Effects of Management Practices and Environmental Factors on Largemouth Bass Abundance in Illinois Inland Lakes

Ralf Riedel,Peter Bayley,Douglas Austen

doi:10.4236/nr.2017.83013

Abstract

An understanding of the relative importance of natural factors and management practices affecting largemouth bass (Micropterus salmoides) abundance is key for enhanced angling. Standardized fish surveys, management practices, and environmental data were available from 42 man-made, inland lakes between 1960 and 1991. Management practices tested were largemouth bass stocking, lake rehabilitation, water level manipulation, aquatic vegetation controls, small fish removal, and changes in length limits of harvestable fish. Environmental factors not controlled by management were spring water influx, growing and cooling degree days, and snow depth. Lake rehabilitation (complete drainage and reflooding), changes in length limits, and aquatic vegetation controls were the only significant factors affecting largemouth bass abundance. The largest effects were due to lake rehabilitation, which increased next-year young largemouth bass numbers by 566% on average, and more restrictive limits on harvestable size, with an increase of up to 440% in adult numbers.

Highlights

The need for incorporating environmental processes into fisheries management is being increasingly recognized as we gain insight into the complexities and interrelations of ecosystems
We investigated in this paper the efficacy of current largemouth bass management in light of natural environmental variation in an attempt to shed some light into the degree of con
The strongest evidence of management practices affecting the age-1 response variable was for lake rehabilitation

Summary

Introduction

The need for incorporating environmental processes into fisheries management is being increasingly recognized as we gain insight into the complexities and interrelations of ecosystems. Environmental effects outside the control of managers may overwhelm the effects of fisheries management [2], making fish abundance appear to fluctuate unpredictably and irrespective of management interventions. If uncontrolled environmental effects are major determinants of fish abundance, management effectiveness may decrease, potentially leading to failure. If we can better understand the effects of management and environmental factors on fish, estimating the cost-effectiveness of management scenarios may be attainable

Methods

Results

Conclusion