In Situ Assessment of Lampricide Toxicity to Age-0 Lake Sturgeon in the Great Lakes

In the Great Lakes, sea lampreys are controlled by the larvicide TFM. Previous lab studies had demonstrated that TFM can be toxic to lake sturgeon <100 mm. In 2008 a Lake Huron tributary was treated to compare age-0 survival to two TFM treatments: a) Sturgeon Protocol, 1.2 x MLC, a TFM treatment designed to reduce toxicity to age-0 lake sturgeon, and b) Full Treatment Protocol, 1.4 x MLC, the standard treatment. A total of 10 cages were distributed in each treatment and 10 cages were set as controls. Fish ranged in size from 57 – 101 mm. Survival rates were not statistically different (p = 0.414) between either treatments or the control: survival was high (93%). Between 2010 and 2011, this study was expanded to nine additional streams in Lakes Superior, Huron, and Michigan using the standard treatment protocol. 20 cages were distributed in each treatment with lake sturgeon ranging in size from 25-120 mm. Sturgeon ranging in size from 35 – 120 mm survived. Total survival ranged from 45 to 100%, with 89% of the rivers having 60% or better. Overall, lake sturgeon of smaller size than predicted by Boogaard et al (2006) survived in all lampricide applications.