**ABSTRACT NOT FOR
CITATION WITHOUT AUTHOR PERMISSION.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 jluoma@usgs.gov. Questions? Contact
the GLFC via email at slrp@glfc.org or via
telephone at 734-662-3018.**
James A. Luoma2,
Nicholas J. Robertson3, Nicholas A. Schloesser2, Courtney
A. Kirkeeng2, Justin R. Schueller2, and Erica K.
Meulemans3
2U.S. Geological Survery, Upper Midwest
Environmental Sciences Center, 2630 Fanta Reed Road, La Cross, WI 540602
3Nortland College, 1411 Ellis Ave, Ashland, WI 54806
May 2020
ABSTRACT:
The binational Great
Lakes Fishery Commission sponsored Sea Lamprey Control Program effectively
utilizes a variety of lampricide tools to keep populations of parasitic sea
lampreys in the Great Lakes at levels that do not cause undue economic or
ecological damage. The most widely used active ingredient used in lampricide
formulations is 3-trifluoromethyl-4-nitrophenol (TFM). In typical treatments, a
liquid TFM formulation is applied to lamprey producing
streams continuously for 10–14 hours to produce a moving block of
lampricide-treated water that kills larval lamprey before they metamorphose
into their parasitic lifestage. In many smaller
tributaries of dendritic streams a solid bar formulation of TFM is used to supplement the mainstem
treatment block. These supplemental TFM bar applications are coordinated with
the arrival of the mainstem lampricide to prevent
larval sea lamprey from seeking refuge in untreated waters and surviving the
treatment. TFM bars are produced from formulated surfactants
and designed to release TFM over an 8–10-hour period, depending on water
temperature and velocity. However, some of the surfactants have been discontinued resulting in the reformulation of the
TFM bars multiple times. As a result of these
reformulations, TFM bar performance has declined.
An
experimental surfactant-free solid TFM tablet formulation was
developed as a potential replacement for TFM bars. Release of TFM from
the experimental tablets was evaluated using
replicated laboratory dissolution trials conducted at three water temperatures
and three water velocities. A continuous-flow laboratory flume was used for the dissolution trials and the decay of the
tablets was modeled using logistic decay curves. Time required for the TFM tablet to decay 50 and 99% were compared among
the groups using a two-way analysis of variance. Post-hoc Tukey Honest
Significant Difference tests indicated that both water temperature and water
velocity influenced the decay of the tablet; however, neither water temperature
nor water velocity appeared to dramatically influence TFM
release. Results from this laboratory study indicate that the next stage of
evaluating the TFM tablets using field tests is warranted.