May 7, 2011 - gizzard shad will have a positive (Hartman and Magraf 1992; .... Ameiurus melas, brook stickleback Culaea inconstans and johnny darter ...
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Influence of Gizzard Shad on Fish Community Ecology in Northeastern South Dakota Glacial Lakes
BY Justin Allen VanDeHey
A dissertation submitted in partial fulfillment of the requirements for the Doctor of Philosophy Major in Wildlife and Fisheries Sciences South Dakota State University 2011
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Acknowledgments I would like to thank my technicians Nick Peterson, Madeline Wedge, Jason Harris, Nate Stukel, Ryan Andvik, Bethany Galster and Tanner Pruess for all their assistance with field and laboratory work on this project, especially Nick Peterson would worked side by side with me for nearly 3 years. I would also like to thank many graduate students and faculty, past and present, from South Dakota State University especially Dr. Steve Chipps, Kris Edwards, Tom Bacula, Andrew Jansen, Mark Fincel, Dr. Jeff Jolley, Mark Kaemingk, Jen Gutscher, Dan James, Mike Greiner, Josh White, Dan Dembkowski, Will Schreck, Will French, Landon Pierce, Luke Schultz, Dr. Melissa Wuellner, and Dr. Katie Bertrand for assistance with the project. I would like to thank Todd Kaufman, Ryan Braun, Steve Kennedy, Mark Ermer, Ty Moos, Kyle Potter, and Bob Hanten from the South Dakota Department of Game, Fish and Parks for assistance with sample collection, and aid in fish stockings. Thanks to Bill Miller and Gene Galinat from South Dakota Game, Fish and Parks for providing additional gizzard shad data. Thanks to Dr. Dan Isermann for assistance with statistical analysis. I want to thank my committee members for challenging me during my tenure at South Dakota State and also for all their help on various parts of this project and all my other scholarly endeavors. I want to thank each of them individually for certain aspects. First, thanks to Dr. Brian Blackwell for all the help in the field, for borrowing me equipment, providing me with alternative launching sites, and for all the brainstorming and ideas he helped me develop. Thanks for helping me feel welcome to South Dakota and for allowing me to work on this project. Thanks to Dr. Michael Brown for his wisdom and guidance on statistical issues and SAS programming, guidance on
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becoming a better scientist, for all the help with AFS certification and helping me advance my career and for providing me with a wealth of knowledge on everything related to fisheries. You truly are a renaissance man of fisheries. Thanks to Dr. Brian Graeb for challenging me to never settle, to become a better scientist every day and for making me think about the big picture. Thanks for all the help you provided me on a day to day basis regarding everything from fish recruitment to handling students, to dog training and everything in between. You are a true friend and I am truly appreciate everything you have done for me. Finally, thanks to my advisor and mentor Dr. David Willis for taking a chance on a genetics lab rat, fostering scholarly thoughts, providing wisdom on everything related to fisheries, academia, professional advancement and for always having an open door despite your vast obligations. Thanks for being a “machine” and always getting manuscripts, dissertation chapters, proposals, presentations, abstracts and everything else back to me so rapidly. But most importantly thanks for helping me become the professional and the person that I am today. I am forever indebted to you and all my committee members for all your help. I want to thank my parents, family and friends for all your love and support over the last 30 years and for encouraging me to pursue my career and to stay in school. Thanks to Fenway, Ripken and Mays for always being happy to see me at the end of the day, no matter what kind of day I had and for being an ear to vent to. Last I especially want to thank my wife Breanna for encouraging me to chase my dreams, to never settle for second best for moving to South Dakota and for all the help along the way. Thanks Bre for all the hours volunteering in the lab, for keeping things on track at home so I could stay at work to meet that every approaching deadline, for humoring my
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dog obsession and most of all for your unwavering love. Without you I would never have been able to accomplish what I have today. Funding for this project was provided by Federal Aid in Sport Fish Restoration Project F-15-R, Study 1509, administered through South Dakota Department of Game, Fish and Parks.
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Abstract Influence of Gizzard Shad on Fish Community Ecology in Northeastern South Dakota Glacial Lakes Justin Allen VanDeHey May 7, 2011
Walleye Sander vitreus are the most popular sport fish in South Dakota, while yellow perch Perca flavescens are important both ecologically as prey for walleye and economically as an important sport fish themselves. Gizzard shad Dorosoma cepedianum are also an ecologically important species in many of the systems in which they occur. South Dakota is at the northwestern edge of the native range of gizzard shad and overwinter survival of shad is often limited. However, with recent climate warming gizzard shad have been experiencing overwinter survival in some South Dakota systems where it had not been previously documented. This overwinter survival could allow for a natural range expansion of gizzard shad in South Dakota. A resulting range expansion could have a variety of effects on the invaded systems. Walleye would likely prey on gizzard shad, which could increase their growth, condition and abundance. If sufficient gizzard shad are present they may even buffer yellow perch from predation by walleye potentially increasing perch survival and recruitment. However, the extent of competition between gizzard shad and yellow perch is unknown. The objectives of this study were to 1) estimate survival, reproduction and recruitment of gizzard shad in two northeastern South
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Dakota glacial lakes and 2) determine the impacts gizzard shad on the population dynamic rates and seasonal diets of both walleye and yellow perch in northeastern South Dakota glacial lakes. To determine the effects that gizzard shad had on walleye and yellow perch in northeastern South Dakota glacial lakes I performed whole lake manipulations on two northeastern South Dakota glacial lakes by introducing adult, pre-spawn gizzard shad in two subsequent years. Adult, pre-spawn gizzard shad were collected from Lake Sharpe, South Dakota and transported to East Krause and Middle Lynn lakes, Day County, South Dakota where they were stocked in May of 2008 and 2009. Both lakes are located in drainages where gizzard shad are native. Using a before-after-control-impact study design I monitored a total of three lakes (two treatments, one control; Lardy Lake) over a 4-year time period; 1 year pre-gizzard shad, 2 years with shad, and 1 year post-shad. Survival, reproduction and recruitment were assessed for all three species and growth, relative abundance, condition, size structure, seasonal diets and stable isotope signatures were assessed for both walleye and yellow perch throughout the study. For my first objective, gizzard shad reproduction was estimated through ichthyoplankton surface trawling to develop an index of abundance (number/100 m3). An index of juvenile abundance was developed by estimating the number of autumn age-0 gizzard shad collected during nighttime electrofishing (number of fish/h). Additionally, overwinter survival of adults was assessed by marking all adult gizzard shad stocked in 2009 to differentiate them from adult shad stocked in 2008. Adults were sampled
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simultaneously with walleye and yellow perch using both graded mesh gill nets and boat electrofishing. Additionally, as no adults were stocked in 2010, any adult or juvenile gizzard shad captured during 2010 would indicate at least some overwinter survival had occurred. Adult gizzard shad survived and successfully spawned in both lakes during both years. Larval gizzard shad were collected in both East Krause and Middle Lynn lakes during 2008 and 2009, although larval densities were lower than most other South Dakota systems containing gizzard shad. Larval gizzard shad survived to autumn (September) in both lakes in 2008 and were only documented in Middle Lynn in 2009. No overwinter survival of any gizzard shad was documented during the study as all adult shad captured during 2009 had been stocked that year and no shad were collected during 2010. For my second objective yellow perch reproduction was assessed similarly to gizzard shad through ichthyoplankton surface trawling and estimating the number of larval perch per 100 m3. Walleye reproduction was assessed using autumn nighttime electrofishing to develop an index of abundance (number of fish/h). Adult relative abundance (catch per unit effort; CPUE) of both yellow perch and walleye was estimated from spring (May) standardized graded mesh gill net surveys (number of fish/net night). Nets were set overnight and the mean number of fish per net night was estimated for each lake during each year. These fish were weighed, measured for total length, saggital otoliths were removed for aging, the majority had their stomachs removed for diet analysis and a
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piece of dorsal muscle tissue was removed from a subset of fish for stable isotope analysis (δ13C, δ15N). Walleye growth increased significantly in East Krause Lake during years when gizzard shad were present. Additionally, across most length categories and seasons mean Wr of walleye was the highest during years when gizzard shad were present, suggesting that shad had a positive impact on walleye growth and condition. Although relative abundance of walleye was lowest in the years when gizzard shad were present, no statistically significant differences were found in the relative abundance of walleye in East Krause throughout the study, suggesting that the improved growth and condition of walleye in East Krause was related to the presence of the additional prey fish (i.e., gizzard shad). Gizzard shad were present in the diets of walleye collected during the autumn 2008 sample and composed over 60% of the diets by weight during that sampling period. Thus, gizzard shad were a substantial component of walleye diets when available. Further, gizzard shad are more energetically beneficial than other prey fish present (i.e. yellow perch or fathead minnows Pimephales promelas), which would indicate they could have accounted for increases in growth and condition. Stable isotope analysis suggested that small yellow perch ( males) in all lakes during all years except in Lardy Lake in 2010 where growth of male and female perch was not significantly different. However, growth rates of male yellow perch were similar among all years in all lakes and growth of female perch was similar in all years in both treatment lakes suggesting that gizzard shad did not impact growth of perch in these systems. In general, yellow perch mean Wr was higher during 2007 and 2010 than other years, despite these years having higher relative abundance estimates. These results suggest that yellow perch growth and condition were not related to perch abundance during this study. For example, in East Krause mean CPUE ranged from 3 in 2008 to 49 fish/net night in 2010 yet growth did not differ between these years for either sex. Additionally, mean Wr of substock yellow perch collected in September was not related to larval abundances. Thus prey resources for yellow perch were likely not limiting in these systems, at least during the years of my study. One of the potential a priori concerns regarding stocking gizzard shad into these systems was the potential for competition with yellow perch for food resources, especially age-0 perch. No significant differences were present in mean Wr during any month of any
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year for substock yellow perch, the size most likely to compete with gizzard shad. Additionally, growth did not change between treatment and non-treatment years. These results coupled with no significant changes in growth of adult yellow perch indicate that gizzard shad likely did not negatively affect perch in these systems. While yellow perch relative abundance was lowest in Middle Lynn and East Krause during years where gizzard shad were present, the same pattern in CPUE existed in Lardy Lake where no gizzard shad were stocked suggesting that a mechanism other than shad was responsible for the changes in relative abundance. Additionally, larval abundances of yellow perch were highest during years when gizzard shad were present in East Krause Lake. Larval yellow perch abundances were highest in 2010 followed by 2008, 2007 and then 2009 in the two larger study lakes, Middle Lynn and Lardy, potentially suggesting that environmental factors were more influential to perch production than the presence of gizzard shad. Overall, gizzard shad likely had a positive effect on walleye abundance, growth and condition while apparently having little impact on yellow perch during this study. Thus, gizzard shad likely could be used as an additional prey resource, especially if juvenile densities could be increased, or if they were used in a system where walleye growth was slower or prey resources were more limiting. However, these results should be interpreted with caution. During this study gizzard shad densities (both adults and juveniles) were lower than in other South Dakota systems at least in part due to a lack of overwinter survival. If adult gizzard shad densities were higher it is possible that the outcomes of this project may have been different. Walleye growth and condition and possibly abundance
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would likely have increased more if gizzard shad densities increased; however, this would also increase the potential for negative effects on yellow perch, especially juveniles.
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TABLE OF CONTENTS
Influence of Gizzard Shad on Fish Community Ecology in Northeastern South Dakota Glacial Lakes ........................................................................................................ i ACKNOWLEDGEMENTS ............................................................................................ iii ABSTRACT ...................................................................................................................... vi TABLE OF CONTENTS .............................................................................................. xiv LIST OF TABLES ....................................................................................................... xviii LIST OF FIGURES .........................................................................................................xx CHAPTER 1. INTRODUCTION .....................................................................................1 CHAPTER 2. SURVIVAL, REPRODUCTION AND RECRUITMENT OF GIZZARD SHAD IN NORTHEASTERN SOUTH DAKOTA GLACIAL LAKES ................................................................................................................................8 Introduction ....................................................................................................................8 Methods .........................................................................................................................10 Study area ...................................................................................................................10 Gizzard shad collection and stocking .........................................................................11 Assessment of reproduction and recruitment .............................................................12 Overwinter survival ....................................................................................................13 Among water body comparisons ................................................................................14
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Results ...........................................................................................................................15 Gizzard shad collection and stocking .........................................................................15 Reproduction and recruitment....................................................................................15 Overwinter survival ....................................................................................................16 Among water body comparisons ................................................................................17 Discussion ......................................................................................................................17 CHAPTER 3. IMPACTS OF ADULT GIZZARD SHAD STOCKINGS ON POPULATION DYNAMIC RATES, DIETS AND ENERGY SOURCES OF WALLEYE AND YELLOW PERCH IN NORTHEASTERN SOUTH DAKOTA GLACIAL LAKES ........................................................................................29 Introduction ..................................................................................................................29 Methods .........................................................................................................................33 Study area ...................................................................................................................33 Adult gizzard shad stocking ........................................................................................34 Walleye stocking .........................................................................................................34 Yellow perch stocking .................................................................................................34 Fish collection ............................................................................................................35 Sample processing ......................................................................................................37 Laboratory analysis ....................................................................................................38 Data analysis ..............................................................................................................39 Results ...........................................................................................................................47
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Impacts of gizzard shad on walleye ............................................................................47 Fish collection........................................................................................................47 Walleye growth ......................................................................................................48 Annual mortality estimates ....................................................................................49 Relative abundance estimates ................................................................................49 Condition................................................................................................................50 Size structure..........................................................................................................51 Seasonal diets.........................................................................................................52 Stable isotope analysis ...........................................................................................56 Impacts of gizzard shad on yellow perch ...................................................................60 Fish collection........................................................................................................60 Yellow perch growth ..............................................................................................60 Annual mortality estimates ....................................................................................61 Relative abundance estimates ................................................................................61 Condition................................................................................................................62 Size structure..........................................................................................................63 Seasonal diets.........................................................................................................64 Stable isotope analysis ...........................................................................................68 Discussion ......................................................................................................................73
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CHAPTER 4. SUMMARY AND RESEARCH NEEDS ...........................................137 References ......................................................................................................................145
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LIST OF TABLES Table 2-1. Characteristics for all South Dakota water bodies from which gizzard shad (GZD) reproduction was compared. Ecoregions are characterized by the Level III Ecoregion as classified by the U.S. Environmental Protection Agency. Trophic state is based on the trophic state index (Carlson 1977). NR = naturally recruiting, SS = supplementally stocked, RE = natural range expansion, and ST = stocked. ............................................................................ 22 Table 2-2. Mean peak larval density (number/100 m3) estimates for gizzard shad from various South Dakota water bodies during 2008 and 2009. .............................. 23 Table 3-1. Total number of walleye collected from three northeastern South Dakota glacial lakes during each sampling period from 2007 through 2010. (Sept = September) ...................................................................................................... 82 Table 3-2. Comparison of models for predicting fish total length from otolith radius. Model evaluation r2 values were derived from comparing observed total length with predicted total length estimated from the otolith radius using each model. SSE is the sum of squares error derived from the residuals of observed total length at time of capture to predicted total length from each model based on otolith radius ............................................................................ 83 Table 3-3. Instantaneous (Z) and total annual (A) mortality rates for walleye from three northeastern South Dakota glacial lakes from 2007 through 2010. .......... 84 Table 3-4. Taxonomic groups present in walleye diets in Middle Lynn Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ................................... 85 Table 3-5. Taxonomic groups present in walleye diets in East Krause Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ................................... 86 Table 3-6. Taxonomic groups present in walleye diets in Lardy Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ...................................................... 87
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Table 3-7. Number of yellow perch collected from three northeastern South Dakota glacial lakes during each sampling period of each year. ................................... 88 Table 3-8. Instantaneous (Z) and total annual (A) mortality rates for yellow perch from three northeastern South Dakota glacial lakes from 2007 through 2010. . 89 Table 3-9. Taxonomic groups present in yellow perch diets in Middle Lynn Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ................................... 90 Table 3-10. Taxonomic groups present in yellow perch diets in East Krause Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ................................... 91 Table 3-11. Taxonomic groups present in yellow perch diets in Lardy Lake, South Dakota during spring (Sp; May), summer (Su; July) and autumn (Au; September) of 2007 through 2010. NS = none sampled. ................................... 92
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LIST OF FIGURES Figure 2-1. Inset is the state of South Dakota, United States. White dots represent water bodies sampled during the study. Shading represents mean annual temperature (°C) from 1971 to 2000 (U.S. Department of Agriculture 2010). ................................................................................................................ 24 Figure 2-2. Larval gizzard shad density estimates (number/100 m3±SE) for East Krause (black) and Middle Lynn (grey) lakes, South Dakota during the summer of 2008 (A) and 2009 (B) ................................................................... 25 Figure 2-3. Length-frequency histograms (10-mm length groups) for autumn age-0 gizzard shad for East Krause (A) and Middle Lynn (B) lakes, South Dakota in 2008 and Middle Lynn Lake (C), South Dakota in 2009. ............................ 26 Figure 2-4. Mean daily water temperature taken at the sediment-water interface at a depth of approximately 4 m of water in East Krause (black) and Middle Lynn (dark grey) lakes, South Dakota during the 2009-2010 winter. The grey, dashed horizontal line represents the threshold at which substantial mortality has been reported for gizzard shad. .................................................. 27 Figure 2-5. Mean weekly air temperatures from the National Weather Service (Weather Underground) during the 2007 to 2008 winter period (November through April) near Lake Byron (black line) and the 2008 to 2009 (grey line) and 2009 to 2010 (dashed grey line) winter periods near the northeastern South Dakota glacial lakes (Middle Lynn and East Krause). ...... 28 Figure 3-1. State of South Dakota with county names. Study lakes were located in north central Day County, South Dakota denoted by gray star ........................ 93 Figure 3-2. Annual growth increment of walleye from East Krause (A), Middle Lynn (B) and Lardy (C) lakes in northeastern South Dakota before (pre-shad period), during (shad period) and after (post-shad period) annual introductions of adult gizzard shad. Lines are the linear regressions for the pre-shad period (black), shad (black dashed) and post-shad (gray) periods. ... 94
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Figure 3-3. Mean catch per unit effort for all walleye collected from East Krause (black circles), Middle Lynn (white circles) and Lardy (grey circles) lakes, Day County, South Dakota during spring (May) standardized graded-mesh gill net surveys during 2007 through 2010. Error bars represent 80% confidence intervals .............................................................................................................. 95 Figure 3-4. Mean catch per hour of age-0 walleye (WAE) from East Krause (black circles), Middle Lynn (white circles), and Lardy (gray circles) lakes, Day County, South Dakota during autumn (September) nighttime electrofishing surveys in 2007 through 2010. Error bars represent 80% confidence intervals .............................................................................................................. 96 Figure 3-5. Relative weight (Wr) for walleye from East Krause Lake collected during May (A), July (B) and September (C) of 2007 through 2010. Asterisks next to the year in the legend denote significant differences in Wr with total length obtained using an analysis of variance. Horizontal lines represent above average (95 to 105) condition based on the standard weight equation. ............................................................................................... 97 Figure 3-6. Relative weight (Wr) for walleye from Middle Lynn Lake collected during May (A), July (B) and September (C) of 2007 through 2010. Asterisks next to the year in the legend denote significant differences in Wr with total length obtained using an analysis of variance. Horizontal lines represent above average (95 to 105) condition based on the standard weight equation ................................................................................................ 98 Figure 3-7. Relative weight (Wr) for walleye from Lardy Lake collected during May (A), July (B) and September (C) of 2007 through 2010. Asterisks next to the year in the legend denote significant differences in Wr with total length obtained using an analysis of variance. Horizontal lines represent above average (95 to 105) condition based on the standard weight equation ............ 99 Figure 3-8. Proportional size distribution (PSD) and proportion size distribution of preferred length (PSD-P) walleye from East Krause (black circles), Middle Lynn (white circles), and Lardy (gray circles) lakes, Day County, South Dakota estimated from spring gill net surveys in 2007 through 2010. Error bars represent 80% confidence intervals............................................... 100
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Figure 3-9. Percent of diets by number for walleye from Middle Lynn (Top), East Krause (Middle) and Lardy (Bottom) lakes, South Dakota during May, July and September of 2007 to 2010. Rare items include any taxa composing
