1Mott, L, 1Poulton, Barry C., 1Kroboth, P, 1Chapman, D, 1George, A., 2McMurray, S., 2Faiman, S.
1U.S. Geological Survey, Columbia Environmental Research Center, 2Missouri Department of Conservation, Conservation Research Center
Black Carp (Mylopharyngodon piceus) were imported in the 1980s from eastern Asia to Missouri, Arkansas, Louisiana, and Mississippi to control disease-carrying snails in aquaculture ponds. Black carp escaped from these facilities and have spread throughout the lower Mississippi River basin. This invasive molluscivore typically consumes bivalves and gastropods which are often crushed with their molariform pharyngeal teeth as they are ingested. During 2017, we examined 109 gastrointestinal tract samples from black carp captured by commercial fishers to inventory diet items and help understand their feeding ecology. As a continuation of this effort, we examined an additional 221 black carp caught during 2018-2019. From these diet samples, we identified 63 aquatic animal taxa (27 mollusks, 30 insects, 6 other invertebrates) and organic matter components (detritus, nuts, seeds). Approximately 59% of samples were empty or only contained intestinal flukes. Snails (13.6%), bivalves (21.3%), and aquatic midges (12.7%) had the highest incidence in non-empty stomachs. Examination of 2018-2019 fish identified six additional unionid mussel species consumed by black carp, including two Missouri Species of Conservation Concern. Taxa accumulation curves showed diet richness in black carp steadily increased over time as more samples were examined from newly captured fish, indicating opportunistic feeding. Results demonstrate black carp are not obligate molluscivores and consume a diverse diet, although fish and odonates were absent from samples. An increased number of documented mollusk taxa in the diet highlights the potential threat of this invasive species on imperiled unionid mussels in the Mississippi River basin.