Neascus brevicaudatus
von Nordmann, 1832
Common Name:
A digenean fluke, trematode
Synonyms and Other Names:
Holostomum brevicaudatum, Diplostomum brevicaudatum, and Tetracotyle brevicaudata
Identification:
This is a fluke that attaches to the eyes of its host fish. It does not form cysts. It has two main body regions; the anterior region of the body is shaped like a heart and narrows towards the posterior end. There is a relatively small acetabulum (ventral sucker) in comparison with the oral sucker. The mouth is also relatively small, whereas the oesophageal bulb is wide at the front and narrows toward the back (Dujardin 1845; Hughes 1928). Neascus brevicaudatus may not be the only member of this genus present in the Great Lakes - not all reports identified to genus level can be presumed to be N. brevicaudatus.
Size:
0.75 mm in length (Dujardin 1845)
Native Range:
This is a native Eurasian fluke, typically found in eastern Europe, upper Asia, Siberia, and the Ponto-Caspian region (including the Caspian, Black, and Aral Seas) (Shulman 1961; U. S. Department of the Interior 1993).
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This map only depicts Great Lakes introductions.
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Great Lakes Nonindigenous Occurrences:
The first Great Lakes collection of N. brevicaudatus was on Eurasian Ruffe (Gymnocephalus cernua) from Pokegama Bay, Wisconsin, within the St. Louis River tributary of Lake Superior (Pronin et al. 1998, U.S. Department of the Interior 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 Neascus brevicaudatus are found here.
Table last updated 5/1/2024
† Populations may not be currently present.
Ecology:
N. brevicaudatus occurred on eyes of ruffe from which it was collected in the St. Louis River (U. S. Department of the Interior 1993). It is considered a rare species and was originally reported from eyes of Perca fluviatilis (von Nordmann 1832; von Nordmann 1843) and Lota vulgaris (Zandt 1924) in Eurasia. Neascus spp. have been found in more than 44 different species of fish in Lake Erie, unfortunately most parasites were not identified to species. This species matures in piscivorous birds.
Means of Introduction:
N. brevicaudatus probably arrived in North America with Eurasian ruffe in ballast water (U. S. Department of the Interior 1993).
Status:
Established.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
There is little or no evidence to support that Neascus brevicaudatus has significant environmental impacts in the Great Lakes.
Neascus spp. are documented to cause pathologies and mortality of fish in some cases, especially young fish (Muzzall and Whelan 2011). The only occurrence of N. brevicaudatus in the Great Lakes has been from the introduced Eurasian Ruffe (G. cernua) at 5% prevalence with very light (<1 parasite/host) infections (Pronin et al. 1998). Due to the slow rate of population growth and expansion of N. brevicaudatus, its impacts in the Great Lakes are believed to be negligible (Pronin et al. 1998). Larvae of this species mature in piscivorous birds (Muzzall and Whelan 2011); however, the effects of such infections have not been studied.
There is little or no evidence to support that Neascus brevicaudatus has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Neascus brevicaudatus has significant beneficial effects in the Great Lakes.
Realized:
Neascus brevicaudatus is believed to be unlikely to help regulate populations of the introduced Eurasian Ruffe (U.S. Department of the Interior 1993).
Management:
Regulations (pertaining to the Great Lakes)
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
There are no known biological control methods for this species.
Physical
There are no known physical control methods for this species.
Chemical
There are no known chemical control methods for this species.
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:
Kipp, R.M., A.K.Bogdanoff, A. Fusaro and R. Sturtevant
Contributing Agencies:
Revision Date:
9/13/2019
Citation for this information:
Kipp, R.M., A.K.Bogdanoff, A. Fusaro and R. Sturtevant, 2024, Neascus brevicaudatus von Nordmann, 1832: 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=2361&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 9/13/2019, Access Date: 5/2/2024
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.