**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**



Study of issues related to stream pH and lampricide treatments


Michael A. Boogaard1, Jane E. Rivera1, Terrance D. Hubert1, David A. Johnson2, Alex F. Gonzalez3, and Brian E. Stephens4


1U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI, 54603

 2U.S. Fish and Wildlife Service, Marquette Biological Station, 3090 Wright Street, Marquette, MI, 49855

 3U.S. Fish and Wildlife Service, Ludington Biological Station, 229 S. Jebavy Drive, Ludington, MI, 49431

 4Department of Fisheries and Oceans, Sea Lamprey Control Centre, 1 Canal Drive, Sault Ste. Marie, ON, P6A 6W4



At the October 2001 meeting of the Lampricide Control Task Force (LCTF), two pre-proposals and two requests for studies related to pH and lampricide toxicity were presented and discussed. The LCTF proposed combining the studies into a single proposal. A subgroup of the LCTF was asked to develop a combined research proposal. This resulting proposal had the following objectives: (1) define the influence of pH and total alkalinity on the toxicity of niclosamide to larval sea lampreys (Petromyzon marinus); (2) investigate the efficacy of extended-length/low-concentration blocks of lampricides for killing sea lampreys and assessing safety for nontarget fishes; (3) provide agents with a system of defining lampricide concentrations lethal to sea lampreys (LC99.9s) for waters of significantly varying pH that maximizes mortality to sea lampreys while minimizing nontarget effects; and (4) investigate causes of suppression of pH during lampricide treatments of some streams. This report describes research conducted on Objectives 2 and 3 at the U.S. Geological Survey’s Upper Midwest Environmental Sciences Center. Completion reports on Objectives 1 and 4 have previously been submitted. In this study, 12-h and 24-h toxicity trials with the lampricide 3-trifluoromethyl-4-nitrophenol were conducted on larval sea lampreys at varying starting points within a simulated one-unit diurnal pH cycle. Predictive methods developed in this study indicate sea lamprey LC99.9s for 12-h treatments may vary by more than 2 fold depending on the starting point within a one-unit pH cycle while LC99.9s for 24-h treatments will vary by less than 1 fold under the same one-unit pH cycle. Based on these results, a 24-h treatment strategy would be more advantageous than a 12-h strategy both in terms of treatment effectiveness and nontarget safety.