Effect of Fishing Effort on the Catchability of Largemouth Bass
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Automated Template A: Created by James Nail 2011 V2.02 Effect of fishing effort on the catchability of largemouth bass By Matthew Glenn Wegener A Thesis Submitted to the Faculty of Mississippi State University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Wildlife, Fisheries, and Aquaculture Science in the Department of Wildlife, Fisheries and Aquaculture Mississippi State, Mississippi May 2013 Effect of fishing effort on the catchability of largemouth bass By Matthew Glenn Wegener Approved: _________________________________ _________________________________ Harold L. Schramm, Jr. Donald C. Jackson Professor of Wildlife, Fisheries, and Professor of Wildlife, Fisheries, and Aquaculture Aquaculture (Director of Thesis) (Committee Member) _________________________________ _________________________________ Leandro E. Miranda Jason Wesley Neal Professor of Wildlife, Fisheries, and Associate Extension Professor of Aquaculture Wildlife, Fisheries, and Aquaculture (Committee Member) (Committee Member) _________________________________ _________________________________ Eric D Dibble Bruce D. Leoplold Professor of Wildlife, Fisheries, and Professor and Head of Wildlife, Aquaculture Fisheries, and Aquaculture (Graduate Coordinator) _________________________________ George M. Hopper Dean of Forest Resources Role (Graduate Coordinator) Name: Matthew Glenn Wegener Date of Degree: May 10, 2013 Institution: Mississippi State University Major Field: Wildlife, Fisheries, and Aquaculture Science Director of Thesis: Dr. Harold L. Schramm, Jr. Title of Study: Effect of fishing effort on the catchability of largemouth bass Pages in Study: 60 Candidate for Degree of Master of Science The effect of fishing on the catchability of a population receiving intense angler effort has long been debated but not measured. This study evaluated the effect of fishing effort on catchability of adult largemouth bass Micropterus salmoides and determined whether catchability was affected by a period of no fishing. Eight, 0.5-2.0 ha impoundments were fished once a week for 0.4 angler hours per hectare per week during two successive May-October fishing seasons to evaluate whether catch rates differed between populations fished continuously and populations with the fishing season interrupted by a 2-month period of no fishing. Mixed-model analysis indicated effort significantly decreased catch rate (F 4, 298 = 16.53; P < 0.001). Pair-wise comparisons indicated change in catch rate was not significantly different (t = 1.52; P = 0.13) between the first 8 weeks and the final 8 weeks of fishing for ponds that received a 2-month layoff. DEDICATION My thesis is dedicated to my parents, Glenn and Mary Wegener, and to the late Matthew Spickard. My father taught me the value of the great outdoors and gave me my first opening into the world of fisheries. My mother instilled in me the power and drive to finish anything I started, no matter how long it takes. Matthew Spickard opened my eyes to a world outside of fisheries management and showed me what it meant to be an aquatic biologists. We spent many hours on the water and in the classroom discussing our futures, but no one knew his would end so prematurely. Anyone that knew Matt knows that he will never be forgotten. ii ACKNOWLEDGEMENTS I would like to thank Patrick Mirick, Trey Dunn, Nathan Kuntz, Jason Herrala, Jonathon Fleming, Matthew Spickard, Bradley Sartain, Dr. Wes Neal and Dr. Hal Schramm for helping with field work. It wasn’t always easy skipping work to go fishing on a hot, Mississippi summer day. These guys never complained…that much. Additional thanks to Dr. Hal Schramm and Dr. Wes Neal for helping with sample design. Dr. Hal Schramm, thank you for reading all the versions of my thesis; good and bad. Statistical help was given by Dr. Pat Gerard and Patrick Mirick. Other thanks goes to the Victorian Inn in Iuka, Mississippi that provided a nice place to stay at an affordable rate during our weekly sampling trips and to Jerry Hazelwood with MDWFP who helped grant access to my study site. Also, thanks to Pradco Lures, Arkansas who provided most of the fishing equipment used in this project. Funding was provided by the USGS Mississippi Cooperative Fish and Wildlife Research Unit. Finally, I would like to thank the Department of Wildlife, Fisheries, and Aquaculture for the support needed to complete my degree. iii TABLE OF CONTENTS DEDICATION .................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................... iii LIST OF TABLES ...............................................................................................................v LIST OF FIGURES ........................................................................................................... vi CHAPTER I. INTRODUCTION .............................................................................................1 II. METHODS ........................................................................................................5 Study ponds ........................................................................................................5 Population characteristics ................................................................................10 Data analysis ....................................................................................................21 III. RESULTS ........................................................................................................26 Population characteristics ................................................................................34 Effect of effort on catch rate ............................................................................38 The effect of the 2-month period of no fishing on total catch .........................39 IV. DISCUSSION ..................................................................................................42 LITERATURE CITED ......................................................................................................54 iv LIST OF TABLES 1 Characteristics of northeast Mississippi study ponds in 2008-2009 ....................7 2 Lures used during the study on northeast Mississippi ponds in 2008- 2009.......................................................................................................... 9 3 Weight-length relationship of largemouth bass in northeast Mississippi ponds collected from spring 2009 electrofishing samples .....................15 4 Start and end sizes used in bioenergetics model to predict growth of largemouth bass in northeast Mississippi ponds. ...................................16 5 Population characteristics of stock-size (>200 mm TL) largemouth bass estimated in spring 2009 and 2010 in northeast Mississippi ponds. .....................................................................................................18 6 Total lengths (TL) of recaptured (observed) and modeled (predicted) PIT-tagged largemouth bass using a bioenergetics model of largemouth bass in northeast Mississippi ponds in 2008-2009 ..............30 7 Mean catch rate of week-1 recruited largemouth bass in eight northeast Mississippi ponds in 2008-2009 .............................................................33 8 Proportional size distribution (PSD) estimated from angler-caught fish and electrofishing samples in 2008-2010 in northeast Mississippi ponds. .....................................................................................................35 9 Total lengths and growth rates of largemouth bass estimated from back- calculated lengths collected in spring of 2010 in northeast Mississippi ponds ...................................................................................36 10 Angling information for largemouth bass caught in northeast Mississippi ponds 2008-2009................................................................. 41 v LIST OF FIGURES 1 Weekly maximum (solid-black line) and minimum (solid-gray line) surface-water temperatures measured with a YSI meter (model 556) in eight northeast Mississippi ponds during 2008-2009. ...............14 2 Predicted growth in weight (top graph) from bioenergetics model of largemouth bass in northeast Mississippi ponds in 2008-2009 ..............27 3 Mean catch rates of largemouth bass in eight northeast Mississippi ponds in 2008-2009 ................................................................................29 4 Mean catch rate of largemouth bass ≥ 200 mm TL in eight northeast Mississippi ponds fished for 2.5 angler-h ha-1week-1 for 24 weeks during May-October 2008 and 2009. ..........................................31 5 Mean catch rate of largemouth bass ≥ 200 mm TL in eight northeast Mississippi ponds fished 2.5 angler-h ha-1week-1 during weeks 1-8 and 17-24 of the May-October fishing seasons in 2008 and 2009 ........................................................................................................32 vi INTRODUCTION Numerous predator-prey combinations have been stocked in small impoundments, but the largemouth bass (Micropterus salmoides)-bluegill (Lepomis macrochirus) combination is often recommended by fisheries managers and has proven suitable to provide sustainable fishing opportunities throughout much of North America (Modde 1980; Schramm and Willis 2012). However, stable forage supply and broad size distributions of largemouth bass and bluegill are needed for greater