Document Type

Thesis - Open Access

Award Date

2015

Degree Name

Master of Science (MS)

Department

Natural Resource Management

First Advisor

Brian Blackwell

Abstract

A statewide gear comparison was performed in South Dakota during 2013 and 2014 between current South Dakota Department of Game, Fish and Parks (SDGFP) sampling gears (i.e., gill nets and modified fyke nets) and their equivalents described in Standard Methods for Sampling North American Freshwater Fishes (Standard). Adopting Standard gears would provide uniform gear specifications for annual sampling statewide, facilitate data sharing within South Dakota and beyond, and allow for large-scale spatial and temporal analyses relevant to researchers and managers. Sampling was divided between non-Missouri River (non-MR) and Missouri River (MR) systems because gill nets used by SDGFP to sample Missouri River reservoirs were double the length of gill nets used elsewhere in the state and were constructed of multifilament twine instead of monofilament twine. In non-MR systems, SDGFP gill nets had higher catch per unit effort for most species commonly indexed with gill nets including Walleye and Yellow Perch while Standard gill nets selected for larger individuals of most species. In MR systems, gill net CPUE was higher for almost all species captured using SDGFP multifilament reservoir gill nets because SDGFP nets were over three times longer than Standard nets. Standard gill nets with additional large bar-mesh panels selected for larger individuals of most species, including Walleye, than did SDGFP reservoir nets. Monofilament was more efficient than multifilament for almost all species investigated. Modified fyke net catches were similar for many species between net types though Standard nets captured more Black Crappies and SDGFP nets captured more Black Bullheads. Standard modified fyke nets tended to select for larger Black Crappie and Bluegills. In both MR and non-MR systems, conversion factors for lakewide catch per unit effort were developed for each gear type using regression analysis to allow for conversion of historic catch data into equivalent Standard CPUE. Estimates of species diversity and evenness did not differ between SDGFP or Standard gears. Indirect estimates of gill net selectivity were performed for 18 species sampled using Standard gill nets to identify shape of species and mesh-specific selectivity curves, approximate peak modal efficiency for each mesh, and identify overall shape of selectivity curves for all meshes combined. Comparisons of modified fyke nets with restricted and unrestricted throat configurations revealed that catch per unit effort was higher for nets with restricted throats. Subsequent escapement trials confirmed that most Black Crappie and Bluegill escaped from modified fyke nets with unrestricted throats. Together, the paired gear comparisons between SDGFP and Standard gears and additional investigations of Standard gears provided the necessary information to allow for a potential statewide transition to North American Standard sampling gears.

Library of Congress Subject Headings

Lakes--South Dakota

Fishing--South Dakota

Fishing--South Dakota--Missouri River

Fishing tackle

Description

Includes bibliographical references (pages 26-33)

Format

application/pdf

Number of Pages

192

Publisher

South Dakota State University

Rights

Copyright © 2015 Bradley J. Smith. All rights reserved.

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