Verification of the spawning location of grass carp Ctenopharyngodon idella in the Sandusky River

Session: Poster Session

Patrick Kocovsky, U.S. Geological Survey, [email protected]
Nicole King, University of Toledo, Lake Erie Center, [email protected]
Christine Mayer, University of Toledo, Lake Erie Center, [email protected]
Song Qian, University of Toledo, [email protected]

Abstract

In June 2018, coincidence of a spawning event and a scheduled management action to capture adult Grass Carp permitted verification of their model-predicted spawning location. Fertilized Grass Carp eggs were collected at several sites from 3.3 km to 18 km downstream of the predicted spawning area 11-14 June. We used water temperature measured in the field at time of capture, developmental stage (± 1 stage), and published curves relating developmental time to water temperature to estimate time since fertilization for several hundred eggs. We then subtracted developmental time from capture time for each egg to determine the time the egg was fertilized and created a histogram of fertilization times. Second, two mature, diploid female and 14 mature, diploid male Grass Carp were captured by electrofishing conducted within the predicted spawning area during a prescribed management action conducted 12-14 June. Histograms of egg fertilization times overlapped with collection times for mature Grass Carp in the model-projected spawning area, verifying that spawning was occurring in the model-projected spawning area when adult Grass Carp were captured.