deep in the Great Lakes, both on bare, rocky substrates and amongst macrophyte vegetation (Barton and Griffiths 1984; Winnell and Jude 1987; Grigorovich et al. 2003). Specimens taken from riverine habitats occupied waters between 0.9 m and 3.5 m deep and in flow rates ranging from 0 to 50 cm/s (Simpson and Abele 1984; Montz 1988).
Great Lakes Means of Introduction:
The prevalence of Ripistes parasita at sites near major shipping ports suggests invasion via international shipping (Winnel and Jude 1987; Grogorovich et al. 2003). Ballast water is attributed to the dispersal of this species, and evidence suggests that R. parasita can attach to boat hulls, which may facilitate its spread into new water bodies (Rothlisberger et al. 2010; Dinkins et al. 2017).
Great Lakes Status:
Reproducing and overwintering where collected. Most recent collections include Lake Superior and areas of Minnesota and Wisconsin in 2019 (USFWS 2020). Additionally, Montz (1988) stated that the sporadic distribution of R. parasita could be the result of typical benthic sampling methods leading to either the loss or destruction of this organism, and that this naidid may be much more widespread than records show.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
GLANSIS is currently adding new, standardized Great Lakes-specific impact assessments to species fact sheets. During this period, there may be some redundancy with the "Impact of Introduction" section above. Once all species' Great Lakes impacts have been entered here, this information will replace the original Impact section, which will then appear only on the USGS NAS site. Current research on the environmental impact of Ripistes parasita in the Great Lakes is inadequate to support proper assessment.
The establishment of Ripistes parasita in the Great Lakes region is thought to be its first successful movement outside of its native Eurasian distribution (Mills et al. 1993); consequently, the impact of this species is difficult to predict or gauge based on invasion history. Present sporadically throughout the Great Lakes but most recently reported in Lake Superior in 2019 (USFWS 2022), R. parasita can tolerate a broad range of water quality, including those impacted by anthropogenic influences (Krodkiewska and Spyra 2015; Dinkins et al. 2017). This species can inhabit waters that may be inhospitable to its competitors. It is possible that due to inaccurate sampling methods, the abundance of naidids and the potential of R. parasita to interact and affect communities has been underestimated (Montz 1988).
There is little or no evidence to support that Ripistes parasita has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Ripistes parasita has significant beneficial effects in the Great Lakes.
Management:
Regulations
There are no known regulations for this species.
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
While no there are no known biological controls specifically for Ripistes parasita, Brown trout, Salmo trutta L., has been shown to prey on oligochaetes, and its removal from an experimental environment led to rapid multiplication of benthic fauna (Wahab et al. 1989). However, brown trout is itself an invasive species in the Great Lakes region and across nearly all of the United States (Fuller et al. 2013).
Physical
There are no known physical control methods for this species.
Chemical
Ripistes parasita has been found to occur in greater numbers where water quality is impaired by industrial pollution, therefore greater measures to control pollutants such as heavy metals and particulate matter might help control this oligochaete (Simpson and Abele 1984). Furthermore, declines in Oligochaeta in southern Lake Michigan were recorded between 1980 and 1993 in correlation with reductions in phosphorus loads (Nalepa et al. 1998), suggesting that reduction of excess nutrients would help to reduce oligochaete populations.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
References
(click for full reference list)
Author:
Jacobs, G., J. Larson, A. Fusaro, T. Makled, and C. Shelly
Contributing Agencies:
Revision Date:
7/15/2025
Citation for this information:
Jacobs, G., J. Larson, A. Fusaro, T. Makled, and C. Shelly, 2025, Ripistes parasita: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/GreatLakes/FactSheet.aspx?Species_ID=2244, Revision Date: 7/15/2025, Access Date: 12/15/2025
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.