Date of Award
Master of Science (MS)
Keith D Koupel, Bryan T Drew, Richard S Holland
Cove;Cove Disconnection;Fish Community;Sediment Berm;Water Quality;Zooplankton
Sediment berms of various heights have developed in the mouths of several coves within Harlan County Reservoir due to a combination of sediment deposition and lateral drift of eroded sediments. These berms can isolate coves from the main reservoir if the berm height is greater than the water elevation of the reservoir. Disconnection of coves may impact water quality, zooplankton, and fish within the isolated reservoir habitats. This study will examine differences in water quality parameters, zooplankton communities, and fish assemblages between disconnected coves, connected coves and the main reservoir. Water quality parameters related to water clarity and productivity differed between habitat types, with disconnected coves having higher turbidity and relative chlorophyll a readings, and lower secchi depths compared to the main reservoir. Connected coves had intermediate values between disconnected coves and the main reservoir. Disconnected coves also had increased densities of zooplankton. Zooplankton assemblages differed between habitats. Both cove types had increased abundance of rotifers within their assemblages, however this was more pronounced in disconnected coves. The main reservoir had increased Daphnia spp. compared to disconnected coves. Ordination of the zooplankton assemblages showed high community consistency within the main reservoir, compared to more variability within connected and disconnected coves. Connected coves had increased species richness and Shannon’s diversity compared to disconnected coves. Jaccard’s similarity index indicated that habitats were similar in species composition, however their assemblages had low similarity based on Renkonen Similarity Index. Ordination of the fish community showed connected coves had distinct fish assemblages compared to disconnected coves. Disconnected coves had large variability in fish assemblages. White Bass, Freshwater Drum, Channel Catfish, Gizzard Shad, River Carp Sucker, Walleye, Shortnose Gar, Northern Pike, Western Mosquitofish, Largemouth Bass, and Red Shiner were indicator species for connected coves. Disconnected coves had no species that were indicators.
Mason, Brian Edward, "Comparison of Abiotic and Biotic Factors Between Coves of Varying Connection to Harlan County Reservoir, Nebraska" (2021). Biology Theses, Dissertations, and Student Creative Activity. 1.