Heteropsyllus nr. nunni
Coull, 1975
Common Name:
A copepod
Synonyms and Other Names:
Identification:
Heteropsyllus nr. nunni similar to H. nunni, but differs in overall body shape and the specific morphology of the 5th leg (Garza and Whitman 2004).
Heteropsyllus nunni can be distinguished from other Heteropsyllus spp. by the 1st endopod segment on leg 1, which is shorter than the whole exopod, and the relatively large rostrum (extended portion of the head). The caudal rami (two branches on the tail) exhibit short terminal setae and stout outer setae. There is an oval-shaped plate on the dorsal surface in the cephalothoracic region that may be where cyst formation takes place (Coull and Palmer 1980; Coull and Grant 1981; Lesko et al. 2003).
Size:
~510 µm long (Horvath et al. 2001)
Native Range:
Unknown, given that H. nr. nunni may be a separate species from H. nunni. Heteropsyllus nunni is native to the Atlantic coast of North America, while most other Heteropsyllus spp. are native to coastal marine areas of northern Europe (Horvath et al. 2001).
Great Lakes Nonindigenous Occurrences:
This species was recorded for the first time in 1996 from Lake Michigan. A few individuals have also been recorded from Lake St. Clair (Horvath et al. 2001) and northwestern Lake Huron.
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 Heteropsyllus nr. nunni are found here.
Full list of USGS occurrences
Table last updated 4/23/2024
† Populations may not be currently present.
Ecology:
Heteropsyllus nunni generally occurs at high densities in winter. Nauplii (newly hatched individuals) mature in spring, become adults by early summer, and encyst for 3–4 months during the summer. Females and males mate after encystment occurs and females produce eggs one week after mating (Williams-Howze 1996). Heteropsyllus nunni is the only known marine harpacticoid copepod that has a diapause stage within a cyst (Coull and Grant 1981; Williams-Howze and Coull 1992; Williams-Howze 1996; Williams and Biesiot 2004).
Heteropsyllus nr. nunni from Lake Michigan does not, however, appear to exhibit the winter univoltine (one generation per year) reproductive strategy of H. nunni. Adults in Lake Michigan occur at high densities in both July and December (Horvath et al. 2001). Heteropsyllus nr. nunni occurs from 1–15 m depth in Lake Michigan and densities are highest at 9 m. It is a nearshore benthic species found on sand substrate (Horvath et al. 2001). Similarly, H. nunni on the Atlantic coast of North America can occur in very shallow water sand flats (Williams-Howze and Coull 1992).
Means of Introduction:
Probably introduced in ballast water, like most other copepod species introduced to the Great Lakes (Horvath et al. 2001).
Status:
Established in Lake Michigan and northwestern Lake Huron. Its status in Lake St. Clair is uncertain at present.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
Current research on the environmental impact of Heteropsyllus nr. nunni in the Great Lakes is inadequate to support proper assessment. Realized:
Heteropsyllus nr. nunni has dominated the harpacticoid community in shallow sites (up to 9 m) in Lake Michigan. This may either be due to successful competition with native species for similar resources or the ability to exploit unused resources (Garza and Whitman 2004, Horvath et al. 2001).
There is little or no evidence to support that Heteropsyllus nr. nunni has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Heteropsyllus nr. nunni has significant beneficial effects in the Great Lakes.
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
The Great Lakes and Mississippi River Interbasin Study (GLMRIS 2012) suggests that alteration of water quality using carbon dioxide, ozone, nitrogen, and/or sodium thiosulfate could be effective in preventing upstream and downstream movement of copepods. It should be noted that the effectiveness of these methods is likely significantly diminished against copepod ephippia.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
Although its origins are unknown, the nonindigenous status of this species is suggested by the fact that it belongs to a marine genus. Lesko et al. (2003) considers this exotic species to be variant of H. nunni, while others believe it is most likely a separate undescribed species, owing to differences in morphology and life history between H. nunni and H. nr. nunni (Horvath et al. 2003; Garza and Whitman 2004).
References
(click for full reference list)
Author:
Kipp, R.M., J. Larson, T.H. Makled, and A. Fusaro
Contributing Agencies:
Revision Date:
9/12/2019
Citation for this information:
Kipp, R.M., J. Larson, T.H. Makled, and A. Fusaro, 2024, Heteropsyllus nr. nunni Coull, 1975: 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=2659&Potential=N&Type=0&HUCNumber=DHuron, Revision Date: 9/12/2019, Access Date: 4/23/2024
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.