Report of a new aquatic invasive species – May 6, 2010

Report by Darrin Hoverson – MN DNR, Invasive Species Specialist

Invasive Species Banded Mystery Snail ( Viviparus georgianus )

Location: Bad Axe Lake (DOW29020800), Hubbard County, Minnesota

Date Sampled: May 5, 2010

Sampled by: MN DNR Invasive Species Intern – Jacob Hanson

Sampled with: collection along the shoreline of the lake below the Boy Scout Camp

Figure 1. Banded mystery snail

Identification: Viviparus georgianus has a relatively globose, dextral shell with 4–5 whorls separated by distinct sutures. The outer lip of the shell is quite thin (Jokinen 1992) and the overall coloration is yellow-green. There are abundant rows of hairs with distinctly hooked ends and ridges on the periostracum. The umbilicus is narrow or not apparent, and the operculum is round to oval with concentric circular markings that radiate from an off-centre origin located towards the top left. There are always 4 darkly pigmented bands that wrap around the shell spirally, but which are sometimes only visible from inside (Macki et al. 1980; Jokinen 1984; Jokinen 1992).

Size: One-year old snails are 12–17 mm high; at 2 years, 17–21 mm high; and at 3 years, 21–30 mm high (Lee et al. 2002). The maximum height is 45 mm (Jokinen 1992).

As of 05/5/10 banded mystery snails had not been previously identified or reported in Bad Axe Lake