Midwest Fish & Wildlife Conference 2019

AUTHORS: Nick Kramer, Kansas Department of Wildlife, Parks, and Tourism

ABSTRACT: Gill nets are one of the most popular gears implemented to assess fish populations in North America. Ease of construction and low maintenance has led to their success and widespread implementation in the field of fisheries management. The characteristics of a gill net, along with the size and shape of the fish affect how capture occurs (i.e., wedging, gilling, tangling, or a combination). Many studies have been completed on selectivity of various sizes of mesh. Despite the importance of mesh size, the shape of the mesh can also be altered by modifying the hanging ratio which in turn will affect the catchability of fishes with differing body shapes. Additional studies have demonstrated the effectiveness of hobbling or tying down gill nets. This creates more of a “baggy” net which studies have shown to capture a wider size range of fish and may increase catches of species that could easily become tangled due to external protrusions (e.g., Channel Catfish or Paddlefish). In recent years, Kansas Department of Wildlife, Parks, and Tourism biologists have become interested in managing Blue and Flathead Catfish and have placed an increased priority on sampling these species; however, the biologists currently have little insight into fully representative population parameters due to standardized sampling gear that does not capture larger individuals. Thus, the objective of this study is to evaluate the effectiveness of various gill net designs to sample fish populations in Kansas impoundments with special consideration given to species of interest for biologists (e.g., Blue Catfish, Flathead Catfish). Year one of this study found differences in catch rates for some commonly assessed species. These differences were further examined in year two of the study by expanding the sample size; in both number of sets and number of reservoirs.