Modeling Effects of Length Limit Regulations on Riverine Populations of Channel Catfish

Abstract

Channel Catfish Ictalurus punctatus is an important species among anglers in North America. Channel Catfish management strategies vary greatly in the United States and Canada, and there are few examples of regulations aimed at improving size structure in the literature. The goal of this study was to model the response of Channel Catfish to changes in regulations that meet specific management objectives. We modeled a suite of regulations to determine if minimum length limits or a protected slot limit could be used to improve size structure or avoid growth overfishing of Channel Catfish in a large river. We modeled three minimum length limits (304, 356, and 406 mm) and a 356–456-mm protected slot limit to assess the effectiveness of each at delaying or eliminating growth overfishing and increasing the number of quality-sized fish in the Missouri River, Nebraska. Our models indicated a 406-mm minimum length limit could be used to avoid growth overfishing until exploitation rates were greater than 45% and that both minimum length limits and slot limits could be used to increase the number of quality-sized fish by up to 4 times the number under current regulations.

Received April 6, 2015; accepted October 27, 2015

ACKNOWLEDGMENTS

The authors thank R. Holland, V. Travnichek, J. Spurgeon, and two anonymous reviewers who provided reviews and comments on early versions of this manuscript. We also thank Nebraska Game and Parks Commission employees who contributed to the 1998–2008 field work, as well as University of Nebraska students and employees who contributed to 2009–2013 field work. Funding for this project was provided by the Nebraska Game and Parks Commission.