**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below.  For a copy of the full completion report, please contact the author via e-mail at thomas.pratt@dfo-mpo.gc.ca or via telephone at 705-941-2667. Questions? Contact the GLFC via email at frp@glfc.org or via telephone at 734-662-3209.**


In Situ Assessment of Lampricide Toxicity to Age-0 Lake Sturgeon



T. C. Pratt2, L. M. O’Connor2, T. B. Steeves3, B. Stephens3, M. Boogaard4, C. Kaye5


2 DFO-GLLFAS 1219 Queen Ste. East, Sault Ste. Marie, ON

3 DFO-SLCC 1219 Queen Ste. East, Sault Ste. Marie, ON

4 USGS 2630 Fanta Reed Rd., La Crosse, WI

5 USFWS-SLCC 3090 Wright St., Marquette, MI



July 2013




TFM and TFM/1 % niclosamide are selective lampricides used to control the Sea Lamprey (Petromyzon marinus), an invasive species in the Great Lakes. Age-0 Lake Sturgeon (Acipenser fulvescens), listed as threatened or endangered in both Canada and the United States, share similar stream habitats with larval Sea Lampreys and these streams can be targeted for lampricide applications in the early summer months on a 3 to 5 year cycle. Previous studies found that, for Lake Sturgeon less than 100 mm, the concentrations required to kill 50% of Lake Sturgeon (Lethal Concentration, LC50), and the Sea Lamprey Minimum Lethal Concentration (MLC, LC99.9) concentrations were very similar and expected age-0 sturgeon mortality from lampricide application was high. We conducted stream-side toxicity and in situ studies in conjunction with lampricide applications during 2010 and 2011 to determine if the laboratory results concurred with subjective observations during lampricide applications, namely, that there was very little Lake Sturgeon mortality in stream settings. In the bioassays we found the observed LC50 for Lake Sturgeon was higher than the predicted Sea Lamprey MLC. However, for two of the rivers, the LC50 and MLC were very close. In situ, we found that survival of Lake Sturgeon less than 100mm total length during 10 lampricide applications averaged approximately 80%, a rate that exceeds the laboratory values.