SEAFWA 2018

AUTHORS: Stephen A. Clements, Brian Davis – Mississippi State University; Brian S. Dorr, Katie C. Hanson-Dorr – USDA/Wildlife Services/National Wildlife Research Center; Luke A. Roy, Auburn University; Anita M. Kelly, University of Arkansas at Pine Bluff; Carole Engle, Virginia Tech University; Scott C. Barras, USDA/Wildlife Services

ABSTRACT: Research is needed to address the growing concerns of Arkansas’ commercial baitfish and sportfish producers regarding the perceived increase in consumption of fish by lesser scaup (Aythya affinis) and greater scaup (Aythya marila); hereafter, scaup. The goals of our study were to estimate the distribution and abundance of piscivorous waterbirds, including scaup, on bait- and sportfish farms during fall-winters 2016-2017, and compare our contemporary results with unpublished surveys conducted from 2004 to 2005. Additionally, we aimed to estimate the amount of fish consumed by scaup foraging on commercial bait- and sportfish ponds. We surveyed approximately 800 baitfish and sportfish ponds (n = 15 individual farms) in Lonoke and Prairie Counties, Arkansas in winter 2016-2017. Accompanying these surveys, we also collected 294 foraging scaup from ponds. We removed and identified all food items in the gastrointestinal tract above the gizzard and taxonomically sorted, dried, and weighed each sample. All gizzards were examined for presence or absence of fish parts. We detected fish parts in 2% of scaup examined. A generalized linear mixed model fitted to previous and current survey data showed that scaup abundances were significantly higher on golden shiner ponds than ponds containing fathead minnows, goldfish, or sportfish. Our model indicates a significant decrease in scaup abundances during the contemporary surveys, which we attribute to the mild 2016-2017 winter. Our data will be vital in estimating the economic impact of fish loss to scaup foraging in these Arkansas ponds, and reveal potential management strategies to reduce fish predation by scaup.