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Tuesday, January 30 • 10:20am - 10:40am
ASIAN CARP & OTHER AQUATIC INVASIVES: Grass Carp Spawning in Lake Erie Tributaries; When and Where?

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AUTHORS. Nicole King, University of Toledo Department of Environmental Sciences and Lake Erie Center; Patrick M. Kocovsky, U.S. Geological Survey, Lake Erie Biological Station; Christine Mayer, University of Toledo Department of Environmental Sciences and Lake Erie Center; Song Qian, University of Toledo Department of Environmental Sciences and Lake Erie Center

ABSTRACT. Invasive grass carp have been present in the Great Lakes since at least the early 1980’s. Although occasional individuals have been captured, it was assumed that most were sterile escapees from stocked ponds. However, spawning was documented in the Great Lakes in 2015 with the collection of eight eggs from the Sandusky River, Ohio, a Lake Erie tributary. In 2016 no eggs were found despite extensive effort, likely because no high discharge events occurred, and grass carp, like some other non-native carps, tend to spawn during high flows. Monitoring continued in 2017 with increased sampling effort including the addition of a mid-water net and adaptive sampling after egg detection to follow the spatial extent of the egg mass. In 2017 the Sandusky River yielded 7,000+ eggs during two high flow events. Catch per unit effort was substantially higher in 2017 than in 2015. The earliest developmental stage (stage three, stage one= no cell division, thirty= hatch) occurred at the most upstream site and the latest developmental stage (twenty five) near the river mouth. The pattern of egg stages and spatial distribution over time indicated spawning likely occurred several times. We also noted significant differences in both vertical and lateral egg distribution throughout the river.  Further, prospective sampling in the Maumee River, Ohio, during a high flow event yielded five eggs, the second documented location of Grass Carp spawning the Great Lakes.  Only two of the Maumee River eggs could be identified to a developmental stage; both were of late developmental stage (twenty three) near Perrysburg, Ohio. Grass carp spawning has now been documented in multiple years and in multiple Great Lakes tributaries.  Therefore, it is now crucial to determine if, where, and when recruitment is occurring in order to limit further population growth of grass carp.

Tuesday January 30, 2018 10:20am - 10:40am
103A

Attendees (2)