Date of this Version
Wiley, C. W. 2013. Exploitation of channel catfish in Nebraska flood-control reservoirs. Master's thesis. University of Nebraska-Lincoln, Lincoln, Nebraska.
Channel catfish Ictalurus punctatus, is a popular sportfish in North America, and is the third most-sought fish species in Nebraska. Exploitation rates of channel catfish populations have been estimated to be substantial in states neighboring Nebraska. Despite the popularity of channel catfish, little is known about the exploitation of channel catfish populations in Nebraska. The objectives of this study were to estimate the exploitation rates of channel catfish populations, identify the length bias of angling for channel catfish, and identify the self-imposed length limits for channel catfish at flood-control reservoirs of Nebraska. The software package Program Mark was used to analyze mark-recapture data for channel catfish captured with tandem-set hoop nets to estimate channel catfish population sizes at ten reservoirs during 2011-2012. Angler catch and harvest of channel catfish was estimated at eight reservoirs during 2011-2012 using data collected from angler interviews. Exploitation rates were estimated by dividing the number of channel catfish harvested by the number of channel catfish available in the population. Estimates of exploitation rate ranged from 0% at three reservoirs to 73% at one reservoir. Given the imprecision associated with the estimates of channel catfish population size and angler harvest of channel catfish, we suggest the investigation of other approaches to estimate exploitation rates of channel catfish populations in the future. Recreational angling was length biased, with angling selecting intermediate lengths of channel catfish regardless of harvest regulations or sizes of channel catfish available in the population. I determined self-imposed length limits for channel catfish by modeling probability of harvest of captured channel catfish based on length using a generalized linear mixed model. I determined that an interaction between whether an angler was angling from a boat or the bank and angling during the night or during the day was the most appropriate model for explaining self-imposed length limits for channel catfish. Self-imposed length limits for channel catfish ranged from 63 cm total length for anglers angling during the day from the bank to 90 cm total length for anglers angling during the night from a boat.
Advisor: Kevin L. Pope