Implementation of grass carp adaptive management response actions in Lake Erie

Session: Invasive Species (3)

Lucas Nathan, Michigan Department of Natural Resources, [email protected]
Kelly Robinson, Michigan State University, [email protected]
Seth Herbst, Michigan DNR-Fisheries, [email protected]

Abstract

Grass Carp Ctenopharyngodon idella, a non-native herbivorous fish species, has the potential to alter the Great Lakes ecosystem by consuming large amounts of native aquatic vegetation. The first fertilized Grass Carp eggs were collected in Lake Erie in 2015, emphasizing the urgency of implementing control responses to limit future spread and population growth. An adaptive management process was initiated in 2016 to evaluate potential response actions and elucidate key uncertainties. Grass Carp catchability (i.e. gear efficiency, detection probability), abundance, and seasonal distribution were identified as key uncertainties that would help refine future control approaches. Beginning in 2018, our multi-institution collaboration implemented experimental control actions to reduce some of these uncertainties while conducting Grass Carp control efforts in the Michigan waters of Lake Erie. We used a combination of traditional and molecular (environmental DNA, eDNA) detection methods to evaluate gear efficiency and document seasonal occupancy of Grass Carp. To date, no Grass Carp have been captured as part of our gear efficiency evaluation, however capture of surrogate species indicates that detection probabilities are similar among the gear types. Information gained from 2018 will be used in the next iteration of the adaptive management cycle to inform future response options.