Gianius aquaedulcis
Common Name:
A tubificid worm
Synonyms and Other Names:
formerly Phallodrilus aquaedulcis (Hrabe 1960)
Identification:
Externally, Gianius can be distinguished by a rounded prostomium, as long as it is broad at the peristomium, bifid setae with upper teeth thinner and shorter than lower, 3–4 setae per bundle toward the anterior, and 2 per bundle toward the posterior. Internally, G. aquaedulcis has short and narrow spermathecal ducts (Brinkhurst 1971).
Size:
4 mm
Native Range:
Western Europe in Germany's River Weser and inland caves in Spain and France (Farara and Erseus 1991).
|
|
|
This map only depicts Great Lakes introductions.
|
|
Great Lakes Nonindigenous Occurrences:
This species is established in the Niagara River in Erie and Niagara Counties, New York (Mills 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 Gianius aquaedulcis are found here.
Table last updated 5/1/2024
† Populations may not be currently present.
Ecology:
The highest densities of Gianius aquaedulcis in the Niagara River were found at depths ranging from 1.8 m to 17.3 m, the vast majority residing in 3–6 m of water, and at stations with flow rates greater than 0.2 m/s at the sediment surface (Farara and Erseus 1991).
Means of Introduction:
Noted as being dispersed into the Great Lakes region by ballast water from international shipping in 1983 (Spencer and Hudson 2003).
Status:
Gianius aquaedulcis is established throughout most of the course of the Niagara River, but no specimens have been found in the Great Lakes proper or elsewhere in North America (Farara and Erseus 1991).
Great Lakes Impacts:
Current research on the environmental impact of Gianius aquaedulcis in the Great Lakes is inadequate to support proper assessment.
Realized:
Farara and Erseus (1991) found G. aquaedulcis to be the most dominant taxa at many stations along the Niagara River, but its impact on native ecosystems is unknown.
There is little or no evidence to support that Gianius aquaedulcis has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Gianius aquaedulcis 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
Little research has been pursued concerning control of Gianius aquaedulcis, likely because of its limited known range to the Niagara River in North America (Spencer and Hudson 2003).
Biological
While no there are no known biological controls specifically for Gianius aquaedulcis, 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 nonindigenous to the Great Lakes region and across nearly all of the United States (Fuller et al. 2013).
Research on benthic macroinvertebrate communities in southwestern Lake Ontario before and after the invasion of Dreissena polymorpha (zebra mussels) and Dreissena bugensis (quagga mussels) suggests that the presence of Dreissena helps to improve benthic habitat, facilitating increases in macroinvertebrates, including the tubificids Potamothrix vejdovskyi and Spirosperma ferox (Stewart and Haynes 1994). This indicates that control of invasive quagga and zebra mussels could facilitate improved control of benthic macroinvertebrates such as the tubificids.
Physical
There are no known physical control methods for this species.
Chemical
While there are no known chemical controls specifically for Gianius aquaedulcis, 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.
Remarks:
During a baseline study of benthic invertebrates of the Niagara River in 1983, a substantial number of G. aquaedulcis were found and identified under the old taxonomy, Phallodrilus aquaedulcis (Hrabe, 1960), a new record in North America (Farara and Erseus 1991). Later, Erseus (1992) revised the Phallodrilinae, splitting the genus into 20 different genera, and Phallodrilus aquaedulcis became Gianius aquaedulcis.
References
(click for full reference list)
Author:
Jacobs, G., J. Larson, A. Fusaro, and T, Makled
Contributing Agencies:
Revision Date:
9/12/2019
Citation for this information:
Jacobs, G., J. Larson, A. Fusaro, and T, Makled, 2024, Gianius aquaedulcis: 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=2542&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 9/12/2019, Access Date: 5/1/2024
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.