**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**
Evaluation of within stream lampricide distribution as a measure of treatment effectiveness in controlling larval sea lampreys using enhanced treatment regimes in Great Lakes tributaries
We evaluated stream concentrations of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) during six sea lamprey control treatments to evaluate the use of enhanced treatment strategies with respect to the within stream distribution of the lethal dose of TFM. TFM concentrations were monitored at three sites within the treated area of each stream corresponding to a straight section, a deep pool or bend, and an area of slack-water and/or extensive aquatic vegetation. At each sampling site, hourly water samples for TFM analysis were collected along longitudinal transects of the stream from sampling locations spaced horizontally and vertically within the water column. Water chemistry analyses of pH, temperature, and alkalinity were also measured hourly at each location within the sampling site. The enhanced concentration treatment strategy (10% above normal treatment concentrations) applied to the Rifle, Bad, and Manistique River systems achieved TFM concentrations of about 1.6 X the predicted sea lamprey minimum lethal concentration (MLC) and ranged from 1.3 X to 2.0 X the MLC. Lampricide block duration (length of time the treatment achieved TFM concentrations > sea lamprey MLC) averaged 11.7 h and ranged from 10 to 13 h indicating TFM concentrations were of sufficient magnitude and duration for effective control. The enhanced duration treatment strategy applied to the Brule, Cedar, and Carp River systems achieved TFM concentrations of about 1.2 X the predicted sea lamprey MLC and ranged from 1.0 X to 1.35 X the MLC. Lampricide block duration averaged 12.8 h and ranged from 11 to 14 h indicating TFM concentrations were of sufficient magnitude and duration for effective control. A comparison of TFM block profiles from the sampling locations within each transect indicated that TFM concentrations, for the most part, were evenly distributed throughout the water column within 3 h of detection at all sampling sites on all six treatments evaluated. There were a number of sites where the stream banks required an additional 1 to 2 h to reach target treatment concentrations compared to the middle of the stream. However, TFM concentrations were maintained for 1 to 2 h longer along the stream banks indicating the overall block duration did not differ between sampling locations within these sites.