Dr. Mark Luttenton of Grand Valley St. University and a team of experts did some field work recently in response to the recent mud snail discovery below the Grayling Hatchery. Please read Mark’s report below. The report was sent to Anglers President, Tom Baird among others from MITU, TU Mason Griffith chapter, MDNR, and MDEQ.
Greetings,A group of 6 (Terry L, Steve S, Jim W, Austin (works with Steve), Justin (works with me), and myself) surveyed four additional locations for mud snails on Sunday, they included: Gates Lodge, Burton’s Landing, Grayling Park, and just upstream of North Down River Road. Sites previously surveyed are: behind the hospital, the Main Branch below the East Branch confluence, the Main Branch above the East Branch confluence, between the I-75 bridge and Wilcox Bridge Rd., immediately below the hatchery, and halfway between the hospital site and the confluence with the Main Branch.The Main Branch sample sites survey on Sunday were selected because they are popular access points for fishing and canoeing/kayaking. We spent approximately 40 minutes at each site and sampled the majority of habitat types at each location. This gave us approximately 240 minutes of effort at each site. We did not find mud snails in any of our collections on Sunday.Thus far, we have only found mud snails immediately below the hatchery, behind the hospital, and halfway between the hospital site and the confluence with the Main Branch. The highest densities appear to be associated with the sites that are farthest upstream.I have also received a note back from Joe Holumzki at USGS in Menlo Park, CA. Joe worked on mudsnails in NZ. Here is his response;“Terry Short and I looked at the snails you sent. We think they’re Potamopyrgus antipodarum, the NZ mudsnail, smooth-shelled morph. The snails you sent are nearly morphologically identical to an invasive population I’ve sampled in Pilarcito Creek on the coast here in CA.”Please let me know if you have any questions,Cheers,MarkMark R. Luttenton, Ph.D.Associate Dean of the Graduate SchoolProfessor of BiologyGrand Valley State University306 C DeVos Center401 W. Fulton StreetGrand Rapids, MI 49504