Predation risk of Double-crested Cormorants (Phalacrocorax auritus) on commercial catfish production in the Mississippi Delta
Item TypeGraduate Thesis
AdvisorDavis, J. Brian
Allen, Peter J.
Double-crested Cormorants (Phalacrocorax auritus) impact United States commercial aquaculture and are considered the greatest avian predators on catfish (Ictalurus spp.) aquaculture facilities in the Mississippi Delta. Recent changes in aquaculture practices, regulatory policies, and decreased overall hectares in production prompted this study that: 1) estimated abundance and distribution of cormorants at their night roosts using aerial surveys, 2) assessed cormorant consumption of catfish in relation to their night roost through cormorant collections and stomach contents analysis, and 3) updated a cormorant bioenergetics model with contemporary data to estimate catfish loss. Models estimated that 4.2 and 5 million cormorant forage days occurred during winters 2016-2018 with an average of 33% of their diet consisting of catfish, or 558.1 and 739.5 metric tons of catfish consumed by cormorants in winters 2016-2018. These results will inform wildlife managers about relationships between cormorant night roost locations and disproportionate consumption of catfish.